The Earth seen from Apollo 17.jpg
Hawk eating prey.jpgEuropean honey bee extracts nectar.jpg
Bufo boreas.jpgBlue Linckia Starfish.JPG
The scientific discipline of ecology addresses the full scale of life, from tiny bacteria to processes that span the entire planet. Ecologists study many diverse and complex relations among species, such as predation and pollination. The diversity of life is organized into different habitats, from terrestrial (middle) to aquatic ecosystems.

Ecology (from Greek: οἶκος, "house"; -λογία, "study of") is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount (biomass), number, and changing states of organisms within and among ecosystems. Ecosystems are hierarchical systems that are organized into a graded series of regularly interacting and semi-independent parts (e.g., species) that aggregate into higher orders of complex integrated wholes (e.g., communities). Ecosystems are sustained by the biodiversity within them. Biodiversity is the full-scale of life and its processes, including genes, species and ecosystems forming lineages that integrate into a complex and regenerative spatial arrangement of types, forms, and interactions. Ecosystems create biophysical feedback mechanisms between living (biotic) and nonliving (abiotic) components of the planet. These feedback loops regulate and sustain local communities, continental climate systems, and global biogeochemical cycles.

Ecology is a sub-discipline of biology, the study of life. The word "ecology" ("Ökologie") was coined in 1866 by the German scientist Ernst Haeckel (1834–1919). Ancient philosophers of Greece, including Hippocrates and Aristotle, were among the earliest to record notes and observations on the natural history of plants and animals. Modern ecology branched out of natural history and matured into a more rigorous science in the late 19th century. Charles Darwin's evolutionary treatise including the concept of adaptation, as it was introduced in 1859, is a pivotal cornerstone in modern ecological theory. Ecology is not synonymous with environment, environmentalism, natural history or environmental science. It is closely related to physiology, evolutionary biology, genetics and ethology. An understanding of how biodiversity affects ecological function is an important focus area in ecological studies. Ecologists seek to explain:

  • Life processes and adaptations
  • Distribution and abundance of organisms
  • The movement of materials and energy through living communities
  • The successional development of ecosystems, and
  • The abundance and distribution of biodiversity in context of the environment.

Ecology is a human science as well. There are many practical applications of ecology in conservation biology, wetland management, natural resource management (agriculture, forestry, fisheries), city planning (urban ecology), community health, economics, basic and applied science and human social interaction (human ecology). Ecosystems sustain every life-supporting function on the planet, including climate regulation, water filtration, soil formation (pedogenesis), food, fibers, medicines, erosion control, and many other natural features of scientific, historical or spiritual value.[1][2][3]


Integrative levels, scope, and scale of organization

Ecosystems regenerate after a disturbance such as fire, forming mosaics of different age groups structured across a landscape. Pictured are different seral stages in forested ecosystems starting from pioneers colonizing a disturbed site and maturing in successional stages leading to old-growth forests.

The scope of ecology covers a wide array of interacting levels of organization spanning micro-level (e.g., cells) to planetary scale (e.g., ecosphere) phenomena. Ecosystems, for example, contain populations of individuals that aggregate into distinct ecological communities. It can take thousands of years for ecological processes to mature through and until the final successional stages of a forest. The area of an ecosystem can vary greatly from tiny to vast. A single tree is of little consequence to the classification of a forest ecosystem, but critically relevant to the smaller organisms living in and on it.[4] Several generations of an aphid population can exist over the lifespan of a single leaf. Each of those aphids, in turn, support diverse bacterial communities.[5] The nature of connections in ecological communities cannot be explained by knowing the details of each species in isolation, because the emergent pattern is neither revealed nor predicted until the ecosystem is studied as an integrated whole. Some ecological principles, however, do exhibit collective properties where the sum of the components explain the properties of the whole, such as birth rates of a population being equal to the sum of individual births over a designated time frame.[6]

Hierarchical ecology

System behaviours must first be arrayed into levels of organization. Behaviors corresponding to higher levels occur at slow rates. Conversely, lower organizational levels exhibit rapid rates. For example, individual tree leaves respond rapidly to momentary changes in light intensity, CO2 concentration, and the like. The growth of the tree responds more slowly and integrates these short-term changes.[7]:76

The scale of ecological dynamics can operate like a closed island with respect to local site variables, such as aphids migrating on a tree, while at the same time remain open with regard to broader scale influences, such as atmosphere or climate. Hence, ecologists have devised means of hierarchically classifying ecosystems by analyzing data collected from finer scale units, such as vegetation associations, climate, and soil types, and integrate this information to identify larger emergent patterns of uniform organization and processes that operate on local to regional, landscape, and chronological scales.

To structure the study of ecology into a manageable framework of understanding, the biological world is conceptually organized as a nested hierarchy of organization, ranging in scale from genes, to cells, to tissues, to organs, to organisms, to species and up to the level of the biosphere.[8] Together these hierarchical scales of life form a panarchy[9][10] and they exhibit non-linear behaviours; "nonlinearity refers to the fact that effect and cause are disproportionate, so that small changes in critical variables, such as the numbers of nitrogen fixers, can lead to disproportionate, perhaps irreversible, changes in the system properties."[11]:14


Biodiversity is the variety of life and its processes. It includes the variety of living organisms, the genetic differences among them, the communities and ecosystems in which they occur, and the ecological and evolutionary processes that keep them functioning, yet ever changing and adapting.[12]:5

Biodiversity (an abbreviation of biological diversity) describes the diversity of life from genes to ecosystems and spans every level of biological organization. Biodiversity means different things to different people and there are many ways to index, measure, characterize, and represent its complex organization.[13][14] Biodiversity includes species diversity, ecosystem diversity, genetic diversity and the complex processes operating at and among these respective levels.[14][15][16] Biodiversity plays an important role in ecological health as much as it does for human health.[17][18] Preventing or prioritizing species extinctions is one way to preserve biodiversity, but populations, the genetic diversity within them and ecological processes, such as migration, are being threatened on global scales and disappearing rapidly as well. Conservation priorities and management techniques require different approaches and considerations to address the full ecological scope of biodiversity. Populations and species migration, for example, are more sensitive indicators of ecosystem services that sustain and contribute natural capital toward the well-being of humanity.[19][20][21][22] An understanding of biodiversity has practical application for ecosystem-based conservation planners as they make ecologically responsible decisions in management recommendations to consultant firms, governments and industry.[23]


The habitat of a species describes the environment over which a species is known to occur and the type of community that is formed as a result.[24] More specifically, "habitats can be defined as regions in environmental space that are composed of multiple dimensions, each representing a biotic or abiotic environmental variable; that is, any component or characteristic of the environment related directly (e.g. forage biomass and quality) or indirectly (e.g. elevation) to the use of a location by the animal."[25]:745 For example, the habitat might refer to an aquatic or terrestrial environment that can be further categorized as montane or alpine ecosystems. Habitat shifts provide important evidence of competition in nature where one population changes relative to the habitats that most other individuals of the species occupy. One population of a species of tropical lizards (Tropidurus hispidus), for example, has a flattened body relative to the main populations that live in open savanna. The population that lives in an isolated rock outcrop hides in crevasses where its flattened body may improve its performance. Habitat shifts also occur in the developmental life history of amphibians and many insects that transition from aquatic to terrestrial habitats. Biotope and habitat are sometimes used interchangeably, but the former applies to a communities environment, whereas the latter applies to a species' environment.[24][26][27]

Biodiversity of a coral reef. Corals adapt and modify their environment by forming calcium carbonate skeletons that provide growing conditions for future generations and form habitat for many other species.[28]


Termite mounds with varied heights of chimneys regulate gas exchange, temperature and other environmental parameters that are needed to sustain the internal physiology of the entire colony.[29][30]

There are many definitions of the niche dating back to 1917,[31] but G. Evelyn Hutchinson made conceptual advances in 1957[32][33] and introduced the most widely accepted definition: "which a species is able to persist and maintain stable population sizes."[31]:519 The ecological niche is a central concept in the ecology of organisms and is sub-divided into the fundamental and the realized niche. The fundamental niche is the set of environmental conditions under which a species is able to persist. The realized niche is the set of environmental plus ecological conditions under which a species persists.[31][33][34] The Hutchisonian niche is defined more technically as an "Euclidean hyperspace whose dimensions are defined as environmental variables and whose size is a function of the number of values that the environmental values may assume for which an organism has positive fitness."[35]:71

Biogeographical patterns and range distributions are explained or predicted through knowledge and understanding of a species traits and niche requirements.[36] Species have functional traits that are uniquely adapted to the ecological niche. A trait is a measurable property, phenotype, or characteristic of an organism that influences its performance. Genes play an important role in the development and expression of traits.[37] Resident species evolve traits that are fitted to their local environment. This tends to afford them a competitive advantage and discourages similarly adapted species from having an overlapping geographic range. The competitive exclusion principle suggests that two species cannot coexist indefinitely by living off the same limiting resource. When similarly adapted species are found to overlap geographically, closer inspection reveals subtle ecological differences in their habitat or dietary requirements.[38] Some models and empirical studies, however, suggest that disturbances can stabilize the coevolution and shared niche occupancy of similar species inhabiting species rich communities.[39] The habitat plus the niche is called the ecotope, which is defined as the full range of environmental and biological variables affecting an entire species.[24]

Niche construction

Organisms are subject to environmental pressures, but they are also modifiers of their habitats. The regulatory feedback between organisms and their environment can modify conditions from local (e.g., a beaver pond) to global scales (e.g., Gaia), over time and even after death, such as decaying logs or silica skeleton deposits from marine organisms.[40] The process and concept of ecosystem engineering has also been called niche construction. Ecosystem engineers are defined as: "...organisms that directly or indirectly modulate the availability of resources to other species, by causing physical state changes in biotic or abiotic materials. In so doing they modify, maintain and create habitats."[41]:373

The ecosystem engineering concept has stimulated a new appreciation for the degree of influence that organisms have on the ecosystem and evolutionary process. The terms niche construction are more often used in reference to the under appreciated feedback mechanism of natural selection imparting forces on the abiotic niche.[29][42] An example of natural selection through ecosystem engineering occurs in the nests of social insects, including ants, bees, wasps, and termites. There is an emergent homeostasis or homeorhesis in the structure of the nest that regulates, maintains and defends the physiology of the entire colony. Termite mounds, for example, maintain a constant internal temperature through the design of air-conditioning chimneys. The structure of the nests themselves are subject to the forces of natural selection. Moreover, the nest can survive over successive generations, which means that ancestors inherit both genetic material and a legacy niche that was constructed before their time.[6][29][30][43]


Biomes are larger units of organization that categorize regions of the Earth's ecosystems mainly according to the structure and composition of vegetation.[44] Different researchers have applied different methods to define continental boundaries of biomes dominated by different functional types of vegetative communities that are limited in distribution by climate, precipitation, weather and other environmental variables. Examples of biome names include: tropical rainforest, temperate broadleaf and mixed forests, temperate deciduous forest, taiga, tundra, hot desert, and polar desert.[45] Other researchers have recently started to categorize other types of biomes, such as the human and oceanic microbiomes. To a microbe, the human body is a habitat and a landscape.[46] The microbiome has been largely discovered through advances in molecular genetics that have revealed a hidden richness of microbial diversity on the planet. The oceanic microbiome plays a significant role in the ecological biogeochemistry of the planet's oceans.[47]


Ecological theory has been used to explain self-emergent regulatory phenomena at the planetary scale. The largest scale of ecological organization is the biosphere: the total sum of ecosystems on the planet. Ecological relationships regulate the flux of energy, nutrients, and climate all the way up to the planetary scale. For example, the dynamic history of the planetary CO2 and O2 composition of the atmosphere has been largely determined by the biogenic flux of gases coming from respiration and photosynthesis, with levels fluctuating over time and in relation to the ecology and evolution of plants and animals.[48] When sub-component parts are organized into a whole there are oftentimes emergent properties that describe the nature of the system. The Gaia hypothesis is an example of holism applied in ecological theory.[49] The ecology of the planet acts as a single regulatory or holistic unit called Gaia. The Gaia hypothesis states that there is an emergent feedback loop generated by the metabolism of living organisms that maintains the temperature of the Earth and atmospheric conditions within a narrow self-regulating range of tolerance.[50]

Population ecology

The population is the unit of analysis in population ecology. A population consists of individuals of the same species that live, interact and migrate through the same niche and habitat.[51] A primary law of population ecology is the Malthusian growth model.[52] This law states that:

"...a population will grow (or decline) exponentially as long as the environment experienced by all individuals in the population remains constant."[52]:18

This Malthusian premise provides the basis for formulating predictive theories and tests that follow. Simplified population models usually start with four variables including death, birth, immigration, and emigration. Mathematical models are used to calculate changes in population demographics using a null model. A null model is used as a null hypothesis for statistical testing. The null hypothesis states that random processes create observed patterns. Alternatively the patterns differ significantly from the random model and require further explanation. Models can be mathematically complex where "...several competing hypotheses are simultaneously confronted with the data."[53] An example of an introductory population model describes a closed population, such as on an island, where immigration and emigration does not take place. In these island models the rate of population change is described by:

\frac{dN}{dT} = B - D = bN - dN = (b - d)N = rN,

where N is the total number of individuals in the population, B is the number of births, D is the number of deaths, b and d are the per capita rates of birth and death respectively, and r is the per capita rate of population change. This formula can be read out as the rate of change in the population (dN/dT) is equal to births minus deaths (B – D).[52][54]

Using these modelling techniques, Malthus' population principle of growth was later transformed into a model known as the logistic equation:

\frac{dN}{dT} = aN\left(1-\frac{N}{K}\right),

where N is the number of individuals measured as biomass density, a is the maximum per-capita rate of change, and K is the carrying capacity of the population. The formula can be read as follows: the rate of change in the population (dN/dT) is equal to growth (aN) that is limited by carrying capacity (1 – N/K). The discipline of population ecology builds upon these introductory models to further understand demographic processes in real study populations and conduct statistical tests. The field of population ecology often uses data on life history and matrix algebra to develop projection matrices on fecundity and survivorship. This information is used for managing wildlife stocks and setting harvest quotas.[54][55]

Metapopulations and migration

Populations are also studied and modeled according to the metapopulation concept. The metapopulation concept was introduced in 1969:[56] "as a population of populations which go extinct locally and recolonize."[57]:105 Metapopulation ecology is another statistical approach that is often used in conservation research.[58] Metapopulation research simplifies the landscape into patches of varying levels of quality.[59] Metapopulations are linked by the migratory behaviours of organisms. Animal migration is set apart from other kinds of movement because it involves the seasonal departure and return of individuals from one habitat to another.[60] Migration is also a population level phenomenon, such as the migration routes followed by plants as they occupied northern post-glacial environments. Plant ecologists rely on pollen records that accumulate and stratify in wetlands to reconstruct the timing of plant migration and dispersal relative to historic and contemporary climates. These migration routes involved an expansion of the range as plant populations expanded from one area to another. There is a larger taxonomy of movement, such as commuting, foraging, territorial behaviour, stasis, and ranging. Dispersal is usually distinguished from migration because it involves the one way permanent movement of individuals from their birth population into another population.[61][62]

In metapopulation terminology there are emigrants (individuals that leave a patch), immigrants (individuals that move into a patch) and sites are classed either as sources or sinks. A site is a generic term that refers to places where ecologists sample populations, such as ponds or defined sampling areas in a forest. Source patches are productive sites that generate a seasonal supply of juveniles that migrate to other patch locations. Sink patches are unproductive sites that only receive migrants and will go extinct unless rescued by an adjacent source patch or environmental conditions become more favorable. Metapopulation models examine patch dynamics over time to answer questions about spatial and demographic ecology. The ecology of metapopulations is a dynamic process of extinction and colonization. Small patches of lower quality (i.e., sinks) are maintained or rescued by a seasonal influx of new immigrants. A dynamic metapopulation structure evolves from year to year, where some patches are sinks in dry years and become sources when conditions are more favorable. Ecologists use a mixture of computer models and field studies to explain metapopulation structure.[63][64]

Community ecology

Interspecific interactions such as predation are a key aspect of community ecology.

