Levels, scope, and scale of organization
The scope of ecology contains a wide array of interacting levels of organization spanning micro-level (e.g., cells) to a planetary scale (e.g.,Hierarchy
The scale of ecological dynamics can operate like a closed system, such as aphids migrating on a single tree, while at the same time remaining open with regard to broader scale influences, such as atmosphere or climate. Hence, ecologists classifyBiodiversity
Biodiversity (an abbreviation of "biological diversity") describes the diversity of life from genes to ecosystems and spans every level of biological organization. The term has several interpretations, and there are many ways to index, measure, characterize, and represent its complex organization. Biodiversity includesHabitat
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. 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." For example, a habitat might be an aquatic or terrestrial environment that can be further categorized as aNiche
Definitions of the niche date back to 1917, but G. Evelyn Hutchinson made conceptual advances in 1957 by introducing a widely adopted definition: "the set of biotic and abiotic conditions in which a species is able to persist and maintain stable population sizes." 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. The Hutchinsonian niche is defined more technically as a " EuclideanNiche construction
Organisms are subject to environmental pressures, but they also modify their habitats. The regulatory feedback between organisms and their environment can affect conditions from local (e.g., a beaverBiome
Biomes are larger units of organization that categorize regions of the Earth's ecosystems, mainly according to the structure and composition of vegetation. There are different methods to define the 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. Biomes includeBiosphere
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 atmosphere's CO2 and O2 composition has been affected by the biogenic flux of gases coming from respiration and photosynthesis, with levels fluctuating over time in relation to the ecology and evolution of plants and animals. Ecological theory has also been used to explain self-emergent regulatory phenomena at the planetary scale: for example, the Gaia hypothesis is an example of holism applied in ecological theory. The Gaia hypothesis states that there is an emergentPopulation ecology
Population ecology studies the dynamics of species populations and how these populations interact with the wider environment. A population consists of individuals of the same species that live, interact, and migrate through the same niche and habitat. A primary law of population ecology is theMetapopulations and migration
The concept of metapopulations was defined in 1969 as "a population of populations which go extinct locally and recolonize". Metapopulation ecology is another statistical approach that is often used in conservation research. Metapopulation models simplify the landscape into patches of varying levels of quality, and 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 a habitat. Migration is also a population-level phenomenon, as with the migration routes followed by plants as they occupied northern post-glacial environments. Plant ecologists use 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 behavior, 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. In metapopulation terminology, migrating individuals are classed as emigrants (when they leave a region) or immigrants (when they enter a region), 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; the population at the site will disappear unless rescued by an adjacent source patch or environmental conditions become more favorable. Metapopulation models examine patch dynamics over time to answer potential 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 are sources when conditions are more favorable. Ecologists use a mixture of computer models and field studies to explain metapopulation structure.Community ecology
Community ecology is the study of the interactions among a collection of species that inhabit the same geographic area. Community ecologists study the determinants of patterns and processes for two or more interacting species. Research in community ecology might measureEcosystem ecology
Ecosystems may be habitats within biomes that form an integrated whole and a dynamically responsive system having both physical and biological complexes. Ecosystem ecology is the science of determining the fluxes of materials (e.g. carbon, phosphorus) between different pools (e.g., tree biomass, soil organic material). Ecosystem ecologists attempt to determine the underlying causes of these fluxes. Research in ecosystem ecology might measureFood webs