Community ecology examines how interactions among species and their environment affect the abundance, distribution and diversity of species within communities.

Johnson & Stinchcomb[65]:250

Community ecology is the study of the interactions among a collection of interdependent species that cohabitate the same geographic area. An example of a study in community ecology might measure primary production in a wetland in relation to decomposition and consumption rates. This requires an understanding of the community connections between plants (i.e., primary producers) and the decomposers (e.g., fungi and bacteria).[66] or the analysis of predator-prey dynamics affecting amphibian biomass.[67] Food webs and trophic levels are two widely employed conceptual models used to explain the linkages among species.[68][69]

Ecosystem ecology

These ecosystems, as we may call them, are of the most various kinds and sizes. They form one category of the multitudinous physical systems of the universe, which range from the universe as a whole down to the atom.

Figure 1. A riparian forest in the White Mountains, New Hampshire (USA), an example of ecosystem ecology

The concept of the ecosystem was fully synthesized in 1935 to describe habitats within biomes that form an integrated whole and a dynamically responsive system having both physical and biological complexes. However, the underlying concept can be traced back to 1864 in the published work of George Perkins Marsh ("Man and Nature").[71][72] Within an ecosystem there are inseparable ties that link organisms to the physical and biological components of their environment to which they are adapted.[70] Ecosystems are complex adaptive systems where the interaction of life processes form self-organizing patterns across different scales of time and space.[73] terrestrial, freshwater, atmospheric, and marine ecosystems very broadly cover the major types. Differences stem from the nature of the unique physical environments that shapes the biodiversity within each. A more recent addition to ecosystem ecology are the novel technoecosystems of the anthropocene.[6]

Food webs

A food web is the archetypal ecological network. Plants capture and convert solar energy into the biomolecular bonds of simple sugars during photosynthesis. This food energy is transferred through a series of organisms starting with those that feed on plants and are themselves consumed. The simplified linear feeding pathways that move from a basal trophic species to a top consumer is called the food chain. The larger interlocking pattern of food chains in an ecological community creates a complex food web. Food webs are a type of concept map or a heuristic device that is used illustrate and study pathways of energy and material flows.[7][74][75]

Generalized food web of waterbirds from Chesapeake Bay

Food webs are often limited relative to the real world. Complete empirical measurements are generally restricted to a specific habitat, such as a cave or a pond. Principles gleaned from food web microcosm studies are used to extrapolate smaller dynamic concepts to larger systems.[76] Feeding relations require extensive investigations into the gut contents of organisms, which can be very difficult to decipher, or (more recently) stable isotopes can be used to trace the flow of nutrient diets and energy through a food web.[77] While food webs often give an incomplete measure of ecosystems, they are nonetheless a valuable tool in understanding community ecosystems.[78]

Food-webs exhibit principals of ecological emergence through the nature of trophic entanglement, where some species have many weak feeding links (e.g., omnivores) while some are more specialized with fewer stronger feeding links (e.g., primary predators). Theoretical and empirical studies identify non-random emergent patterns of few strong and many weak linkages that serve to explain how ecological communities remain stable over time.[79] Food-webs have compartments, where the many strong interactions create subgroups among some members in a community and the few weak interactions occur between these subgroups. These compartments increase the stability of food-webs.[80] As plants grow, they accumulate carbohydrates and are eaten by grazing herbivores. Step by step lines or relations are drawn until a web of life is illustrated.[75][81][82][83]

Trophic levels

A trophic pyramid (a) and a food-web (b) illustrating ecological relationships among creatures that are typical of a northern Boreal terrestrial ecosystem. The trophic pyramid roughly represents the biomass (usually measured as total dry-weight) at each level. Plants generally have the greatest biomass. Names of trophic categories are shown to the right of the pyramid. Some ecosystems, such as many wetlands, do not organize as a strict pyramid, because aquatic plants are not as productive as long-lived terrestrial plants such as trees. Ecological trophic pyramids are typically one of three kinds: 1) pyramid of numbers, 2) pyramid of biomass, or 3) pyramid of energy.[6]

The Greek root of the word troph, τροφή, trophē, means food or feeding. Links in food-webs primarily connect feeding relations or trophism among species. Biodiversity within ecosystems can be organized into vertical and horizontal dimensions. The vertical dimension represents feeding relations that become further removed from the base of the food chain up toward top predators. A trophic level is defined as "a group of organisms acquiring a considerable majority of its energy from the adjacent level nearer the abiotic source."[84]:383 The horizontal dimension represents the abundance or biomass at each level.[85] When the relative abundance or biomass of each functional feeding group is stacked into their respective trophic levels they naturally sort into a 'pyramid of numbers'.[86]

Functional groups are broadly categorized as autotrophs (or primary producers), heterotrophs (or consumers), and detrivores (or decomposers). Autotrophs are organisms that can produce their own food (production is greater than respiration) and are usually plants or cyanobacteria that are capable of photosynthesis but can also be other organisms such as bacteria near ocean vents that are capable of chemosynthesis. Heterotrophs are organisms that must feed on others for nourishment and energy (respiration exceeds production).[6] Heterotrophs can be further sub-divided into different functional groups, including: primary consumers (strict herbivores), secondary consumers (carnivorous predators that feed exclusively on herbivores) and tertiary consumers (predators that feed on a mix of herbivores and predators).[87] Omnivores do not fit neatly into a functional category because they eat both plant and animal tissues. It has been suggested that omnivores have a greater functional influence as predators because relative to herbivores they are comparatively inefficient at grazing.[88]

Trophic levels are part of the holistic or complex systems view of ecosystems.[89][90] Each trophic level contains unrelated species that grouped together because they share common ecological functions. Grouping functionally similar species into a trophic system gives a macroscopic image of the larger functional design.[91] While the notion of trophic levels provides insight into energy flow and top-down control within food webs, it is troubled by the prevalence of omnivory in real ecosystems. This has lead some ecologists to "reiterate that the notion that species clearly aggregate into discrete, homogeneous trophic levels is fiction."[92]:815 Nonetheless, recent studies have shown that real trophic levels do exist, but "above the herbivore trophic level, food webs are better characterized as a tangled web of omnivores."[93]:612

Keystone species

A keystone species is a species that is disproportionately connected to more species in the food-web. Keystone species have lower levels of biomass in the trophic pyramid relative to the importance of their role. The many connections that a keystone species holds means that it maintains the organization and structure of entire communities. The loss of a keystone species results in a range of dramatic cascading effects that alters trophic dynamics, other food-web connections and can cause the extinction of other species in the community.[94][95]

Sea otters (Enhydra lutris) are commonly cited as an example of a keystone species because they limit the density of sea urchins that feed on kelp. If sea otters are removed from the system, the urchins graze until the kelp beds disappear and this has a dramatic effect on community structure.[96] Hunting of sea otters, for example, is thought to have indirectly led to the extinction of the Steller's Sea Cow (Hydrodamalis gigas).[97] While the keystone species concept has been used extensively as a conservation tool, it has been criticized for being poorly defined from an operational stance. It is very difficult to experimentally determine in each different ecosystem what species may hold a keystone role. Furthermore, food-web theory suggests that keystone species may not be all that common. It is therefore unclear how generally the keystone species model can be applied.[96][98]


Soil is the living top layer of mineral and organic dirt that covers the surface of the planet, it is the chief organizing centre of most ecosystem functions, and it is of critical importance in agricultural science and ecology. The decomposition of dead organic matter, such as leaves falling on the forest floor, turns into soils containing minerals and nutrients that feed into plant production. The total sum of the planet's soil ecosystems is called the pedosphere where a very large proportion of the Earth's biodiversity sorts into other trophic levels. Invertebrates that feed and shred larger leaves, for example, create smaller bits for smaller organisms in the feeding chain. Collectively, these are the detrivores that regulate soil formation. [99][100][101][102] Tree roots, fungi, bacteria, worms, ants, beetles, centipedes, spiders, mammals, birds, reptiles, amphibians and other less familiar creatures all work to create the trophic web of life in soil ecosystems. As organisms feed and migrate through soils they physically displace materials, which is an important ecological process called bioturbation. Bioturbation helps to aerate the soils, thus stimulating hetertrophic growth and production. Biomass of soil microorganisms are influenced by and feed back into the trophic dynamics of the exposed solar surface ecology. Paleoecological studies of soils places the origin for bioturbation to a time before the Cambrian period. Other events, such as the evolution of trees and amphibians moving into land in the Devonian period played a significant role in the development of the ecological trophism in soils.[67][102][103]

Ecological complexity

Complexity is easily understood as a large computational effort needed to piece together numerous interacting parts exceeding the iterative memory capacity of the human mind. Global patterns of biological diversity are complex. This biocomplexity stems from the interplay among ecological processes that operate and influence patterns at different scales that grade into each other, such as transitional areas or ecotones spanning landscapes.[104] Complexity stems from the interplay among levels of biological organization as energy and matter is integrated into larger units that superimpose onto the smaller parts. "What were wholes on one level become parts on a higher one."[105]:209 Small scale patterns do not necessarily explain large scale phenomena, otherwise captured in the expression (coined by Aristotle) 'the sum is greater than the parts'.[106][107]

"Complexity in ecology is of at least six distinct types: spatial, temporal, structural, process, behavioral, and geometric."[108]:3 Out of these principles, ecologists have identified emergent and self-organizing phenomena that operate at different environmental scales of influence, ranging from molecular to planetary, and these require different sets of scientific explanation at each integrative level.[50][109] Ecological complexity relates to the dynamic resilience of ecosystems that transition to multiple shifting steady-states directed by random fluctuations of history.[9][110] Long-term ecological studies provide important track records to better understand the complexity and resilience of ecosystems over longer temporal and broader spatial scales. The International Long Term Ecological Network[111] manages and exchanges scientific information among research sites. The longest experiment in existence is the Park Grass Experiment that was initiated in 1856.[112] Another example includes the Hubbard Brook study in operation since 1960.[113]


The biological organization of life self-organizes into layers of emergent whole systems that function according to nonreducible properties called holism. This means that higher order patterns of a whole functional system, such as an ecosystem, cannot be predicted or understood by a simple summation of the parts. "New properties emerge because the components interact, not because the basic nature of the components is changed."[6]:8

Ecological studies are necessarily holistic as opposed to reductionistic.[109][114][editorializing] Holism has three scientific meanings or uses that identify with: 1) the mechanistic complexity of ecosystems, 2) the practical description of patterns in quantitative reductionist terms where correlations may be identified but nothing is understood about the causal relations without reference to the whole system, which leads to 3) a metaphysical hierarchy whereby the causal relations of larger systems are understood without reference to the smaller parts. An example of the metaphysical aspect to holism is identified in the trend of increased exterior thickness in shells of different species. The reason for a thickness increase can be understood through reference to principals of natural selection via predation without need to reference or understand the biomolecular properties of the exterior shells.[115]

Relation to evolution

Ecology and evolution are considered sister disciplines of the life sciences. Natural selection, life history, development, adaptation, populations, and inheritance are examples of concepts that thread equally into ecological and evolutionary theory. Morphological, behavioral and/or genetic traits, for example, can be mapped onto evolutionary trees to study the historical development of a species in relation to their functions and roles in different ecological circumstances. In this framework, the analytical tools of ecologists and evolutionists overlap as they organize, classify and investigate life through common systematic principals, such as phylogenetics or the Linnaean system of taxonomy.[116] The two disciplines often appear together, such as in the title of the journal Trends in Ecology and Evolution.[117] There is no sharp boundary separating ecology from evolution and they differ more in their areas of applied focus. Both disciplines discover and explain emergent and unique properties and processes operating across different spatial or temporal scales of organization.[50][118][119] While the boundary between ecology and evolution is not always clear, it is understood that ecologists study the abiotic and biotic factors that influence the evolutionary process.[120][121]

Behavioral ecology

Social display and color variation in differently adapted species of chameleons (Bradypodion spp.). Chameleons change their skin color to match their background as a behavioral defense mechanism and also use color to communicate with other members of their species, such as dominant (left) versus submissive (right) patterns shown in the three species (A-C) above.[122]

All organisms are motile to some extent. Even plants express complex behavior, including memory and communication.[123] Behavioral ecology is the study of ethology and its ecological and evolutionary implications. Ethology is the study of observable movement or behavior in nature. This could include investigations of motile sperm of plants, mobile phytoplankton, zooplankton swimming toward the female egg, the cultivation of fungi by weevils, the mating dance of a salamander, or social gatherings of amoeba.[124][125][126][127][128]

Adaptation is the central unifying concept in behavioral ecology.[129] Behaviors can be recorded as traits and inherited in much the same way that eye and hair color can. Behaviors evolve and become adapted to the ecosystem because they are subject to the forces of natural selection.[15] Hence, behaviors can be adaptive, meaning that they evolve functional utilities that increases reproductive success for the individuals that inherit such traits.[130] This is also the technical definition for fitness in biology, which is a measure of reproductive success over successive generations.[15]

Predator-prey interactions are an introductory concept into food-web studies as well as behavioral ecology.[131] Prey species can exhibit different kinds of behavioral adaptations to predators, such as avoid, flee or defend. Many prey species are faced with multiple predators that differ in the degree of danger posed. To be adapted to their environment and face predatory threats, organisms must balance their energy budgets as they invest in different aspects of their life history, such as growth, feeding, mating, socializing, or modifying their habitat. Hypotheses posited in behavioral ecology are generally based on adaptive principals of conservation, optimization or efficiency.[34][120][132] For example,

"The threat-sensitive predator avoidance hypothesis predicts that prey should assess the degree of threat posed by different predators and match their behavior according to current levels of risk."[133]

"The optimal flight initiation distance occurs where expected postencounter fitness is maximized, which depends on the prey's initial fitness, benefits obtainable by not fleeing, energetic escape costs, and expected fitness loss due to predation risk."[134]

Symbiosis: Leafhoppers (Eurymela fenestrata) are protected by ants (Iridomyrmex purpureus) in a symbiotic relationship. The ants protect the leafhoppers from predators and in return the leafhoppers feeding on plants exude honeydew from their anus that provides energy and nutrients to tending ants.[135]

Elaborate sexual displays and posturing are encountered in the behavioral ecology of animals. The birds of paradise, for example, display elaborate ornaments and song during courtship. These displays serve a dual purpose of signaling healthy or well-adapted individuals and desirable genes. The elaborate displays are driven by sexual selection as an advertisement of quality of traits among male suitors.[136]

Social ecology

Social ecological behaviors are notable in the social insects, slime moulds, social spiders, human society, and naked mole rats where eusocialism has evolved. Social behaviors include reciprocally beneficial behaviors among kin and nest mates.[15][126][137] Social behaviors evolve from kin and group selection. Kin selection explains altruism through genetic relationships, whereby an altruistic behavior leading to death is rewarded by the survival of genetic copies distributed among surviving relatives. The social insects, including ants, bees and wasps are most famously studied for this type of relationship because the male drones are clones that share the same genetic make-up as every other male in the colony.[15] In contrast, group selectionists find examples of altruism among non-genetic relatives and explain this through selection acting on the group, whereby it becomes selectively advantageous for groups if their members express altruistic behaviors to one another. Groups that are predominantly altruists beat groups that are predominantly selfish.[15][138]


Ecological interactions can be divided into host and associate relationships. A host is any entity that harbors another that is called the associate.[139] Host and associate relationships among species that are mutually or reciprocally beneficial are called mutualisms. If the host and associate are physically connected, the relationship is called symbiosis. Approximately 60% of all plants, for example, have a symbiotic relationship with arbuscular mycorrhizal fungi. Symbiotic plants and fungi exchange carbohydrates for mineral nutrients.[140] Symbiosis differs from indirect mutualisms where the organisms live apart. For example, tropical rainforests regulate the Earth's atmosphere. Trees living in the equatorial regions of the planet supply oxygen into the atmosphere that sustains species living in distant polar regions of the planet. This relationship is called commensalism because many other host species receive the benefits of clean air at no cost or harm to the associate tree species supplying the oxygen.[141] The host and associate relationship is called parasitism if one species benefits while the other suffers. Competition among species or among members of the same species is defined as reciprocal antagonism, such as grasses competing for growth space.[142]

Parasites: A harvestman arachnid is parasitized by mites. This is parasitism because the harvestman is being consumed as its juices are slowly sucked out while the mites gain all the benefits traveling on and feeding off of their host.

Popular ecological study systems for mutualism include, fungus-growing ants employing agricultural symbiosis, bacteria living in the guts of insects and other organisms, the fig wasp and yucca moth pollination complex, lichens with fungi and photosynthetic algae, and corals with photosynthetic algae.[143][144] Nevertheless, many organisms exploit host rewards without reciprocating and thus have been branded with a myriad of not-very-flattering names such as 'cheaters', 'exploiters', 'robbers', and 'thieves'. Although cheaters impose several host cots (e.g., via damage to their reproductive organs or propagules, denying the services of a beneficial partner), their net effect on host fitness is not necessarily negative and, thus, becomes difficult to forecast.[145][146]


The word biogeography is an amalgamation of biology and geography. Biogeography is the comparative study of the geographic distribution of organisms and the corresponding evolution of their traits in space and time.[147] The Journal of Biogeography was established in 1974.[148] Biogeography and ecology share many of their disciplinary roots. For example, the theory of island biogeography, published by the mathematician Robert MacArthur and ecologist Edward O. Wilson in 1967[149] is considered one of the fundamentals of ecological theory.[150]

Biogeography has a long history in the natural sciences where questions arise concerning the spatial distribution of plants and animals. Ecology and evolution provide the explanatory context for biogeographical studies.[147] Biogeographical patterns result from ecological processes that influence range distributions, such as migration and dispersal.[150] and from historical processes that split populations or species into different areas.[151] The biogeographic processes that result in the natural splitting of species explains much of the modern distribution of the Earth's biota. The splitting of lineages in a species is called vicariance biogeography and it is a sub-discipline of biogeography.[151][152][153] There are also practical applications in the field of biogeography concerning ecological systems and processes. For example, the range and distribution of biodiversity and invasive species responding to climate change is a serious concern and active area of research in context of global warming.[20][154]

r/K-Selection theory

A population ecology concept (introduced in MacArthur and Wilson's (1967) book, The Theory of Island Biogeography) is r/K selection theory, one of the first predictive models in ecology used to explain life-history evolution. The premise behind the r/K selection model is that natural selection pressures change according to population density. For example, when an island is first colonized, density of individuals is low. The initial increase in population size is not limited by competition, leaving an abundance of available resources for rapid population growth. These early phases of population growth experience density-independent forces of natural selection, which is called r-selection. As the population becomes more crowded, it approaches the island's carrying capacity, thus forcing individuals to compete more heavily for fewer available resources. Under crowded conditions the population experiences density-dependent forces of natural selection, called K-selection.[155]

In the r/K-selection model, the first variable r is the intrinsic rate of natural increase in population size and the second variable K is the carrying capacity of a population.[34] Different species evolve different life-history strategies spanning a continuum between these two selective forces. An r-selected species is one that has high birth rates, low levels of parental investment, and high rates of mortality before individuals reach maturity. Evolution favors high rates of fecundity in r-selected species. Many kinds of insects and invasive species exhibit r-selected characteristics. In contrast, a K-selected species has low rates of fecundity, high levels of parental investment in the young, and low rates of mortality as individuals mature. Humans and elephants are examples of species exhibiting K-selected characteristics, including longevity and efficiency in the conversion of more resources into fewer offspring.[149][156]

Molecular ecology

The important relationship between ecology and genetic inheritance predates modern techniques for molecular analysis. Molecular ecological research became more feasible with the development of rapid and accessible genetic technologies, such as the polymerase chain reaction (PCR). The rise of molecular technologies and influx of research questions into this new ecological field resulted in the publication Molecular Ecology in 1992.[157] Molecular ecology uses various analytical techniques to study genes in an evolutionary and ecological context. In 1994, John Avise also played a leading role in this area of science with the publication of his book, Molecular Markers, Natural History and Evolution.[158] Newer technologies opened a wave of genetic analysis into organisms once difficult to study from an ecological or evolutionary standpoint, such as bacteria, fungi and nematodes. Molecular ecology engendered a new research paradigm for investigating ecological questions considered otherwise intractable. Molecular investigations revealed previously obscured details in the tiny intricacies of nature and improved resolution into probing questions about behavioral and biogeographical ecology.[158] For example, molecular ecology revealed promiscuous sexual behavior and multiple male partners in tree swallows previously thought to be socially monogamous.[159] In a biogeographical context, the marriage between genetics, ecology and evolution resulted in a new sub-discipline called phylogeography.[160]

Human ecology

Human ecology is the interdisciplinary investigation into the ecology of our species. "Human ecology may be defined: (1) from a bio-ecological standpoint as the study of man as the ecological dominant in plant and animal communities and systems; (2) from a bio-ecological standpoint as simply another animal affecting and being affected by his physical environment; and (3) as a human being, somehow different from animal life in general, interacting with physical and modified environments in a distinctive and creative way. A truly interdisciplinary human ecology will most likely address itself to all three."[161] The term human ecology was formally introduced in 1921, but many sociologists, geographers, psychologists, and other disciplines were interested in human relations to natural systems centuries prior, especially in the late 19th century.[161][162] Some authors have identified a new unifying science in coupled human and natural systems that builds upon, but moves beyond the field human ecology.[163] Ecology is as much a biological science as it is a human science.[6] "Perhaps the most important implication involves our view of human society. Homo sapiens is not an external disturbance, it is a keystone species within the system. In the long term, it may not be the magnitude of extracted goods and services that will determine sustainability. It may well be our disruption of ecological recovery and stability mechanisms that determines system collapse."[72]:3282

Relation to the environment

The environment is dynamically interlinked, imposed upon and constrains organisms at any time throughout their life cycle.[164] Like the term ecology, environment has different conceptual meanings and to many these terms also overlap with the concept of nature. Environment "...includes the physical world, the social world of human relations and the built world of human creation."[165]:62 The environment in ecosystems includes both physical parameters and biotic attributes. The physical environment is external to the level of biological organization under investigation, including abiotic factors such as temperature, radiation, light, chemistry, climate and geology. The biotic environment includes genes, cells, organisms, members of the same species (conspecifics) and other species that share a habitat.[166] The laws of thermodynamics applies to ecology by means of its physical state. Armed with an understanding of metabolic and thermodynamic principles a complete accounting of energy and material flow can be traced through an ecosystem.[167]

Environmental and ecological relations are studied through reference to conceptually manageable and isolated parts. Once the effective environmental components are understood they conceptually link back together as a holocoenotic[168] system. In other words, the organism and the environment form a dynamic whole (or umwelt).[169]:252 Change in one ecological or environmental factor can concurrently affect the dynamic state of an entire ecosystem.[170][171]

Disturbance and resilience

Ecosystems are regularly confronted with natural environmental variations and disturbances over time and geographic space. A disturbance is any process that removes living biomass from a community, such as a fire, flood, drought, or predation.[172] Fluctuations causing disturbance occur over vastly different ranges in terms of magnitudes as well as distances and time periods.[173] Disturbances, such as fire, are both cause and product of natural fluctuations in death rates, species assemblages, and biomass densities within an ecological community. These disturbances create places of renewal where new directions emerge out of the patchwork of natural experimentation and opportunity.[172][174] [175] Ecological resilience is a cornerstone theory in ecosystem management. Biodiversity fuels the resilience of ecosystems acting as a kind of regenerative insurance.[175]

Metabolism and the early atmosphere

Metabolism – the rate at which energy and material resources are taken up from the environment, transformed within an organism, and allocated to maintenance, growth and reproduction – is a fundamental physiological trait.

Ernst et al.[176]:991

The Earth formed approximately 4.5 billion years ago[177] and environmental conditions were too extreme for life to form for the first 500 million years. During this early Hadean period, the Earth started to cool, allowing a crust and oceans to form. Environmental conditions were unsuitable for the origins of life for the first billion years after the Earth formed. The Earth's atmosphere transformed from being dominated by hydrogen, to one composed mostly of methane and ammonia. Over the next billion years the metabolic activity of life transformed the atmosphere to higher concentrations of carbon dioxide, nitrogen, and water vapor. These gases changed the way that light from the sun hit the Earth's surface and greenhouse effects trapped heat. There were untapped sources of free energy within the mixture of reducing and oxidizing gasses that set the stage for primitive ecosystems to evolve and, in turn, the atmosphere also evolved.[178]

The leaf is the primary site of photosynthesis in most plants.

Throughout history, the Earth's atmosphere and biogeochemical cycles have been in a dynamic equilibrium with planetary ecosystems. The history is characterized by periods of significant transformation followed by millions of years of stability.[179] The evolution of the earliest organisms, likely anaerobic methanogen microbes, started the process by converting atmospheric hydrogen into methane (4H2 + CO2 → CH4 + 2H2O). Anoxygenic photosynthesis converting hydrogen sulfide into other sulfur compounds or water (for example 2H2S + CO2 + hv → CH2O + H2O + 2S), as occurs in deep sea hydrothermal vents today, reduced hydrogen concentrations and increased atmospheric methane. Early forms of fermentation also increased levels of atmospheric methane. The transition to an oxygen dominant atmosphere (the Great Oxidation) did not begin until approximately 2.4-2.3 billion years ago, but photosynthetic processes started 0.3 to 1 billion years prior.[179][180]

Radiation: heat, temperature and light

The biology of life operates within a certain range of temperatures. Heat is a form of energy that regulates temperature. Heat affects growth rates, activity, behavior and primary production. Temperature is largely dependent on the incidence of solar radiation. The latitudinal and longitudinal spatial variation of temperature greatly affects climates and consequently the distribution of biodiversity and levels of primary production in different ecosystems or biomes across the planet. Heat and temperature relate importantly to metabolic activity. Poikilotherms, for example, have a body temperature that is largely regulated and dependent on the temperature of the external environment. In contrast, homeotherms regulate their internal body temperature by expending metabolic energy.[120][121][167]

There is a relationship between light, primary production, and ecological energy budgets. Sunlight is the primary input of energy into the planet's ecosystems. Light is composed of electromagnetic energy of different wavelengths. Radiant energy from the sun generates heat, provides photons of light measured as active energy in the chemical reactions of life, and also acts as a catalyst for genetic mutation.[120][121][167] Plants, algae, and some bacteria absorb light and assimilate the energy through photosynthesis. Organisms capable of assimilating energy by photosynthesis or through inorganic fixation of H2S are autotrophs. Autotrophs—responsible for primary production—assimilate light energy that becomes metabolically stored as potential energy in the form of biochemical enthalpic bonds.[120][121][167]

Physical environments


Wetland conditions such as shallow water, high plant productivity, and anaerobic substrates provide a suitable environment for important physical, biological, and chemical processes. Because of these processes, wetlands play a vital role in global nutrient and element cycles.:29[181]