A food web is the archetypal ecological network. Plants capture solar energy and use it to synthesize simple sugars during photosynthesis. As plants grow, they accumulate nutrients and are eaten by grazing herbivores, and the energy is transferred through a chain of organisms by consumption. 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 to illustrate and study pathways of energy and material flows. 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, and principles gleaned from food web Microcosm (experimental ecosystem), microcosm studies are extrapolated to larger systems. Feeding relations require extensive investigations into the gut contents of organisms, which can be difficult to decipher, or stable isotopes can be used to trace the flow of nutrient diets and energy through a food web. Despite these limitations, food webs remain a valuable tool in understanding community ecosystems. Food webs exhibit principles of ecological emergence through the nature of trophic relationships: some species have many weak feeding links (e.g., omnivores) while some are more specialized with fewer stronger feeding links (e.g., predator, primary predators). Theoretical and empirical studies identify Random#In biology, non-random emergent patterns of few strong and many weak linkages that explain how ecological communities remain stable over time. Food webs are composed of subgroups where members in a community are linked by strong interactions, and the weak interactions occur between these subgroups. This increases food web stability. Step by step lines or relations are drawn until a web of life is illustrated.Trophic levels
A trophic level (from Greek ''troph'', τροφή, trophē, meaning "food" or "feeding") is "a group of organisms acquiring a considerable majority of its energy from the lower adjacent level (according to ecological pyramids) nearer the abiotic source." Links in food webs primarily connect feeding relations or trophism among species. Biodiversity within ecosystems can be organized into trophic pyramids, in which the vertical dimension represents feeding relations that become further removed from the base of the food chain up toward top predators, and the horizontal dimension represents the Relative species abundance, abundance or biomass at each level. When the relative abundance or biomass of each species is sorted into its respective trophic level, they naturally sort into a 'pyramid of numbers'. Species are broadly categorized as autotrophs (or primary producers), heterotrophs (or consumer (food chain), consumers), and Detritivores (or decomposers). Autotrophs are organisms that produce their own food (production is greater than respiration) by photosynthesis or chemosynthesis. Heterotrophs are organisms that must feed on others for nourishment and energy (respiration exceeds production). Heterotrophs can be further sub-divided into different functional groups, including primary consumers (strict herbivores), Trophic dynamics, secondary consumers (carnivorous predators that feed exclusively on herbivores), and tertiary consumers (predators that feed on a mix of herbivores and predators). 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 compared to herbivores, they are relatively inefficient at grazing. Trophic levels are part of the holistic or complex systems view of ecosystems. Each trophic level contains unrelated species that are grouped together because they share common ecological functions, giving a macroscopic view of the system. 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 led some ecologists to "reiterate that the notion that species clearly aggregate into discrete, homogeneous trophic levels is fiction." 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."Keystone species
A keystone species is a species that is connected to a disproportionately large number of other 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 (termed ''trophic cascades'') that alters trophic dynamics, other food web connections, and can cause the extinction of other species. The term keystone species was coined by Robert Paine in 1969 and is a reference to the Keystone (architecture), keystone architectural feature as the removal of a keystone species can result in a community collapse just as the removal of the keystone in an arch can result in the arch's loss of stability. 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. Hunting of sea otters, for example, is thought to have led indirectly to the extinction of the Steller's sea cow (''Hydrodamalis gigas''). While the keystone species concept has been used extensively as a Conservation biology, conservation tool, it has been criticized for being poorly defined from an operational stance. It is difficult to experimentally determine what species may hold a keystone role in each ecosystem. Furthermore, food web theory suggests that keystone species may not be common, so it is unclear how generally the keystone species model can be applied.Complexity
Complexity is 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. 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." 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'. "Complexity in ecology is of at least six distinct types: spatial, temporal, structural, process, behavioral, and geometric." From these principles, ecologists have identified emergence, emergent and Self-organization#Biology, self-organizing phenomena that operate at different environmental scales of influence, ranging from molecular to planetary, and these require different explanations at each integrative level. Ecological complexity relates to the dynamic resilience of ecosystems that transition to multiple shifting steady-states directed by random fluctuations of history. Long-term ecological studies provide important track records to better understand the complexity and resilience of ecosystems over longer temporal and broader spatial scales. These studies are managed by the International Long Term Ecological Network (LTER). The longest experiment in existence is the Park Grass Experiment, which was initiated in 1856. Another example is the Hubbard Brook Experimental Forest, Hubbard Brook study, which has been in operation since 1960.Holism