The rate of diffusion of carbon dioxide and oxygen is approximately 10,000 times slower in water than it is in air. When soils become flooded, they quickly lose oxygen and transform into a low-concentration (hypoxic - O2 concentration lower than 2 mg/liter) environment and eventually become completely (anoxic) environment where anaerobic bacteria thrive among the roots. Water also influences the spectral composition and amount of light as it reflects off the water surface and submerged particles.[181] Aquatic plants exhibit a wide variety of morphological and physiological adaptations that allow them to survive, compete and diversify these environments. For example, the roots and stems develop large air spaces (Aerenchyma) that regulate the efficient transportation gases (for example, CO2 and O2) used in respiration and photosynthesis. In drained soil, microorganisms use oxygen during respiration. In aquatic environments, anaerobic soil microorganisms use nitrate, manganese ions, ferric ions, sulfate, carbon dioxide and some organic compounds. The activity of soil microorganisms and the chemistry of the water reduces the oxidation-reduction potentials of the water. Carbon dioxide, for example, is reduced to methane (CH4) by methanogenic bacteria. Salt water plants (or halophytes) have specialized physiological adaptations, such as the development of special organs for shedding salt and osmo-regulate their internal salt (NaCl) concentrations, to live in estuarine, brackish, or oceanic environments.[181] The physiology of fish is also specially adapted to deal with high levels of salt through osmoregulation. Their gills form electrochemical gradients that mediate salt excresion in saline environments and uptake in fresh water.[182]


The shape and energy of the land is affected to a large degree by gravitational forces. On a larger scale, the distribution of gravitational forces on the earth are uneven and influence the shape and movement of tectonic plates as well as having an influence on geomorphic processes such as orogeny and erosion. These forces govern many of the geophysical properties and distributions of ecological biomes across the Earth. On a organism scale, gravitational forces provide directional cues for plant and fungal growth (gravitropism), orientation cues for animal migrations, and influence the biomechanics and size of animals.[120] Ecological traits, such as allocation of biomass in trees during growth are subject to mechanical failure as gravitational forces influence the position and structure of branches and leaves.[183] The cardiovascular systems of all animals are functionally adapted to overcome pressure and gravitational forces that change according to the features of organisms (e.g., height, size, shape), their behavior (e.g., diving, running, flying), and the habitat occupied (e.g., water, hot deserts, cold tundra).[184]


Climatic and osmotic pressure places physiological constraints on organisms, such as flight and respiration at high altitudes, or diving to deep ocean depths. These constraints influence vertical limits of ecosystems in the biosphere as organisms are physiologically sensitive and adapted to atmospheric and osmotic water pressure differences.[120] Oxygen levels, for example, decrease with increasing pressure and are a limiting factor for life at higher altitudes.[185] Water transportation through trees is another important ecophysiological parameter where osmotic pressure gradients factor in.[186][187][188] Water pressure in the depths of oceans requires that organisms adapt to these conditions. For example, mammals, such as whales, dolphins and seals are specially adapted to deal with changes in sound due to water pressure differences.[189] Different species of hagfish provide another example of adaptation to deep-sea pressure through specialized protein adaptations.[190]

Wind and turbulence

The architecture of inflorescence in grasses is subject to the physical pressures of wind and shaped by the forces of natural selection facilitating wind-pollination (or anemophily).[191][192]

Turbulent forces in air and water have significant effects on the environment and ecosystem distribution, form and dynamics. On a planetary scale, ecosystems are affected by circulation patterns in the global trade winds. Wind power and the turbulent forces it creates can influence heat, nutrient, and biochemical profiles of ecosystems.[120] For example, wind running over the surface of a lake creates turbulence, mixing the water column and influencing the environmental profile to create thermally layered zones, partially governing how fish, algae, and other parts of the aquatic ecology are structured.[193][194] Wind speed and turbulence also exert influence on rates of evapotranspiration rates and energy budgets in plants and animals.[181][195] Wind speed, temperature and moisture content can vary as winds travel across different landfeatures and elevations. The westerlies, for example, come into contact with the coastal and interior mountains of western North America to produce a rain shadow on the leeward side of the mountain. The air expands and moisture condenses as the winds move up in elevation which can cause precipitation; this is called orographic lift. This environmental process produces spatial divisions in biodiversity, as species adapted to wetter conditions are range-restricted to the coastal mountain valleys and unable to migrate across the xeric ecosystems of the Columbia Basin to intermix with sister lineages that are segregated to the interior mountain systems.[196][197]


Mosaic fire burn.jpg Lodgepole pine cone after fire.jpg

Forest fires modify the land by leaving behind an environmental mosaic that diversifies the landscape into different seral stages and habitats of varied quality (left). Some species are adapted to forest fires, such as pine trees that open their cones only after fire exposure (right).

Plants convert carbon dioxide into biomass and emit oxygen into the atmosphere.[198] Approximately 350 million years ago (near the Devonian period) the photosynthetic process brought the concentration of atmospheric oxygen above 17%, which allowed combustion to occur.[199] Fire releases CO2 and converts fuel into ash and tar. Fire is a significant ecological parameter that raises many issues pertaining to its control and suppression in management.[200] While the issue of fire in relation to ecology and plants has been recognized for a long time,[201] Charles Cooper brought attention to the issue of forest fires in relation to the ecology of forest fire suppression and management in the 1960s.[202][203]

Fire creates environmental mosaics and a patchiness to ecosystem age and canopy structure. Native North Americans were among the first to influence fire regimes by controlling their spread near their homes or by lighting fires to stimulate the production of herbaceous foods and basketry materials.[204] The altered state of soil nutrient supply and cleared canopy structure also opens new ecological niches for seedling establishment.[205][206] Most ecosystem are adapted to natural fire cycles. Plants, for example, are equipped with a variety of adaptations to deal with forest fires. Some species (e.g., Pinus halepensis) cannot germinate until after their seeds have lived through a fire. This environmental trigger for seedlings is called serotiny.[207] Some compounds from smoke also promote seed germination.[208] Fire plays a major role in the persistence and resilience of ecosystems.[174]


Ecologists study and measure nutrient budgets to understand how these materials are regulated, flow, and recycled through the environment.[120][121][167] This research has led to an understanding that there is a global feedback between ecosystems and the physical parameters of this planet including minerals, soil, pH, ions, water and atmospheric gases. There are six major elements, including H (hydrogen), C (carbon), N (nitrogen), O (oxygen), S (sulfur), and P (phosphorus) that form the constitution of all biological macromolecules and feed into the Earth's geochemical processes. From the smallest scale of biology the combined effect of billions upon billions of ecological processes amplify and ultimately regulate the biogeochemical cycles of the Earth. Understanding the relations and cycles mediated between these elements and their ecological pathways has significant bearing toward understanding global biogeochemistry.[209]

The ecology of global carbon budgets gives one example of the linkage between biodiversity and biogeochemistry. For starters, the Earth's oceans are estimated to hold 40,000 gigatonnes (Gt) carbon, vegetation and soil is estimated to hold 2070 Gt carbon, and fossil fuel emissions are estimated to emit an annual flux of 6.3 Gt carbon.[210] At different times in the Earth's history there has been major restructuring in these global carbon budgets that was regulated to a large extent by the ecology of the land. For example, through the early-mid Eocene volcanic outgassing, the oxidation of methane stored in wetlands, and seafloor gases increased atmospheric CO2 (carbon dioxide) concentrations to levels as high as 3500 ppm.[211] In the Oligocene, from 25 to 32 million years ago, there was another significant restructuring in the global carbon cycle as grasses evolved a special type of C4 photosynthesis and expanded their ranges. This new photosynthetic pathway evolved in response to the drop in atmospheric CO2 concentrations below 550 ppm.[212] These kinds of ecosystem functions feed back significantly into global atmospheric models for carbon cycling. Loss in the abundance and distribution of biodiversity causes global carbon cycle feedbacks that are expected to increase rates of global warming in the next century.[213] The effect of global warming melting large sections of permafrost creates a new mosaic of flooded areas where decomposition results in the emission of methane (CH4). Hence, there is a relationship between global warming, decomposition and respiration in soils and wetlands producing significant climate feedbacks and altered global biogeochemical cycles.[214][215] There is concern over increases in atmospheric methane in the context of the global carbon cycle, because methane is also a greenhouse gas that is 23 times more effective at absorbing long-wave radiation than CO2 on a 100 year time scale.[216]


Early beginnings

Ecology has a complex origin due in large part to its interdisciplinary nature.[217] Ancient philosophers of Greece, including Hippocrates and Aristotle were among the first to record their observations on natural history. However, philosophers in ancient Greece viewed life as a static element that did not require an understanding of adaptation, a modern cornerstone of ecological theory.[218] Topics more familiar in the modern context, including food chains, population regulation, and productivity, did not develop until the 1700s through the published works of microscopist Antoni van Leeuwenhoek (1632–1723) and botanist Richard Bradley(1688?-1732).[6] Biogeographer Alexander von Humbolt (1769–1859) was another early pioneer in ecological thinking and was among the first to recognize ecological gradients. Humbolt alluded to the modern ecological law of species to area relationships.[219][220]

In the early 20th century, ecology was an analytical form of natural history.[221] Following in the traditions of Aristotle, the descriptive nature of natural history examined the interaction of organisms with both their environment and their community. Natural historians, including James Hutton and Jean-Baptiste Lamarck, contributed significant works that laid the foundations of the modern ecological sciences.[222] The term "ecology" (German: Oekologie) is of a more recent origin and was first coined by the German biologist Ernst Haeckel in his book Generelle Morphologie der Organismen (1866). Haeckel was a zoologist, artist, writer, and later in life a professor of comparative anatomy.[223][224]

By ecology we mean the body of knowledge concerning the economy of nature-the investigation of the total relations of the animal both to its inorganic and its organic environment; including, above all, its friendly and inimical relations with those animals and plants with which it comes directly or indirectly into contact-in a word, ecology is the study of all those complex interrelations referred to by Darwin as the conditions of the struggle of existence.

Haeckel's definition quoted in Esbjorn-Hargens[225]:6

Nicola Perscheid - Ernst Haeckel.jpg Warming,Eugen-c1900.jpg

Ernst Haeckel (left) and Eugenius Warming (right), two founders of ecology

Opinions differ on who was the founder of modern ecological theory. Some mark Haeckel's definition as the beginning,[226] others say it was Eugenius Warming with the writing of Oecology of Plants: An Introduction to the Study of Plant Communities (1895).[227] Ecology may also be thought to have begun with Carl Linnaeus' research principals on the economy of nature that matured in the early 18th century.[81][228] He founded an early branch of ecological study he called the economy of nature.[81] The works of Linnaeus influenced Darwin in The Origin of Species where he adopted the usage of Linnaeus' phrase on the economy or polity of nature.[223] Linnaeus was the first to frame the balance of nature as a testable hypothesis. Haeckel, who admired Darwin's work, defined ecology in reference to the economy of nature which has led some to question if ecology is synonymous with Linnaeus' concepts for the economy of nature.[228]

The modern synthesis of ecology is a young science, which first attracted substantial formal attention at the end of the 19th century (around the same time as evolutionary studies) and become even more popular during the 1960s environmental movement,[222] though many observations, interpretations and discoveries relating to ecology extend back to much earlier studies in natural history. For example, the concept on the balance or regulation of nature can be traced back to Herodotos (died c. 425 BC) who described an early account of mutualism along the Nile river where crocodiles open their mouths to beneficially allow sandpipers safe access to remove leeches.[217] In the broader contributions to the historical development of the ecological sciences, Aristotle is considered one of the earliest naturalists who had an influential role in the philosophical development of ecological sciences. One of Aristotle's students, Theophrastus, made astute ecological observations about plants and posited a philosophical stance about the autonomous relations between plants and their environment that is more in line with modern ecological thought. Both Aristotle and Theophrastus made extensive observations on plant and animal migrations, biogeography, physiology, and their habits in what might be considered an analog of the modern ecological niche.[229][230] Hippocrates, another Greek philosopher, is also credited with reference to ecological topics in its earliest developments.[6]

The layout of the first ecological experiment, noted by Charles Darwin in The Origin of Species, was studied in a grass garden at Woburn Abbey in 1817. The experiment studied the performance of different mixtures of species planted in different kinds of soils.[231][232]

From Aristotle to Darwin the natural world was predominantly considered static and unchanged since its original creation. Prior to The Origin of Species there was little appreciation or understanding of the dynamic and reciprocal relations between organisms, their adaptations and their modifications to the environment.[233][225] While Charles Darwin is most notable for his treatise on evolution,[234] he is also one of the founders of soil ecology.[235] In The Origin of Species Darwin also made note of the first ecological experiment that was published in 1816.[231] In the science leading up to Darwin the notion of evolving species was gaining popular support. This scientific paradigm changed the way that researchers approached the ecological sciences.[236]

Nowhere can one see more clearly illustrated what may be called the sensibility of such an organic complex,--expressed by the fact that whatever affects any species belonging to it, must speedily have its influence of some sort upon the whole assemblage. He will thus be made to see the impossibility of studying any form completely, out of relation to the other forms,--the necessity for taking a comprehensive survey of the whole as a condition to a satisfactory understanding of any part.