Holism remains a critical part of the theoretical foundation in contemporary ecological studies. Holism addresses the Biological organisation, biological organization of life that Systems biology, self-organizes into layers of emergent whole systems that function according to non-reducible properties. This means that higher-order patterns of a whole functional system, such as anRelation to evolution
Ecology and evolutionary biology are considered sister disciplines of the life sciences. Natural selection, life history, Developmental biology, development, adaptation, populations, and heredity, inheritance are examples of concepts that thread equally into ecological and evolutionary theory. Morphological, behavioural, and 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 principles, such as phylogenetics or the Linnaean taxonomy, Linnaean system of taxonomy. The two disciplines often appear together, such as in the title of the journal ''Trends in Ecology and Evolution''. 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. While the boundary between ecology and evolution is not always clear, ecologists study the abiotic and biotic factors that influence evolutionary processes, and evolution can be rapid, occurring on ecological timescales as short as one generation.Behavioural ecology
All organisms can exhibit behaviours. Even plants express complex behaviour, including memory and communication. Behavioural ecology is the study of an organism's behaviour in its environment and its ecological and evolutionary implications. Ethology is the study of observable movement or behaviour in animals. 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. Adaptation is the central unifying concept in behavioural ecology. Behaviours can be recorded as traits and inherited in much the same way that eye and hair colour can. Behaviours can evolve by means of natural selection as adaptive traits conferring functional utilities that increases reproductive fitness. Predator-prey interactions are an introductory concept into food-web studies as well as behavioural ecology. Prey species can exhibit different kinds of behavioural 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 behavioural ecology are generally based on adaptive principles of conservation, optimization, or efficiency. For example, "[t]he threat-sensitive predator avoidance hypothesis predicts that prey should assess the degree of threat posed by different predators and match their behaviour according to current levels of risk" or "[t]he optimal Escape distance, 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." Elaborate sexual display (zoology), displays and posturing are encountered in the behavioural ecology of animals. The birds-of-paradise, for example, sing and display elaborate ornaments during courtship. These displays serve a dual purpose of signalling healthy or well-adapted individuals and desirable genes. The displays are driven by sexual selection as an advertisement of quality of traits among suitors.Cognitive ecology
Cognitive ecology integrates theory and observations from evolutionary ecology and neurobiology, primarily cognitive science, in order to understand the effect that animal interaction with their habitat has on their cognitive systems and how those systems restrict behavior within an ecological and evolutionary framework. "Until recently, however, cognitive scientists have not paid sufficient attention to the fundamental fact that cognitive traits evolved under particular natural settings. With consideration of the selection pressure on cognition, cognitive ecology can contribute intellectual coherence to the multidisciplinary study of cognition." As a study involving the 'coupling' or interactions between organism and environment, cognitive ecology is closely related to enactivism, a field based upon the view that "...we must see the organism and environment as bound together in reciprocal specification and selection...".Social ecology
Social-ecological behaviours are notable in the social insects, slime moulds, social spiders, human society, and naked mole-rats where eusocialism has evolved. Social behaviours include reciprocally beneficial behaviours among kin and nest mates and evolve from kin and group selection. Kin selection explains altruism through genetic relationships, whereby an altruistic behaviour 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 Cloning, clones that share the same genetic make-up as every other male in the colony. 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 behaviours to one another. Groups with predominantly altruistic members survive better than groups with predominantly selfish members.Coevolution
Ecological interactions can be classified broadly into a host (biology), host and an associate relationship. A host is any entity that harbours another that is called the associate. Relationships Interspecific interaction, between species that are mutually or reciprocally beneficial are called mutualisms. Examples of 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. If there is a physical connection between host and associate, the relationship is called symbiosis. Approximately 60% of all plants, for example, have a symbiotic relationship with arbuscular mycorrhizal fungi living in their roots forming an exchange network of carbohydrates for nutrients, mineral nutrients. Indirect mutualisms occur where the organisms live apart. For example, 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 others receive the benefits of clean air at no cost or harm to trees supplying the oxygen. If the associate benefits while the host suffers, the relationship is called parasitism. Although parasites impose a cost to their host (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. Co-evolution is also driven by competition among species or among members of the same species under the banner of reciprocal antagonism, such as grasses competing for growth space. The Red Queen Hypothesis, for example, posits that parasites track down and specialize on the locally common genetic defense systems of its host that drives the evolution of sexual reproduction to diversify the genetic constituency of populations responding to the antagonistic pressure.Biogeography
Biogeography (an amalgamation of ''biology'' and ''geography'') is the comparative study of the geographic distribution of organisms and the corresponding evolution of their traits in space and time. The ''Journal of Biogeography'' was established in 1974. Biogeography and ecology share many of their disciplinary roots. For example, Island biogeography, the theory of island biogeography, published by the Robert MacArthur and Edward O. Wilson in 1967 is considered one of the fundamentals of ecological theory. Biogeography has a long history in the natural sciences concerning the spatial distribution of plants and animals. Ecology and evolution provide the explanatory context for biogeographical studies. Biogeographical patterns result from ecological processes that influence range distributions, such asr/K selection theory
A population ecology concept is r/K selection theory, one of the first predictive models in ecology used to explain Life history theory, life-history evolution. The premise behind the r/K selection model is that natural selection pressures change according to population densities, 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 availableMolecular 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, polymerase chain reaction (PCR). The rise of molecular technologies and the influx of research questions into this new ecological field resulted in the publication ''Molecular Ecology'' in 1992. 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''. 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 behavioural and biogeographical ecology. For example, molecular ecology revealed promiscuous sexual behaviour and multiple male partners in tree swallows previously thought to be socially monogamous. In a biogeographical context, the marriage between genetics, ecology, and evolution resulted in a new sub-discipline called phylogeography.Human ecology
Ecology is as much a biological science as it is a human science. Human ecology is an interdisciplinary investigation into the ecology of our species. "Human ecology may be defined: (1) from a bioecological standpoint as the study of man as the ecological dominant in plant and animal communities and systems; (2) from a bioecological 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." The term 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. The ecological complexities human beings are facing through the technological transformation of the planetary biome has brought on the Anthropocene. The unique set of circumstances has generated the need for a new unifying science called coupled human and natural systems that builds upon, but moves beyond the field of human ecology. Ecosystems tie into human societies through the critical and all-encompassing life-supporting functions they sustain. In recognition of these functions and the incapability of traditional economic valuation methods to see the value in ecosystems, there has been a surge of interest in social capital, social-natural capital, which provides the means to put a value on the stock and use of information and materials stemming from ecosystem services, ecosystem goods and services. Ecosystems produce, regulate, maintain, and supply services of critical necessity and beneficial to human health (cognitive and physiological), economies, and they even provide an information or reference function as a living library giving opportunities for science and cognitive development in children engaged in the complexity of the natural world. Ecosystems relate importantly to human ecology as they are the ultimate base foundation of global economics as every commodity, and the capacity for exchange ultimately stems from the ecosystems on Earth. Ecology is an employed science of restoration, repairing disturbed sites through human intervention, in natural resource management, and in environmental impact assessments. Edward O. Wilson predicted in 1992 that the 21st century "will be the era of restoration in ecology". Ecological science has boomed in the industrial investment of restoring ecosystems and their processes in abandoned sites after disturbance. Natural resource managers, in silviculture, forestry, for example, employ ecologists to develop, adapt, and implement Ecosystem management, ecosystem based methods into the planning, operation, and restoration phases of land-use. Another example of conservation is seen on the east coast of the United States in Boston, MA. The city of Boston implemented the Wetland Ordinance, improving the stability of their wetland environments by implementing soil amendments that will improve groundwater storage and flow, and trimming or removal of vegetation that could cause harm to water quality. Ecological science is used in the methods of sustainable harvesting, disease, and fire outbreak management, in fisheries stock management, for integrating land-use with protected areas and communities, and conservation in complex geo-political landscapes.Relation to the environment