Stephen Forbes (1887)[237]

After the turn of 20th century

Some suggest that the first ecological text (Natural History of Selborne) was published in 1789, by Gilbert White (1720–1793).[238] The first American ecology book was published in 1905 by Frederic Clements.[239] In his book, Clements forwarded the idea of plant communities as a superorganism. This publication launched a debate between ecological holism and individualism that lasted until the 1970s. The Clements superorganism concept proposed that ecosystems progress through regular and determined stages of seral development that are analogous to developmental stages of an organism whose parts function to maintain the integrity of the whole. The Clementsian paradigm was challenged by Henry Gleason.[240] According to Gleason, ecological communities develop from the unique and coincidental association of individual organisms. This perceptual shift placed the focus back onto the life histories of individual organisms and how this relates to the development of community associations.[241]

The Clementsian superorganism theory has not been completely rejected, but some suggest it was an overextended application of holism.[115] Holism remains a critical part of the theoretical foundation in contemporary ecological studies.[163] Holism was first introduced in 1926 by a polarizing historical figure, a South African General named Jan Christian Smuts. Smuts was inspired by Clement's superorganism theory as he developed and published on the concept of holism, which contrasts starkly against his racial political views as the father of apartheid.[242] Around the same time, Charles Elton pioneered the concept of food chains in his classical book "Animal Ecology".[86] Elton[86] defined ecological relations using concepts of food chains, food cycles, food size, and described numerical relations among different functional groups and their relative abundance. Elton's 'food cycle' was replaced by 'food web' in a subsequent ecological text.[243]

Ecology has developers in many nations, including Russia's Vladimir Vernadsky and his founding of the biosphere concept in the 1920s[244] or Japan's Kinji Imanishi and his concepts of harmony in nature and habitat segregation in the 1950s.[245] The scientific recognition or importance of contributions to ecology from other cultures is hampered by language and translation barriers.[244]