The environment of ecosystems includes both physical parameters and biotic attributes. It is dynamically interlinked and containsDisturbance and resilience
Ecosystems are regularly confronted with natural environmental variations and disturbances over time and geographic space. A disturbance is any process that removes biomass from a community, such as a fire, flood, drought, or predation. Disturbances occur over vastly different ranges in terms of magnitudes as well as distances and time periods, and are both the 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 from the patchwork of natural experimentation and opportunity. Ecological resilience is a cornerstone theory in ecosystem management. Biodiversity fuels the resilience of ecosystems acting as a kind of regenerative insurance.Metabolism and the early atmosphere
The Earth was formed approximately 4.5 billion years ago. As it cooled and a crust and oceans formed, its 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 into a mixture 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 Redox, reducing and oxidizing gasses that set the stage for primitive ecosystems to evolve and, in turn, the atmosphere also evolved. 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. 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 reduced hydrogen concentrations and increased atmospheric methane, by converting hydrogen sulfide into water or other sulfur compounds (for example, 2H2S + CO2 + h''v'' → CH2O + H2O + 2S). Early forms of Fermentation (biochemistry), fermentation also increased levels of atmospheric methane. The transition to an oxygen-dominant atmosphere (the ''Great Oxygenation Event, 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.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, behaviour, andPhysical environments
Water
Diffusion of carbon dioxide and oxygen is approximately 10,000 times slower in water than in air. When soils are flooded, they quickly lose oxygen, becoming Hypoxia (environmental), hypoxic (an environment with O2 concentration below 2 mg/liter) and eventually completely Anoxic waters, anoxic where anaerobic bacteria thrive among the roots. Water also influences the intensity and Electromagnetic spectrum, spectral composition of light as it reflects off the water surface and submerged particles. Aquatic plants exhibit a wide variety of morphological and physiological adaptations that allow them to survive, compete, and diversify in these environments. For example, their roots and stems contain large air spaces (aerenchyma) that regulate the efficient transportation of gases (for example, CO2 and O2) used in respiration and photosynthesis. Salt water plants (halophytes) have additional specialized adaptations, such as the development of special organs for shedding salt and osmoregulation, osmoregulating their internal salt (NaCl) concentrations, to live in Estuary, estuarine, brackish, or oceanic environments. Anaerobic soil microorganisms in aquatic environments use nitrate, Manganese, manganese ions, ferric, ferric ions, sulfate, carbon dioxide, and some organic compounds; other microorganisms are facultative anaerobes and use oxygen during respiration when the soil becomes drier. The activity of soil microorganisms and the chemistry of the water reduces the Reduction potential, oxidation-reduction potentials of the water. Carbon dioxide, for example, is reduced to methane (CH4) by methanogenic bacteria. The physiology of fish is also specially adapted to compensate for environmental salt levels through osmoregulation. Their gills form electrochemical gradients that mediate salt excretion in salt water and uptake in fresh water.Gravity
The shape and energy of the land are significantly affected by gravitational forces. On a large scale, the distribution of gravitational forces on the earth is uneven and influences the shape and movement of tectonic plates as well as influencing geomorphic processes such as orogeny andPressure
Climatic and osmotic pressure places physiological constraints on organisms, especially those that fly and respire at high altitudes, or dive 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. For example, oxygen levels decrease with decreasing pressure and are a limiting factor for life at higher altitudes. Xylem, Water transportation by plants is another important ecophysiology, ecophysiological process affected by osmotic pressure gradients. Fluid pressure, Water pressure in the depths of oceans requires that organisms adapt to these conditions. For example, diving animals such as whales, dolphins, and seal (animal), seals are specially adapted to deal with changes in sound due to water pressure differences. Differences between hagfish species provide another example of adaptation to deep-sea pressure through specialized protein adaptations.Wind and turbulence
Turbulent forces in air and water affect 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. 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, affecting how fish, algae, and other parts of the aquatic ecosystem are structured. Wind speed and turbulence also influence evapotranspiration rates and energy budgets in plants and animals. Wind speed, temperature and moisture content can vary as winds travel across different land features and elevations. For example, the westerlies 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 increase in elevation; this is called orographic lift and can cause precipitation. 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 (e.g., of the Columbia River Drainage Basin, Columbia Basin in western North America) to intermix with sister lineages that are segregated to the interior mountain systems.Fire
Plants convert carbon dioxide into biomass and emit oxygen into the atmosphere. By approximately 350 million years ago (the end of the Devonian period), photosynthesis had brought the concentration of atmospheric oxygen above 17%, which allowed combustion to occur. 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. While the issue of fire in relation to ecology and plants has been recognized for a long time, Charles F. Cooper (ecologist), Charles Cooper brought attention to the issue of forest fires in relation to the ecology of forest fire suppression and management in the 1960s. Indigenous peoples of the Americas, 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. Fire creates a heterogeneous ecosystem age and canopy structure, and the altered soil nutrient supply and cleared canopy structure opens new ecological niches for seedling establishment. Most ecosystems 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 germination, germinate until after their seeds have lived through a fire or been exposed to certain compounds from smoke. Environmentally triggered germination of seeds is called serotiny. Fire plays a major role in the persistence and Resilience (ecology), resilience of ecosystems.Soils
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 (for example, leaves on the forest floor), results in soils containing minerals and nutrients that feed into plant production. The whole of the planet's soil ecosystems is called the pedosphere where a large biomass of the Earth's biodiversity organizes into trophic levels. Invertebrates that feed and shred larger leaves, for example, create smaller bits for smaller organisms in the feeding chain. Collectively, these organisms are the detritivores that regulate soil formation. 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. Soils form composite phenotypes where inorganic matter is enveloped into the physiology of a whole community. As organisms feed and migrate through soils they physically displace materials, an ecological process called bioturbation. This aerates soils and stimulates heterotrophic growth and production. Soil microorganisms are influenced by and are fed back into the trophic dynamics of the ecosystem. No single axis of causality can be discerned to segregate the biological from geomorphological systems in soils. Paleoecology, Paleoecological studies of soils places the origin for bioturbation to a time before the Cambrian period. Other events, such as the Tree#Evolutionary history, evolution of trees and the Evolutionary history of life#Colonization of land, colonization of land in the Devonian period played a significant role in the early development of ecological trophism in soils.Biogeochemistry and climate
Ecologists study and measure nutrient budgets to understand how these materials are regulated, flow, and recycling (ecological), recycled through the environment. This research has led to an understanding that there is global feedback between ecosystems and the physical parameters of this planet, including minerals, soil, pH, ions, water, and atmospheric gases. Six major elements (hydrogen, carbon, nitrogen, oxygen, sulfur, and phosphorus; H, C, N, O, S, and P) 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. The ecology of global carbon budgets gives one example of the linkage between biodiversity and biogeochemistry. It is estimated that the Earth's oceans hold 40,000 gigatonnes (Gt) of carbon, that vegetation and soil hold 2070 Gt, and that fossil fuel emissions are 6.3 Gt carbon per year. There have been major restructurings in these global carbon budgets during the Earth's history, 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 Parts per million, ppm. In the Oligocene, from twenty-five to thirty-two million years ago, there was another significant restructuring of the global carbon cycle as grasses evolved a new mechanism of photosynthesis, C4 carbon fixation, C4 photosynthesis, and expanded their ranges. This new pathway evolved in response to the drop in atmospheric CO2 concentrations below 550 ppm. The relative abundance and distribution of biodiversity alters the dynamics between organisms and their environment such that ecosystems can be both cause and effect in relation to climate change. Human-driven modifications to the planet's ecosystems (e.g., disturbance, biodiversity loss, agriculture) contributes to rising atmospheric greenhouse gas levels. Transformation of the global carbon cycle in the next century is projected to raise planetary temperatures, lead to more extreme