See also



  1. ^ "Millennium Ecosystem Assessment - Synthesis Report". United Nations. 2005. Retrieved 4 February 2010. 
  2. ^ de Groot, R. S.; Wilson, M. A.; Boumans, R. M. J. (2002). "A typology for the classification, description and valuation of ecosystem functions, goods and services". Ecological Economics 41 (3): 393–408. doi:10.1016/S0921-8009(02)00089-7.$FILE/deGroot%20et%20al.pdf. 
  3. ^ Aguirre, A.A. (2009). "Biodiversity and Human Health". EcoHealth 6: 153. doi:10.1007/s10393-009-0242-0. 
  4. ^ Stadler, B.; Michalzik, B.; Müller, T. (1998). "Linking aphid ecology with nutrient fluxes in a coniferous forest". Ecology 79 (5): 1514–25. doi:10.1890/0012-9658(1998)079[1514:LAEWNF]2.0.CO;2. ISSN 0012-9658. 
  5. ^ Humphreys, N. J.; Douglas, A. E. (1997). "Partitioning of Symbiotic Bacteria between Generations of an Insect: a Quantitative Study of a Buchnera sp. in the Pea Aphid (Acyrthosiphon pisum) Reared at Different Temperatures". Applied and Environmental Microbiology 63 (8): 3294–6. PMC 1389233. PMID 16535678. 
  6. ^ a b c d e f g h i Template:Ref book
  7. ^ a b O'Neill, D. L.; Deangelis, D. L.; Waide, J. B.; Allen, T. F. H. (1986). A hierarchical concept of ecosystems. Princeton University Press. p. 253. ISBN 0-691-08436-X. 
  8. ^ Nachtomy, Ohad; Shavit, Ayelet; Smith, Justin (2002). "Leibnizian organisms, nested individuals, and units of selection". Theory in Biosciences 121 (2): 205. doi:10.1007/s12064-002-0020-9. 
  9. ^ a b Holling, C. S. (2004). "Understanding the Complexity of Economic, Ecological, and Social Systems". Ecosystems 4 (5): 390–405. doi:10.1007/s10021-001-0101-5. 
  10. ^ Gotts, N. N. (2007). "Resilience, panarchy, and world-systems analysis". Ecology and Society 12 (1): 24. 
  11. ^ Levin, S. A. (1999). Fragile dominion: Complexity and the commons. Reading, Massachusetts: Perseus Books. ISBN 9780738203195. 
  12. ^ Noss, R. F.; Carpenter, A. Y. (1994). Saving nature's legacy: protecting and restoring biodiversity. Island Press. p. 443. ISBN 9781559632485. 
  13. ^ Noss, R. F. (1990). "Indicators for Monitoring Biodiversity: A Hierarchical Approach". Conservation Biology 4 (4): 355–364. doi:10.1111/j.1523-1739.1990.tb00309.x. JSTOR 2385928. 
  14. ^ a b Scholes, R. J. et al. (2008). "Toward a global biodiversity observing system". Science 321 (5892): 1044–5. doi:10.1126/science.1162055. PMID 18719268. 
  15. ^ a b c d e f Wilson, E. O. (2000). "A Global Biodiversity Map". Science 289 (5488): 2279. doi:10.1126/science.289.5488.2279. PMID 11041790. 
  16. ^ Purvis, A.; Hector, A. (2000). "Getting the measure of biodiversity". Nature 405 (6783): 212–8. doi:10.1038/35012221. PMID 10821281. Retrieved 2010-03-16. 
  17. ^ Ostfeld, R. S. (2009). "Biodiversity loss and the rise of zoonotic pathogens". Clinical Microbiology and Infection 15 (s1): 40–3. doi:10.1111/j.1469-0691.2008.02691.x. PMID 19220353. 
  18. ^ Tierney, G. L. et al. (2009). "Monitoring and evaluating the ecological integrity of forest ecosystems". Frontiers in Ecology and the Environment 7 (6): 308–316. doi:10.1890/070176. Retrieved 2010-03-16. 
  19. ^ Wilcove, D. S.; Wikelski, M. (2008). "Going, Going, Gone: Is Animal Migration Disappearing". PLoS Biol 6 (7): e188. doi:10.1371/journal.pbio.0060188. PMC 2486312. PMID 18666834. 
  20. ^ a b Svenning, Jens-Christian; Condi, R. (2008). "Biodiversity in a warmer world". Science 322 (5899): 206–7. doi:10.1126/science.1164542. PMID 18845738. 
  21. ^ Ceballos, G.; Ehrlich, P. R. (2002). "Mammal Population Losses and the Extinction Crisis". Science 296 (5569): 904–907. Bibcode 2002Sci...296..904C. doi:10.1126/science.1069349. PMID 11988573. Retrieved 2010-03-16. 
  22. ^ Palumbi, S. R. et al. (2009). "Managing for ocean biodiversity to sustain marine ecosystem services". Frontiers in Ecology and the Environment 7 (4): 204–211. doi:10.1890/070135. 
  23. ^ Hammond, H. (2009). Maintaining whole systems on the Earth's crown: Ecosystem-based conservation planning for the Boreal forest. Slocan Park, BC: Silva Forest Foundation. p. 380. ISBN 978-0-9734779-0-0. 
  24. ^ a b c Whittaker, R. H.; Levin, S. A.; Root, R. B. (1973). "Niche, Habitat, and Ecotope". The American Naturalist 107 (955): 321–338. doi:10.1086/282837. JSTOR 2459534?. 
  25. ^ Beyer, H. L. et al. (2010). "The interpretation of habitat preference metrics under use–availability designs". Phil. Trans. R. Soc. B 365 (1550): 2245–54. doi:10.1098/rstb.2010.0083. PMC 2894962. PMID 20566501. 
  26. ^ Schoener, T. W. (1975). "Presence and absence of habitat shift in some widespread lizard species". Ecological Monographs 45 (3): 233–258. doi:10.2307/1942423. JSTOR 1942423. 
  27. ^ Vitt, L. J.; Caldwell, J. P.; Zani, P. A.; Titus, T. A. (1997). "The role of habitat shift in the evolution of lizard morphology: evidence from tropical Tropidurus". PNAS 94 (8): 3828–3832. doi:10.1073/pnas.94.8.3828. PMC 20526. PMID 9108063. 
  28. ^ Kiessling, W.; Simpson, C.; Foote, M. (2009). "Reefs as Cradles of Evolution and Sources of Biodiversity in the Phanerozoic". Science 327 (5962): 196–8. Bibcode 2010Sci...327..196K. doi:10.1126/science.1182241. PMID 20056888. 
  29. ^ a b c Laland, K. N.; Odling-Smee, F.J.; Feldman, M.W. (1999). "Evolutionary consequences of niche construction and their implications for ecology". Proc. Natl. Acad. Sci. U.S.A. 96 (18): 10242–7. Bibcode 1999PNAS...9610242L. doi:10.1073/pnas.96.18.10242. PMC 17873. PMID 10468593. 
  30. ^ a b Hughes, D. P.; Pierce, N. E.; Boomsma, J. J. (2008). "Social insect symbionts: evolution in homeostatic fortresses". Trends in Ecology & Evolution 23 (12): 672–7. doi:10.1016/j.tree.2008.07.011. PMID 18951653. 
  31. ^ a b c Wiens, J. J.; Graham, C. H. (2005). "Niche Conservatism: Integrating Evolution, Ecology, and Conservation Biology". Annual Review of Ecology, Evolution, and Systematics 36: 519–539. doi:10.1146/annurev.ecolsys.36.102803.095431. 
  32. ^ Hutchinson, G. E. (1957). A Treatise on Limnology.. New York: Wiley. p. 1015. ISBN 0471425729. 
  33. ^ a b Hutchinson, G. E. (1957). "Concluding remarks". Cold Spring Harb Symp Quant Biol 22: 415–427. doi:10.1101/SQB.1957.022.01.039. 
  34. ^ a b c Begon, M.; Townsend, C. R.; Harper, J. L. (2005). Ecology: From individuals to ecosystems. (4th ed.). Wiley-Blackwell. p. 752. ISBN 1405111178. 
  35. ^ D. L., Hardesty (1975). "The Niche Concept: Suggestions for Its Use in Human Ecology". Human Ecology 3 (2): 71–85. doi:10.1007/BF01552263. JSTOR 4602315. 
  36. ^ Pearman, P. B.; Guisan, A.; Broennimann, O.; Randin, C. F. (2008). "Niche dynamics in space and time". Trends in Ecology & Evolution 23 (3): 149–158. doi:10.1016/j.tree.2007.11.005. PMID 18289716. 
  37. ^ McGill, B. J.; Enquist, B. J.; Weiher, E.; Westoby, M. (2006). "Rebuilding community ecology from functional traits". Trends in Ecology and Evolution 21 (4): 178–185. doi:10.1016/j.tree.2006.02.002. PMID 16701083. 
  38. ^ Hardin, G. (1960). "The competitive exclusion principal". Science 131 (3409): 1292–7. Bibcode 1960Sci...131.1292H. doi:10.1126/science.131.3409.1292. PMID 14399717. 
  39. ^ Scheffer, M.; van Nes, E. H. (2006). "Self-organized similarity, the evolutionary emergence of groups of similar species". Proceedings of the National Academy of Science 103 (16): 6230–6235. Bibcode 2006PNAS..103.6230S. doi:10.1073/pnas.0508024103. ISBN 0508024103. 
  40. ^ Hastings, A. B. et al. (2007). "Ecosystem engineering in space and time". Ecology Letters 10 (2): 153–164. doi:10.1111/j.1461-0248.2006.00997.x. PMID 17257103. 
  41. ^ Jones, Clive G.; Lawton, John H.; Shachak, Moshe (1994). "Organisms as ecosystem engineers". Oikos 69 (3): 373–386. doi:10.2307/3545850. JSTOR 3545850. 
  42. ^ Wright, J.P.; Jones, C.G. (2006). "The Concept of Organisms as Ecosystem Engineers Ten Years On: Progress, Limitations, and Challenges". BioScience 56 (3): 203–9. doi:10.1641/0006-3568(2006)056[0203:TCOOAE]2.0.CO;2. ISSN 0006-3568. 
  43. ^ Day, R. L.; Laland, K. N.; Odling-Smee, J. (2003). "Rethinking Adaptation: the niche-construction perspective". Perspectives in Biology and Medicine 46 (1): 80–95. doi:10.1353/pbm.2003.0003. PMID 12582272. 
  44. ^ Palmer, M.; White, P. S. (1994). "On the existence of ecological communities". Journal of Vegetation Sciences 5 (2): 279–282. doi:10.2307/3236162. JSTOR 3236162. 
  45. ^ Prentice, I. C. et al. (1992). "Special Paper: A Global Biome Model Based on Plant Physiology and Dominance, Soil Properties and Climate". Journal of Biogeography 19 (2): 117–134. doi:10.2307/2845499. JSTOR 2845499. 
  46. ^ Turnbaugh, P. J. et al. (2007). "The Human Microbiome Project". Nature 449 (7164): 804–810. Bibcode 2007Natur.449..804T. doi:10.1038/nature06244. PMID 17943116. 
  47. ^ DeLong, E. F. (2009). "The microbial ocean from genomes to biomes". Nature 459 (7244): 200–6. Bibcode 2009Natur.459..200D. doi:10.1038/nature08059. PMID 19444206. 
  48. ^ Igamberdiev, Abir U.; Lea, P. J. (2006). "Land plants equilibrate O2 and CO2 concentrations in the atmosphere". Photosynthesis Research 87 (2): 177–194. doi:10.1007/s11120-005-8388-2. PMID 16432665. 
  49. ^ Lovelock, J.; Margulis, Lynn (1973). "Atmospheric homeostasis by and for the biosphere: the Gaia hypothesis". Tellus 26: 2–10. Bibcode 1974Tell...26....2L. doi:10.1111/j.2153-3490.1974.tb01946.x. 
  50. ^ a b c Lovelock, J. (2003). "The living Earth". Nature 426 (6968): 769–770. doi:10.1038/426769a. PMID 14685210. 
  51. ^ Waples, R. S.; Gaggiotti, O. (2006). "What is a population? An empirical evaluation of some genetic methods for identifying the number of gene pools and their degree of connectivity". Molecular Ecology 15 (6): 1419–39. doi:10.1111/j.1365-294X.2006.02890.x. PMID 16629801. 
  52. ^ a b c Turchin, P. (2001). "Does Population Ecology Have General Laws?". Oikos 94 (1): 17–26. doi:10.1034/j.1600-0706.2001.11310.x. 
  53. ^ Johnson, J. B.; Omland, K. S. (2004). "Model selection in ecology and evolution". Trends in Ecology and Evolution 19 (2): 101–8. doi:10.1016/j.tree.2003.10.013. PMID 16701236. 
  54. ^ a b Vandermeer, J. H.; Goldberg, D. E. (2003). Population ecology: First principles. Woodstock, Oxfordshire: Princeton University Press. ISBN 0-691-11440-4. 
  55. ^ Berryman, A. A. (1992). "The Origins and Evolution of Predator-Prey Theory". Ecology 73 (5): 1530–5. doi:10.2307/1940005. JSTOR 1940005. 
  56. ^ Levins, R. (1969). "Some demographic and genetic consequences of environmental heterogeneity for biological control". Bulletin of the Entomological Society of America 15: 237–240. ISBN 9780231126809. 
  57. ^ Levins, R. (1970). Gerstenhaber, M.. ed. Extinction. In: Some Mathematical Questions in Biology. pp. 77–107. ISBN 9780821811528. 
  58. ^ Smith, M. A.; Green, D. M. (2005). "Dispersal and the metapopulation paradigm in amphibian ecology and conservation: are all amphibian populations metapopulations?". Ecography 28 (1): 110–128. doi:10.1111/j.0906-7590.2005.04042.x. 
  59. ^ Hanski, I. (1998). "Metapopulation dynamics". Nature 396 (6706): 41–9. Bibcode 1998Natur.396...41H. doi:10.1038/23876. 
  60. ^ Nebel, S. (2010). "Animal migration". Nature Education Knowledge 10 (1): 29. 
  61. ^ Clark, J. S.; Fastie, C.; Hurtt, G.; Jackson, S. T.; Johnson, C.; King, G. A.; et al., M.; Lynch, J. et al. (1998). "Reid's Paradox of Rapid Plant Migration". BioScience 48 (1): 13–24. doi:10.2307/1313224. 
  62. ^ Template:Ref book
  63. ^ Hanski, I.; Gaggiotti, O. E., eds (2004). Ecology, genetics and evolution of metapopulations.. Burlington, MA: Elsevier Academic Press. ISBN 0-12-323448-4.,+genetics,+and+evolution+of+metapopulations&dq=ecology,+genetics,+and+evolution+of+metapopulations&cd=1. 
  64. ^ MacKenzie, D. I. (2006). Occupancy Estimation and Modeling: Inferring patterns and dynamics of species occurrence.. London, UK: Elsevier Academic Press. p. 324. ISBN 978-0-12-088766-8. 
  65. ^ Johnson, M. T.; Strinchcombe, J. R. (2007). "An emerging synthesis between community ecology and evolutionary biology". Trends in Ecology and Evolution 22 (5): 250–7. doi:10.1016/j.tree.2007.01.014. PMID 17296244. 
  66. ^ Brinson, M. M.; Lugo, A. E.; Brown, S (1981). "Primary Productivity, Decomposition and Consumer Activity in Freshwater Wetlands". Annual Review of Ecology and Systematics 12: 123–161. doi:10.1146/ 
  67. ^ a b Davic, R. D.; Welsh, H. H. (2004). "On the Ecological Role of Salamanders". Annual Review of Ecology and Systematics 35: 405–434. doi:10.1146/annurev.ecolsys.35.112202.130116. 
  68. ^ Paine, R. T. (1980). "Food Webs: Linkage, Interaction Strength and Community Infrastructure". Journal of Animal Ecology 49 (3): 667–685. JSTOR 4220. 
  69. ^ Abrams, P. A. (1993). "Effect of Increased Productivity on the Abundances of Trophic Levels". The American Naturalist 141 (3): 351–371. doi:10.1086/285478. JSTOR 2462676?. 
  70. ^ a b Tansley, A. G. (1935). "The Use and Abuse of Vegetational Concepts and Terms". Ecology 16 (3): 284–307. doi:10.2307/1930070. JSTOR 1930070. 
  71. ^ Marsh, G. P. (1864). Man and nature: Physical geography as modified by human action.. Cambridge, Massachusetts, USA: Belknap Press. p. 560. 
  72. ^ a b O'Neil, R. V. (2001). "Is it time to bury the ecosystem concept? (With full military honors, of course!)". Ecology 82 (12): 3275–3284. doi:10.1890/0012-9658(2001)082[3275:IITTBT]2.0.CO;2. ISSN 0012-9658. 
  73. ^ Levin, S. A. (1998). "Ecosystems and the Biosphere as Complex Adaptive Systems". Ecosystems 1 (5): 431–6. doi:10.1007/s100219900037. 
  74. ^ Pimm, S. (2002). Food webs. University of Chicago Press. p. 258. ISBN 9780226668321. 
  75. ^ a b Pimm, S. L.; Lawton, J. H.; Cohen, J. E. (1991). "Food web patterns and their consequences". Nature 350 (6320): 669–674. Bibcode 1991Natur.350..669P. doi:10.1038/350669a0. 
  76. ^ Worm, B.; Duffy, J.E. (2003). "Biodiversity, productivity and stability in real food webs". Trends in Ecology and Evolution 18 (12): 628–632. doi:10.1016/j.tree.2003.09.003. 
  77. ^ McCann, K. (2007). "Protecting biostructure". Nature 446 (7131): 29–29. Bibcode 2007Natur.446...29M. doi:10.1038/446029a. PMID 17330028. 
  78. ^ Wilbur, H. W. (1997). "Experimental ecology of food webs: Complex systems in temporary ponds" (PDF). Ecology 78 (8): 2279–2302. doi:10.1890/0012-9658(1997)078[2279:EEOFWC]2.0.CO;2. ISSN 0012-9658. 
  79. ^ Emmerson, M; Yearsley, J. M. (2004). "Weak interactions, omnivory and emergent food-web properties". Proc. R. Soc. Lond. B 271 (1537): 397–405. doi:10.1098/rspb.2003.2592. 
  80. ^ Krause, A. E.; Frank, K. A.; Mason, D. M.; Ulanowicz, R. E.; Taylor, W. W. (2003). "Compartments revealed in food-web structure". Nature 426 (6964): 282–285. Bibcode 2003Natur.426..282K. doi:10.1038/nature02115. PMID 14628050. 
  81. ^ a b c Egerton, Frank N. (2007). "Understanding Food Chains and Food Webs, 1700–1970". Bulletin of the Ecological Society of America 88: 50–69. doi:10.1890/0012-9623(2007)88[50:UFCAFW]2.0.CO;2. ISSN 0012-9623. 
  82. ^ Shurin, J. B.; Gruner, D. S.; Hillebrand, H. (2006). "All wet or dried up? Real differences between aquatic and terrestrial food webs". Proc. R. Soc. B 273 (1582): 1–9. doi:10.1098/rspb.2005.3377. PMC 1560001. PMID 16519227. 
  83. ^ Edwards, J.; Fraser, K. (1983). "Concept maps as reflectors of conceptual understanding". Research in science education 13: 19–26. Bibcode 1983RScEd..13...19E. doi:10.1007/BF02356689. 
  84. ^ Hairston, N. G.; Hairston, N. G. (1993). "Cause-effect relationships in energy flow, trophic structure, and interspecific interactions". The American Naturalist 142 (3): 379–411. doi:10.1086/285546. 
  85. ^ Duffy, J. E. et al. (2007). "The functional role of biodiversity in ecosystems: incorporating trophic complexity". Ecology Letters 10 (6): 522–538. doi:10.1111/j.1461-0248.2007.01037.x. PMID 17498151. 
  86. ^ a b c Elton, C. S. (1927). Animal Ecology. London, UK.: Sidgwick and Jackson. ISBN 0226206394. 
  87. ^ Davic, R. D. (2003). "Linking keystone species and functional groups: a new operational definition of the keystone species concept". Conservation Ecology 7 (1): r11. 
  88. ^ Oksanen, L. (1991). "Trophic levels and trophic dynamics: A consensus emerging?". Trends in Ecology and Evolution 6 (2): 58–60. doi:10.1016/0169-5347(91)90124-G. PMID 21232425. 
  89. ^ Loehle, C.; Pechmann, Joseph H. K. (1988). "Evolution: The Missing Ingredient in Systems Ecology". The American Naturalist 132 (9): 884–899. doi:10.1086/284895. JSTOR 2462267. 
  90. ^ Ulanowicz, R. E.; Kemp, W. Michael (1979). "Toward Canonical Trophic Aggregations". The American Naturalist 114 (6): 871–883. doi:10.1086/283534. JSTOR 2460557. 
  91. ^ Li, B. (2000). "Why is the holistic approach becoming so important in landscape ecology?". Landscape and Urban Planning 50 (1–3): 27–41. doi:10.1016/S0169-2046(00)00078-5. 
  92. ^ Polis, G. A.; Strong, D. R. (1996). "Food web complexity and community dynamics". The American Naturalist 147 (5): 813–846. doi:10.1086/285880. 
  93. ^ Thompson, R. M.; Hemberg, M.; Starzomski, B. M.; Shurin, J. B. (2007). "Trophic levels and trophic tangles: The prevalence of omnivory in real food webs". Ecology 88 (3): 612–617. doi:10.1890/05-1454. PMID 17503589. 
  94. ^ Fischer, J.; Lindenmayer, D. B.; Manning, A. D. (2006). "Biodiversity, ecosystem function, and resilience: ten guiding principles for commodity production landscapes". Frontiers in Ecology and the Environment 4 (2): 80–86. doi:10.1890/1540-9295(2006)004[0080:BEFART]2.0.CO;2. ISSN 1540-9295. 
  95. ^ Libralato, S.; Christensen, V.; Pauly, D. (2006). "A method for identifying keystone species in food web models". Ecological Modelling 195 (3–4): 153–171. doi:10.1016/j.ecolmodel.2005.11.029. 
  96. ^ a b Mills, L.S.; Soule, M.E.; Doak, D.F. (1993). "The Keystone-Species Concept in Ecology and Conservation". BioScience 43 (4): 219–224. doi:10.2307/1312122. JSTOR 1312122. 
  97. ^ Anderson, P.K. (1995). "Competition, predation, and the evolution and extinction of Stellar's sea cow, Hydrodamalis gigas". Marine Mammal Science 11 (3): 391–4. doi:10.1111/j.1748-7692.1995.tb00294.x. 
  98. ^ Polis, G.A. et al. (2000). "When is a trophic cascade a trophic cascade?". Trends in Ecology and Evolution 15 (11): 473–5. doi:10.1016/S0169-5347(00)01971-6. PMID 11050351. 
  99. ^ Coleman, D. C.; Odum, E. P.; Crossley, D. A. (1992). "Soil biology, soil ecology, and global change". Biology and Fertility of Soils 14 (2): 104–111. doi:10.1007/BF00336258. 
  100. ^ Coleman, D. C.; Corssley, D. A.; Hendrix, P. F. (2004). Fundamentals of soil ecology (2nd ed.). Academic Press. ISBN 0121797260. 
  101. ^ Lecerf, A.; Dobson, M.; Dang, C. K.; Chauvet, E (2005). "Riparian plant species loss alters trophic dynamics in detritus-based stream ecosystems". Oecologia 146 (3): 432–442. doi:10.1007/s00442-005-0212-3. PMID 16096846. 
  102. ^ a b Wilkinson, M. T.; Richards, P. J.; Humphreys, G. S. (2009). "Breaking ground: Pedological, geological, and ecological implications of soil bioturbation". Earth-Science Reviews 97 (1–4): 257–272. doi:10.1016/j.earscirev.2009.09.005. 
  103. ^ Hasiotis, S. T. (2003). "Complex ichnofossils of solitary and social soil organisms: understanding their evolution and roles in terrestrial paleoecosystems". Palaeogeography, Palaeoclimatology, Palaeoecology 192 (2): 259–320. doi:10.1016/S0031-0182(02)00689-2. 
  104. ^ Levin, S. A. (2000). "Multiple scales and the maintenance of biodiversity". Ecosystems 3 (6): 498–506. doi:10.1007/s100210000044. 
  105. ^ Novikoff, AB (1945). "The concept of integrative levels and biology". Science 101 (2618): 209–215. Bibcode 1945Sci...101..209N. doi:10.1126/science.101.2618.209. PMID 17814095. 
  106. ^ Schneider, D. D. (2001). "The Rise of the Concept of Scale in Ecology". BioScience 51 (7): 545–553. doi:10.1641/0006-3568(2001)051[0545:TROTCO]2.0.CO;2. ISSN 0006-3568. Retrieved 2010-03-16. 
  107. ^ Molnar, J.; Marvier, M.; Kareiva, P. (2004). "The sum is greater than the parts". Conservation Biology 18 (6): 1670–1. doi:10.1111/j.1523-1739.2004.00l07.x. 
  108. ^ Loehle, C. (2004). "Challenges of ecological complexity". Ecological complexity 1 (1): 3–6. doi:10.1016/j.ecocom.2003.09.001. 
  109. ^ a b Odum, E. P. (1977). "The emergence of ecology as a new integrative discipline". Science 195 (4284): 1289–93. Bibcode 1977Sci...195.1289O. doi:10.1126/science.195.4284.1289. PMID 17738398. 
  110. ^ Scheffer, M.; Carpenter, S.; Foley, J. A.; Walker, B.; Walker, B (2001). "Catastrophic shifts in ecosystems". Nature 413 (6856): 591–596. Bibcode 2001Natur.413..591S. doi:10.1038/35098000. PMID 11595939. 
  111. ^ "Welcome to ILTER — ILTER". International Long Term Ecological Research. Retrieved 2010-03-16. 
  112. ^ Silverton, J. et al. (2006). "The Park Grass Experiment 1856–2006: its contribution to ecology". Journal of Ecology 94 (4): 801–814. doi:10.1111/j.1365-2745.2006.01145.x. 
  113. ^ "Hubbard Brook Ecosystem Study Front Page". Retrieved 2010-03-16. 
  114. ^ Mikkelson, G. M. (In Press.). Skipper, R. A.; Ankeny, L.; Allen, C. et al.. eds. Part-whole Relationships and the unity of ecology. In, Philosophy across the Life Sciences.. Cambridge, MA.: MIT Press.. 
  115. ^ a b Wilson, D. S. (1988). "Holism and Reductionism in Evolutionary Ecology". Oikos 53 (2): 269–273. doi:10.2307/3566073. JSTOR 3566073. 
  116. ^ Miles, D. B.; Dunham, A. E. (1993). "Historical Perspectives in Ecology and Evolutionary Biology: The Use of Phylogenetic Comparative Analyses". Annual Review of Ecology and Systematics 24: 587–619. doi:10.1146/ 
  117. ^ Trends in Ecology and Evolution. Official Cell Press page the journal. Elsevier, Inc. 2009
  118. ^ Vrba, E. S.; Eldredge, N. (1984). "Individuals, Hierarchies and Processes: Towards a More Complete Evolutionary Theory". Paleobiology 10 (2): 146–171. JSTOR 2400395. 
  119. ^ Gould, S.J.; Lloyd, E.A. (1999). "Individuality and adaptation across levels of selection: How shall we name and generalize the unit of Darwinism?". Proc. Natl. Acad. Sci. U.S.A. 96 (21): 11904–9. Bibcode 1999PNAS...9611904G. doi:10.1073/pnas.96.21.11904. PMC 18385. PMID 10518549. 
  120. ^ a b c d e f g h i Allee, W.C.; Park, O.; Emerson, A. E.; Park, T.; Schmidt, K.P. (1949). Principles of animal ecology. W. B. Sunders, Co.. p. 837. ISBN 0721611206. 