fluctuations in weather, alter species distributions, and increase extinction rates. The effect of global warming is already being registered in melting glaciers, melting mountain ice caps, and rising sea levels. Consequently, species distributions are changing along waterfronts and in continental areas where migration patterns and breeding grounds are tracking the prevailing shifts in climate. Large sections of permafrost are also melting to create a new mosaic of flooded areas having increased rates of soil decomposition activity that raises methane (CH4) emissions. There is concern over increases in atmospheric methane in the context of the global carbon cycle, because methane is a greenhouse gas that is 23 times more effective at absorbing long-wave radiation than CO2 on a 100-year time scale. Hence, there is a relationship between global warming, decomposition and respiration in soils and wetlands producing significant climate feedbacks and globally altered biogeochemical cycles.History
Early beginnings
Ecology has a complex origin, due in large part to its interdisciplinary nature. Ancient Greek philosophers such as Hippocrates and Aristotle were among the first to record observations on natural history. However, they viewed life in terms of essentialism, where species were conceptualized as static unchanging things while varieties were seen as aberrations of an Idealism, idealized type. This contrasts against the modern understanding of Theoretical ecology, ecological theory where varieties are viewed as the real phenomena of interest and having a role in the origins of adaptations by means ofSince 1900
Modern ecology is a young science that first attracted substantial scientific attention toward the end of the 19th century (around the same time that evolutionary studies were gaining scientific interest). The scientist Ellen Swallow Richards adopted the term "oekology" (which eventually morphed into home economics) in the U.S. as early as 1892. In the early 20th century, ecology transitioned from a more metaphysics, descriptive form of natural history to a more scientific method, analytical form of ''scientific natural history''. Frederic Clements published the first American ecology book in 1905, presenting the idea of plant communities as a superorganism. This publication launched a debate between ecological holism and individualism that lasted until the 1970s. Clements' superorganism concept proposed that ecosystems progress through regular and determined stages of seral development that are analogous to the developmental stages of an organism. The Clementsian paradigm was challenged by Henry Gleason, who stated that 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. The Clementsian superorganism theory was an overextended application of an idealism, idealistic form of holism. The term "holism" was coined in 1926 by Jan Smuts, Jan Christiaan Smuts, a South African general and polarizing historical figure who was inspired by Clements' superorganism concept. Around the same time, Charles Sutherland Elton, Charles Elton pioneered the concept of food chains in his classical book ''Animal Ecology''. Elton defined ecological relations using concepts of food chains, food cycles, and 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. Alfred J. Lotka brought in many theoretical concepts applying thermodynamic principles to ecology. In 1942, Raymond Lindeman wrote a landmark paper on the Trophic dynamics#Trophic dynamics, trophic dynamics of ecology, which was published posthumously after initially being rejected for its theoretical emphasis. Trophic dynamics became the foundation for much of the work to follow on energy and material flow through ecosystems. Robert MacArthur advanced mathematical theory, predictions, and tests in ecology in the 1950s, which inspired a resurgent school of theoretical mathematical ecologists. Ecology also has developed through contributions from other nations, including Russia's Vladimir Vernadsky and his founding of the biosphere concept in the 1920s and Japan's Kinji Imanishi and his concepts of harmony in nature and habitat segregation in the 1950s. Scientific recognition of contributions to ecology from non-English-speaking cultures is hampered by language and translation barriers. Ecology surged in popular and scientific interest during the 1960–1970s environmental movement. There are strong historical and scientific ties between ecology, environmental management, and protection. The historical emphasis and poetic naturalistic writings advocating the protection of wild places by notable ecologists in the history of conservation biology, such as Aldo Leopold and Arthur Tansley, have been seen as far removed from urban centres where, it is claimed, the concentration of pollution and environmental degradation is located. Palamar (2008) notes an overshadowing by mainstream environmentalism of pioneering women in the early 1900s who fought for urban health ecology (then called euthenics) and brought about changes in environmental legislation. Women such as Ellen Swallow Richards and Julia Lathrop, among others, were precursors to the more popularized environmental movements after the 1950s. In 1962, marine biologist and ecologist Rachel Carson's book ''Silent Spring'' helped to mobilize the environmental movement by alerting the public to toxic pesticides, such as DDT, Bioaccumulation, bioaccumulating in the environment. Carson used ecological science to link the release of environmental toxins to human and ecosystem health. Since then, ecologists have worked to bridge their understanding of the degradation of the planet's ecosystems with environmental politics, law, restoration, and natural resources management.See also