  121. ^ a b c d e Rickleffs, Robert, E. (1996). The Economy of Nature. University of Chicago Press. p. 678. ISBN 0716738473. 
  122. ^ Stuart-Fox, D.; Moussalli, A. (2008). "Selection for Social Signalling Drives the Evolution of Chameleon Colour Change". PLoS Biol 6 (1): e25. doi:10.1371/journal.pbio.0060025. PMC 2214820. PMID 18232740. 
  123. ^ Karban, R. (2008). "Plant behaviour and communication". Ecology Letters 11 (7): 727–739. doi:10.1111/j.1461-0248.2008.01183.x. PMID 18400016. 
  124. ^ Tinbergen, N. (1963). "On aims and methods of ethology" (PDF). Zeitschrift für Tierpsychologie 20 (4): 410–433. doi:10.1111/j.1439-0310.1963.tb01161.x. 
  125. ^ Hamner, W. M. (1985). "The importance of ethology for investigations of marine zooplankton". Bulletin of Marine Science 37 (2): 414–424. 
  126. ^ a b Strassmann, J. E.; Zhu, Y; Queller, DC (2000). "Altruism and social cheating in the social amoeba Dictyostelium discoideum". Nature 408 (6815): 965–967. doi:10.1038/35050087. PMID 11140681. 
  127. ^ Sakurai, K. (1985). "An attelabid weevil (Euops splendida) cultivates fungi". Journal of Ethology 3 (2): 151–156. doi:10.1007/BF02350306. 
  128. ^ Anderson, J. D. (1961). "The courtship behaviour of Ambystoma macrodactylum croceum". Copeia 2 (2): 132–139. JSTOR 1439987. 
  129. ^ "Behavioral Ecology". International Society for Behavioral Ecology. Retrieved 15 April 2011. 
  130. ^ Gould, Stephen, J.; Vrba, Elizabeth, S. (1982). "Exaptation-a missing term in the science of form". Paleobiology 8 (1): 4–15. 
  131. ^ Ives, A. R.; Cardinale, B. J.; Snyder, W. E. (2004). "A synthesis of subdisciplines: predator–prey interactions, and biodiversity and ecosystem functioning". Ecology Letters 8 (1): 102–116. doi:10.1111/j.1461-0248.2004.00698.x. 
  132. ^ Krebs, J. R.; Davies, N. B. (1993). An Introduction to Behavioural Ecology. Wiley-Blackwell. p. 432. ISBN 978-0632035465. 
  133. ^ Webb, J. K.; Pike, D. A.; Shine, R. (2010). "Olfactory recognition of predators by nocturnal lizards: safety outweighs thermal benefits". Behavioural Ecology 21 (1): 72–77. doi:10.1093/beheco/arp152. 
  134. ^ Cooper, W. E.; Frederick, W. G. (2010). "Predator lethality, optimal escape behavior, and autotomy". Behavioral Ecology 21 (1): 91–96. doi:10.1093/beheco/arp151. 
  135. ^ Eastwood, R. (2004). "Successive replacement of tending ant species at aggregations of scale insects (Hemiptera: Margarodidae and Eriococcidae) on Eucalyptus in south-east Queensland". Australian Journal of Entomology 43: 1–4. doi:10.1111/j.1440-6055.2003.00371.x. 
  136. ^ Kodric-Brown, A.; Brown, J. H. (1984). "Truth in advertising: The kinds of traits favored by sexual selection". The American Naturalist 124 (3): 309–323. doi:10.1086/284275. 
  137. ^ Sherman, P. W.; Lacey, E. A.; Reeve, H. K.; Keller, L. (1995). "The eusociality continuum" (PDF). Behavioural Ecology 6 (1): 102–8. 
  138. ^ Wilson, D. S.; Wilson, E. O. (December 2007). "Rethinking the theoretical foundation of sociobiology". The Quarterly Review of Biology 82 (4): 327–348. doi:10.1086/522809. PMID 18217526. 
  139. ^ Page, R. d. m. (1991). "Clocks, Clades, and Cospeciation: Comparing Rates of Evolution and Timing of Cospeciation Events in Host-Parasite Assemblages". Systematic Zoology 40 (2): 188–198. doi:10.2307/2992256. JSTOR 2992256. 
  140. ^ Kiers, E. T.; van der Heijden, M. G. A. (2006). "Mutualistic stability in the arbuscular mycorrhizal symbiosis: Exploring hypotheses of evolutionary cooperation". Ecology 87 (7): 1627–36. doi:10.1890/0012-9658(2006)87[1627:MSITAM]2.0.CO;2. ISSN 0012-9658. PMID 16922314. 
  141. ^ Aanena, D. K.; Hoekstra, R. F. (2007). "The evolution of obligate mutualism: if you can't beat 'em, join 'em". Trends in Ecology & Evolution 22 (10): 506–9. doi:10.1016/j.tree.2007.08.007. PMID 17825952. 
  142. ^ Boucher, D. H.; James, S.; Keeler, K. H. (1982). "The Ecology of Mutualism". Annual Review of Ecology and Systematics 13: 315–347. doi:10.1146/ 
  143. ^ Herre, E. A.; Knowlton, N.; Mueller, U. G.; Rehner, S. A. (1999). "The evolution of mutualisms: Exploring the paths between conflict and cooperation". Trends in Ecology and Evolution 14 (2): 49–53. doi:10.1016/S0169-5347(98)01529-8. PMID 10234251. 
  144. ^ Gilbert, F. S. (1990). Insect life cycles: genetics, evolution, and co-ordination. New York: Springer-Verlag. p. 258. ISBN 0387195505. 
  145. ^ Bronstein J.L. 2001. The exploitation of mutualisms. Ecology Letters 4: 277-287.
  146. ^ Irwin RE, JL Bronstein, JS Manson, and L Richardson 2010. Nectar Robbing: Ecological and Evolutionary Perspectives. Ann. Rev. Ecol. Evol. Syst. 41: 271-292.
  147. ^ a b Parenti, L. R.; Ebach, M. C. (2009). Comparative biogeography: Discovering and classifying biogeographical patterns of a dynamic Earth.. London, England: University of California Press. ISBN 978-0-520-25945-4. 
  148. ^ Journal of Biogeography
  149. ^ a b MacArthur, R.; Wilson, E. O. (1967). The Theory of Island Biogeography. Princeton, NJ: Princeton University Press. 
  150. ^ a b Wiens, J. J.; Donoghue, M. J. (2004). "Historical biogeography, ecology and species richness". Trends in Ecology and Evolution 19 (12): 639–644. doi:10.1016/j.tree.2004.09.011. PMID 16701326. 
  151. ^ a b Croizat, L.; Nelson, G.; Rosen, D. E. (1974). "Centers of Origin and Related Concepts". Systematic Zoology 23 (2): 265–287. doi:10.2307/2412139. JSTOR 2412139. 
  152. ^ Wiley, E. O. (1988). "Vicariance Biogeography". Annual Review of Ecology and Systematics 19: 513–542. doi:10.1146/ JSTOR 2097164. 
  153. ^ Morrone, J. J.; Crisci, J. V. (1995). "Historical Biogeography: Introduction to Methods". Annual Review of Ecology and Systematics 26: 373–401. doi:10.1146/ 
  154. ^ Landhäusser, Simon M.; Deshaies, D.; Lieffers, V. J. (2009). "Disturbance facilitates rapid range expansion of aspen into higher elevations of the Rocky Mountains under a warming climate". Journal of Biogeography 37 (1): 68–76. doi:10.1111/j.1365-2699.2009.02182.x. 
  155. ^ Reznick, D.; Bryant, M. J.; Bashey, F. (2002). "r- and K-Selection Revisited: The Role of Population Regulation in Life-History Evolution". Ecology 83 (6): 1509–20. doi:10.1890/0012-9658(2002)083[1509:RAKSRT]2.0.CO;2. ISSN 0012-9658. 
  156. ^ Pianka, E. R. (1972). "r and K Selection or b and d Selection?". The American Naturalist 106 (951): 581–588. doi:10.1086/282798. 
  157. ^ Molecular Ecology
  158. ^ a b Avise, J. (1994). Molecular Markers, Natural History and Evolution. Kluwer Academic Publishers. ISBN 0-412-03771-8. 
  159. ^ O'Brian, E.; Dawson, R. (2007). "Context-dependent genetic benefits of extra-pair mate choice in a socially monogamous passerine". Behav Ecol Sociobiol 61 (5): 775–782. doi:10.1007/s00265-006-0308-8. 
  160. ^ Avise, J. (2000). Phylogeography: The History and Formation of Species. President and Fellows of Harvard College. ISBN 0-674-66638-0. 
  161. ^ a b Young, G.L. (1974). "Human ecology as an interdisciplinary concept: A critical inquiry". Advances in Ecological Research. Advances in Ecological Research 8: 1–105. doi:10.1016/S0065-2504(08)60277-9. ISBN 9780120139088. 
  162. ^ Gross, M. (2004). "Human geography and ecological sociology: The unfolding of human ecology, 1890 to 1930 - and beyond". Social Science History 24 (4): 575–605. doi:10.1215/01455532-28-4-575. 
  163. ^ a b Liu, J. et al. (2009). "Coupled Human and Natural Systems". AMBIO: A Journal of the Human Environment 36 (8): 639–649. doi:10.1579/0044-7447(2007)36[639:CHANS]2.0.CO;2. ISSN 0044-7447. 
  164. ^ Mason, H. L.; Langenheim, J. H. (1957). "Language Analysis and the Concept "Environment"". Ecology 38 (2): 325–340. doi:10.2307/1931693. JSTOR 1931693. 
  165. ^ Kleese, D. A. (2001). "Nature and nature in Psychology". Journal of Theoretical and Philosophical Psy. 21: 61–79. doi:10.1037/h0091199. 
  166. ^ Campbell, Neil A.; Brad Williamson; Robin J. Heyden (2006). Biology: Exploring Life. Boston, Massachusetts: Pearson Prentice Hall. ISBN 0-13-250882-6. 
  167. ^ a b c d e Kormondy, E. (1995). Concepts of ecology. (4th ed.). Benjamin Cummings. ISBN 0134781163. 
  168. ^
  169. ^ Billings, W. D. (1952). "The Environmental Complex in Relation to Plant Growth and Distribution". The Quarterly Review of Biology 27 (3): 251–265. doi:10.1086/399022. JSTOR 2813531. PMID 13004274. 
  170. ^ Singh, J. S. (2006). "Sustainable development of the Indian Himalayan region: Linking ecological and economic concerns" (PDF). Current Science 90 (6): 784–8. 
  171. ^ Marcello, A. (1958). "Climate, plant migration and rhythm". International Journal of Biometeorology 2 (1): 105–107. Bibcode 1958IJBB....2..105M. doi:10.1007/BF02333488. 
  172. ^ a b Hughes, A. R.. "Disturbance and Diversity: An Ecological Chicken and Egg Problem". Nature Education Knowledge 1 (8): 26. 
  173. ^ Levin, S. A. (1992). "The problem of pattern and scale in ecology: the Robert H. MacArthur Award". Ecology 73 (6): 1943–67. doi:10.2307/1941447. JSTOR 1941447. Retrieved 2010-03-16. 
  174. ^ a b Holling, C. S. (1973). "Resilience and Stability of Ecological Systems". Annual Review of Ecology and Systematics 4: 1–23. doi:10.1146/ JSTOR 2096802. 
  175. ^ a b Folke, C.; Carpenter, S.; Walker, B.; Scheffer, M.; Elmqvist, T.; Gunderson, L.; et al., C.S. (2004). "Regime Shifts, Resilience, and Biodiversity in Ecosystem Management". Annual Review of Ecology and Systematics 35: 557–581. doi:10.1146/annurev.ecolsys.35.021103.105711. JSTOR 2096802. 
  176. ^ Morgan Ernst, S. K. et al. (2003). "Thermodynamic and metabolic effects on the scaling of production and population energy use". Ecology Letters 6 (11): 990–5. doi:10.1046/j.1461-0248.2003.00526.x. 
  177. ^ Allègre, Claude J.; Manhès, Gérard; Göpel, Christa (1995). "The age of the Earth". Geochimica et Cosmochimica Acta 59 (8): 1455–1456. Bibcode 1995GeCoA..59.1445A. doi:10.1016/0016-7037(95)00054-4. 
  178. ^ Wills, C.; Bada, J. (2001). The Spark of Life: Darwin and the Primeval Soup. Cambridge, Massachusetts: Perseus Publishing. ISBN 9780738204932. 
  179. ^ a b Goldblatt, C.; Lenton, T. M.; Watson, A. J. (2006). "Bistability of atmospheric oxygen and the Great Oxidation". Nature 443 (7112): 683–6. Bibcode 2006Natur.443..683G. doi:10.1038/nature05169. PMID 17036001. 
  180. ^ Catling, D. C.; Claire, M. W. (2005). "How Earth's atmosphere evolved to an oxic state: A status report". Earth and Planetary Science Letters 237: 1–20. Bibcode 2005E&PSL.237....1C. doi:10.1016/j.epsl.2005.06.013. 
  181. ^ a b c d Cronk, J. K.; Fennessy, M. S. (2001). Wetland Plants: Biology and Ecology. Washington, D.C.: Lewis Publishers. ISBN 1-56670-372-7. 
  182. ^ Evans, D. H.; Piermarini, P. M.; Potts, W. T. W. (1999). "Ionic Transport in the Fish Gill Epithelium". Journal of Experimental Zoology 283 (7): 641–652. doi:10.1002/(SICI)1097-010X(19990601)283:7<641::AID-JEZ3>3.0.CO;2-W. 
  183. ^ Swenson, N. G.; Enquist, B. J. (2008). "The relationship between stem and branch wood specific gravity and the ability of each measure to predict leaf area". American Journal of Botany 95 (4): 516–519. doi:10.3732/ajb.95.4.516. PMID 21632377. 
  184. ^ Gartner, G. E. A. et al. (2010). "Phylogeny, Ecology, and Heart Position in Snakes". Physiological and Biochemical Zoology 83 (1): 43–54. doi:10.1086/648509. PMID 19968564. 
  185. ^ Jacobsen, D. (2008). "Low oxygen pressure as a driving factor for the altitudinal decline in taxon richness of stream macroinvertebrates". Oecologia 154 (4): 795–807. doi:10.1007/s00442-007-0877-x. PMID 17960424. 
  186. ^ Wheeler, T. D.; Stroock, A. D. (2008). "The transpiration of water at negative pressures in a synthetic tree". Nature 455 (7210): 208–212. Bibcode 2008Natur.455..208W. doi:10.1038/nature07226. PMID 18784721. 
  187. ^ Pockman, W. T.; Sperry, J. S.; O'Leary, J. W. (1995). "Sustained and significant negative water pressure in xylem". Nature 378 (6558): 715–716. Bibcode 1995Natur.378..715P. doi:10.1038/378715a0. 
  188. ^ Zimmermann, U.; Schneider, H.; Wegner, L. H.; Wagner, M.; Szimtenings, A.; Haase, F.; Bentrup, FW (2002). "What are the driving forces for water lifting in the xylem conduit?". Physiologia Plantarum 114 (3): 327–335. doi:10.1034/j.1399-3054.2002.1140301.x. PMID 12060254. 
  189. ^ Kastak, D.; Schusterman, R. J. (1998). "Low-frequency amphibious hearing in pinnipeds: Methods, measurements, noise, and ecology". J. Acoust. Soc. Am. 103 (4): 2216–28. Bibcode 1998ASAJ..103.2216K. doi:10.1121/1.421367. PMID 9566340. 
  190. ^ Nishiguchi, Y.; Ito, I.; Okada, M. (2010). "Structure and Function of Lactate Dehydrogenase from Hagfish". Mar Drugs. 8 (3): 594–607. doi:10.3390/md8030594. PMC 2857353. PMID 20411117. 
  191. ^ Friedman, J.; Harder, L. D. (2004). "Inflorescence architecture and wind pollination in six grass species". Functional Ecology 18 (6): 851–860. doi:10.1111/j.0269-8463.2004.00921.x. 
  192. ^ Harder, L. D.; Johnson, S. D. (2009). "Darwin's beautiful contrivances: evolutionary and functional evidence for floral adaptation". New Phytologist 183 (3): 530–545. doi:10.1111/j.1469-8137.2009.02914.x. PMID 19552694. 
  193. ^ Shimeta, J.; Jumars, P. A.; Lessard, E. J. (1995). "Influences of turbulence on suspension feeding by planktonic protozoa; experiments in laminar shear fields". Limnolology and Oceanography 40 (5): 845–859. doi:10.4319/lo.1995.40.5.0845. 
  194. ^ Etemad-Shahidi, A.; Imberger, J. (2001). "Anatomy of turbulence in thermally stratified lakes". Limnolology and Oceanography 46 (5): 1158–70. doi:10.4319/lo.2001.46.5.1158. 
  195. ^ Wolf, B. O.; Walsberg, G. E. (2006). "Thermal Effects of Radiation and Wind on a Small Bird and Implications for Microsite Selection". Ecology 77 (7): 2228–36. doi:10.2307/2265716. JSTOR 2265716. 
  196. ^ Daubenmire, R. (1975). "Floristic plant geography of eastern Washington and northern Idaho". Journal of Biogeography 2 (1): 1–18. doi:10.2307/3038197. JSTOR 3038197. 
  197. ^ Steele, C. A.; Carstens, B. C.; Storfer, A.; Sullivan, J. (2005). "Testing hypotheses of speciation timing in Dicamptodon copei and Dicamptodon aterrimus (Caudata: Dicamptodontidae)". Molecular Phylogenetics and Evolution 36 (1): 90–100. doi:10.1016/j.ympev.2004.12.001. PMID 15904859. 
  198. ^ "Photosynthesis and respiration". Natural Resources Canada. Retrieved 4 February 2010. 
  199. ^ Lenton, T. M.; Watson, A. (2000). "Redfield revisited 2. What regulates the oxygen content of the atmosphere". Global biogeochemical cycles 14 (1): 249–268. Bibcode 2000GBioC..14..249L. doi:10.1029/1999GB900076. 
  200. ^ Lobert, J. M.; Warnatz, J. (1993). Crutzen, P. J.; Goldammer, J. G.. eds. Emissions from the combustion process in vegetation.. Wiley. ISBN 0471936049, 9780471936046. 
  201. ^ Garren, K. H. (1943). "Effects of Fire on Vegetation of the Southeastern United States". Botanical Review 9 (9): 617–654. doi:10.1007/BF02872506. 
  202. ^ Cooper, C. F. (1960). "Changes in Vegetation, Structure, and Growth of Southwestern Pine Forests since White Settlement". Ecological Monographs 30 (2): 130–164. JSTOR 1948549. 
  203. ^ Cooper, C. F. (1961). "The ecology of fire". Scientific American 204 (4): 150–160. doi:10.1038/scientificamerican0461-150. 
  204. ^ van Wagtendonk, Jan W. (2007). "History and Evolution of Wildland Fire Use" (PDF). Fire Ecology Special Issue 3 (2): 3–17. Retrieved 23 April 2011. 
  205. ^ Boerner, R. e. j. (1982). "Fire and Nutrient Cycling in Temperate Ecosystems". BioScience 32 (3): 187–192. doi:10.2307/1308941. JSTOR 1308941. 
  206. ^ Goubitz, S.; Werger, M. J. A.; Ne'eman, G. (2009). "Germination Response to Fire-Related Factors of Seeds from Non-Serotinous and Serotinous Cones". Plant Ecology 169 (2): 195–204. doi:10.1023/A:1026036332277. 
  207. ^ Ne'eman, G.; Goubitz, S.; Nathan, R. (2004). "Reproductive Traits of Pinus halepensis in the Light of Fire: A Critical Review". Plant Ecology 171 (1/2): 69–79. doi:10.1023/B:VEGE.0000029380.04821.99. 
  208. ^ Flematti, Gavin R.; Ghisalberti, Emilio L.; Dixon, Kingsley W.; Trengove, R. D. (2004). "A Compound from Smoke That Promotes Seed Germination" (PDF). Science 305 (5686): 977. doi:10.1126/science.1099944. PMID 15247439. 
  209. ^ Falkowski, P. G.; Fenchel, T.; Delong, E. F. (2008). "The microbial engines that drive Earth's biogeochemical cycles". Science 320 (5879): 1034–9. Bibcode 2008Sci...320.1034F. doi:10.1126/science.1153213. PMID 18497287. 
  210. ^ Grace, J. (2004). "Understanding and managing the global carbon cycle". Journal of Ecology 92 (2): 189–202. doi:10.1111/j.0022-0477.2004.00874.x. 
  211. ^ Pearson, P. N.; Palmer, M. R. (2000). "Atmospheric carbon dioxide concentrations over the past 60 million years". Nature 406 (6797): 695–9. doi:10.1038/35021000. PMID 10963587. 
  212. ^ Pagani, M. et al. (2005). "Marked Decline in Atmospheric Carbon Dioxide Concentrations During the Paleogene". Science 309 (5734): 600–3. Bibcode 2005Sci...309..600P. doi:10.1126/science.1110063. PMID 15961630. 
  213. ^ Cox, P. M. et al. (2000). "Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model". Nature 408 (6809): 184–187. doi:10.1038/35041539. PMID 11089968. 
  214. ^ Heimann, Martin; Reichstein, Markus (2008). "Terrestrial ecosystem carbon dynamics and climate feedbacks". Nature 451 (7176): 289–292. Bibcode 2008Natur.451..289H. doi:10.1038/nature06591. PMID 18202646. 
  215. ^ Davidson, Eric A.; Janssens, Ivan A. (2006). "Temperature sensitivity of soil carbon decomposition and feedbacks to climate change". Nature 440 (7081): 165–173. Bibcode 2006Natur.440..165D. doi:10.1038/nature04514. PMID 16525463. 
  216. ^ Zhuan, Q. et al. (2007). "Net emission of CH4 and CO2 in Alaska: Implications for the region's greenhouse gas budget". Ecological Applications 17 (1): 203–212. doi:10.1890/1051-0761(2007)017[0203:NEOCAC]2.0.CO;2. ISSN 1051-0761. PMID 17479846. 
  217. ^ a b Egerton, F. N. (2001). "A History of the Ecological Sciences: Early Greek Origins" (PDF). Bulletin of the Ecological Society of America 82 (1): 93–7. 
  218. ^ Benson, K. R. (2000). "The emergence of ecology from natural history". Endeavor 24 (2): 59–62. doi:10.1016/S0160-9327(99)01260-0. PMID 10969480. 
  219. ^ Rosenzweig, M.L. (2003). "Reconciliation ecology and the future of species diversity" (PDF). Oryx 37 (2): 194–205. 
  220. ^ Hawkins, B. A. (2001). "Ecology's oldest pattern". Endeavor 25 (3): 133. doi:10.1016/S0160-9327(00)01369-7. 
  221. ^ Kingsland, S. (2004). "Conveying the intellectual challenge of ecology: an historical perspective". Frontiers in Ecology and the Environment 2 (7): 367–374. doi:10.1890/1540-9295(2004)002[0367:CTICOE]2.0.CO;2. ISSN 1540-9295. 
  222. ^ a b McIntosh 1985
  223. ^ a b Stauffer, R. C. (1957). "Haeckel, Darwin and ecology". The Quarterly Review of Biology 32 (2): 138–144. doi:10.1086/401754. 
  224. ^ Friederichs, K. (1958). "A Definition of Ecology and Some Thoughts About Basic Concepts". Ecology 39 (1): 154–159. doi:10.2307/1929981. JSTOR 1929981. 
  225. ^ a b Esbjorn-Hargens, S. (2005). "Integral Ecology: An Ecology of Perspectives" (PDF). Journal of Integral Theory and Practice 1 (1): 2–37. 
  226. ^ Hinchman, L. P.; Hinchman, S. K. (2007). "What we owe the Romantics". Environmental Values 16 (3): 333–354. doi:10.3197/096327107X228382. 
  227. ^ Goodland, R. J. (1975). "The Tropical Origin of Ecology: Eugen Warming's Jubilee". Oikos 26 (2): 240–5. doi:10.2307/3543715. JSTOR 3543715. 
  228. ^ a b Kormandy, E. J.; Wooster, Donald (1978). "Review: Ecology/Economy of Nature—Synonyms?". Ecology 59 (6): 1292–4. doi:10.2307/1938247. JSTOR 1938247. 
  229. ^ Hughes, J. D. (1985). "Theophrastus as Ecologist". Environmental Review 9 (4): 296–306. doi:10.2307/3984460. JSTOR 3984460?. 
  230. ^ Hughes, J. D. (1975). "Ecology in ancient Greece". Inquiry 18 (2): 115–125. doi:10.1080/00201747508601756. 
  231. ^ a b Hector, A.; Hooper, R. (2002). "Darwin and the First Ecological Experiment". Science 295 (5555): 639–640. doi:10.1126/science.1064815. PMID 11809960. 
  232. ^ Sinclair, G. (1826). "On cultivating a collection of grasses in pleasure-grounds or flower-gardens, and on the utility of studying the Gramineae.". London Gardener's Magazine (New-Street-Square: A. & R. Spottiswoode) 1: p. 115. 
  233. ^ Benson, Keith R. (2000). "The emergence of ecology from natural history". Endeavour 24 (2): 59–62. doi:10.1016/S0160-9327(99)01260-0. PMID 10969480. 
  234. ^ Darwin, Charles (1859). On the Origin of Species (1st ed.). London: John Murray. p. 1. ISBN 0801413192. 
  235. ^ Meysman, f. j. r.; Middelburg, Jack J.; Heip, C. H. R. (2006). "Bioturbation: a fresh look at Darwin's last idea". TRENDS in Ecology and Evolution 21 (22): 688–695. doi:10.1016/j.tree.2006.08.002. PMID 16901581. 
  236. ^ Acot, P. (1997). "The Lamarckian Cradle of Scientific Ecology". Acta Biotheoretica 45 (3–4): 185–193. doi:10.1023/A:1000631103244. 
  237. ^ Forbes, S. (1887). "The lake as a microcosm". Bull. of the Scientific Association (Peoria, IL): 77–87. 
  238. ^ May, R. (1999). "Unanswered questions in ecology". Phil. Trans. R. Soc. Lond. B. 354 (1392): 1951–1959. doi:10.1098/rstb.1999.0534. PMC 1692702. PMID 10670015. 
  239. ^ Clements 1905
  240. ^ Simberloff, D. (1980). "A succession of paradigms in ecology: Essentialism to materialism and probalism". Synthese 43: 3–39. doi:10.1007/BF00413854. 
  241. ^ Gleason, H. A. (1926). "The Individualistic Concept of the Plant Association". Bulletin of the Torrey Botanical Club 53 (1): 7–26. doi:10.2307/2479933. JSTOR 2479933. 
  242. ^ Foster, J. B.; Clark, B. (2008). "The Sociology of Ecology: Ecological Organicism Versus Ecosystem Ecology in the Social Construction of Ecological Science, 1926-1935". Organization & Environment 21 (3): 311–352. doi:10.1177/1086026608321632. 
  243. ^ Allee, W. C. (1932). Animal life and social growth. Baltimore: The Williams & Wilkins Company and Associates. 
  244. ^ a b Ghilarov, A. M. (1995). "Vernadsky's Biosphere Concept: An Historical Perspective". The Quarterly Review of Biology 70 (2): 193–203. doi:10.1086/418982. JSTOR 3036242. 
  245. ^ Itô, Y. (1991). "Development of ecology in Japan, with special reference to the role of Kinji Imanishi". Journal of Ecological Research 6 (2): 139–155. doi:10.1007/BF02347158. 

Further reading



External links

Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • Ecology —   Titre abrégé Ecology Discipline Écologie Langue Anglais …   Wikipédia en Français

  • ecology — is the scientific study of the interactions that determine the territorial distribution and abundance of organisms. The term was first used scientifically in 1869 by the German biologist Haekel in a study of plant ecology. Darwin s theory of the… …   Dictionary of sociology

  • ecology — UK US /iːˈkɒlədʒi/ noun [U or C] ► ENVIRONMENT the relationship between living things and their environment: »The developments will extend further into the shore, so further destroying the river s ecology. ► WORKPLACE, COMMERCE the relationship… …   Financial and business terms

  • ecology — ([ e]*k[o^]l [ o]*j[y^]), n. [Gr. o i^kos house + logy.] (Biol.) the branch of biology concerned with the various relations of animals and plants to one another and to their surrounding environment. [PJC] …   The Collaborative International Dictionary of English

  • ecology — has spread rapidly in the 20c from technical to general use to mean ‘the study of the interaction of people with their natural environment’. An earlier spelling oecology, reflecting its origin in the Greek word oikos meaning ‘house’ (the same… …   Modern English usage

  • Ecology — ist ein Journal auf dem Feld der ökologischen Grundlagenforschung und angewandter Ökologie. Es wird herausgegeben von der Ecological Society of America und gehört zu deren Fachjournal Familie. Managing Editor (Schriftleiter) ist J. David Baldwin… …   Deutsch Wikipedia

  • ecology — noun antipollution project, bioecology, bionomics, conservation, environmental science, environmental studies, human environment, maintenance, management of natural resources, natural science, nature study, pollution control, preservation,… …   Law dictionary

  • ecology — 1873, branch of science dealing with the relationship of living things to their environments, coined by German zoologist Ernst Haeckel (1834 1919) as Okologie, from Gk. oikos house, dwelling place, habitation (see VILLA (Cf. villa)) + logia study …   Etymology dictionary

  • ecology — [n] environmental science bionomics, conservation, preservation; concepts 134,257 …   New thesaurus

  • ecology — ► NOUN ▪ the branch of biology concerned with the relations of organisms to one another and to their physical surroundings. DERIVATIVES ecological adjective ecologically adverb ecologist noun. ORIGIN from Greek oikos house …   English terms dictionary

  • ecology — [ē käl′ə jē] n. [Ger ökologie < Gr oikos (see ECO ) + logia, LOGY] 1. a) the branch of biology that deals with the relations between living organisms and their environment b) the complex of relations between a specific organism and its… …   English World dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”