* Carrying capacity * Chemical ecology * Climate justice * Circles of Sustainability * Cultural ecology * Dialectical naturalism * Ecological death * Ecological psychology * Ecology movement * Ecosophy * Ecopsychology * Human ecology * Industrial ecology * Information ecology * Landscape ecology * Natural resource * Normative science * Philosophy of ecology * Political ecology * Theoretical ecology * Sensory ecology * Sexecology * Spiritual ecology * Sustainable development ; Lists * Glossary of ecology * Index of biology articles * List of ecologists * Outline of biology * :Ecology terminology, Terminology of ecologyNotes
, meaning "dwelling place, distributional area" —quoted from Stauffer (1957).References
{{Reflist, 30em, refs= {{Cite journal , last=Acot , first=P. , title=The Lamarckian cradle of scientific ecology , journal=Acta Biotheoretica , volume=45 , issue=3–4 , pages=185–193 , year=1997 , doi=10.1023/A:1000631103244, s2cid=83288244 {{Cite journal , last=Aguirre , first=A. A. , title=Biodiversity and human health , journal=EcoHealth , year=2009 , doi=10.1007/s10393-009-0242-0 , volume=6 , pages=153–156, s2cid=27553272 {{Cite book , last=Allee , first=W. C. , title=Animal Life and Social Growth , publisher=The Williams & Wilkins Company and Associates , location=Baltimore , year=1932 {{Cite book , last1=Allee , first1=W. C. , last2=Park , first2=O. , last3=Emerson , first3=A. E. , last4=Park , first4=T. , last5=Schmidt , first5=K. P. , title=Principles of Animal Ecology , publisher=W. B. Sunders, Co. , year=1949 , page=837 , url=https://archive.org/stream/principlesofanim00alle#page/n5/mode/2up , isbn=0-7216-1120-6 {{Cite journal , last1=Allègre , first1=Claude J. , last2=Manhès , first2=Gérard , last3=Göpel , first3=Christa , title=The age of the Earth , journal=Geochimica et Cosmochimica Acta , volume=59 , issue=8 , year=1995 , pages=1455–1456 , doi=10.1016/0016-7037(95)00054-4, bibcode=1995GeCoA..59.1445A {{Cite journal , last=Anderson , first=J. D. , title=The courtship behaviour of ''Ambystoma macrodactylum croceum'' , journal=Copeia , volume=1961 , pages=132–139 , year=1961 , issue=2, jstor=1439987 , doi = 10.2307/1439987 {{Cite journal , last=Anderson, first=P. K. , title=Competition, predation, and the evolution and extinction of Steller's sea cow, ''Hydrodamalis gigas'' , year=1995 , journal=Marine Mammal Science , volume=11 , issue=3 , pages=391–394 , doi=10.1111/j.1748-7692.1995.tb00294.x {{Cite book , last=Avise , first=J. , title=Molecular Markers, Natural History and Evolution , publisher=Kluwer Academic Publishers , year=1994 , url=https://books.google.com/books?id=2zYnQfnXNr8C , isbn=0-412-03771-8 , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318151507/http://books.google.com/books?id=2zYnQfnXNr8C , url-status=live {{Cite book , last=Avise , first=J. , title=Phylogeography: The History and Formation of Species , publisher=President and Fellows of Harvard College , year=2000 , url=https://books.google.com/books?id=lA7YWH4M8FUC , isbn=0-674-66638-0 , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318143956/http://books.google.com/books?id=lA7YWH4M8FUC , url-status=live {{Cite book , last1=Begon , first1=M. , last2=Townsend , first2=C. R. , last3=Harper , first3=J. L. , title=Ecology: From Individuals to Ecosystems , year=2005 , edition=4th , publisher=Wiley-Blackwell , page=752 , isbn=1-4051-1117-8 , url=http://ca.wiley.com/WileyCDA/WileyTitle/productCd-1405111178.html , url-status=dead , archive-url=https://web.archive.org/web/20131030083242/http://ca.wiley.com/WileyCDA/WileyTitle/productCd-1405111178.html , archive-date=30 October 2013 , access-date=14 December 2010 {{Cite journal , last=Benson , first=Keith R. , title=The emergence of ecology from natural history , journal=Endeavour , volume=24 , issue=2 , pages=59–62 , year=2000 , doi=10.1016/S0160-9327(99)01260-0 , pmid=10969480 {{Cite journal , last=Berryman , first=A. A. , s2cid=84321947 , title=The origins and evolution of predator-prey theory , journal=Ecology , volume=73 , issue=5 , pages=1530–1535 , year=1992 , doi=10.2307/1940005, jstor=1940005 {{Cite journal , last1=Beyer , first1=Hawthorne, L. , last2=Haydon , first2=Daniel, T. , last3=Morales , first3=Juan M. , last4=Frair , first4=Jacqueline L. , last5=Hebblewhite , first5=Mark , last6=Mitchell , first6=Michael , last7=Matthiopoulos , first7=Jason , title=The interpretation of habitat preference metrics under use–availability designs , journal=Philosophical Transactions of the Royal Society B , volume=365 , issue=1550 , pages=2245–2254 , year=2010 , pmid=20566501 , pmc=2894962 , doi=10.1098/rstb.2010.0083 {{Cite journal , last=Boerner , first=R. E. J. , title=Fire and nutrient cycling in temperate ecosystems , journal=BioScience , volume=32 , issue=3 , pages=187–192 , year=1982 , doi=10.2307/1308941, jstor=1308941 {{Cite journal , last1=Boucher , first1=D. H. , last2=James , first2=S. , last3=Keeler , first3=K. H. , s2cid=33027458 , title=The ecology of mutualism , journal=Annual Review of Ecology and Systematics , volume=13 , pages=315–347 , year=1982 , doi=10.1146/annurev.es.13.110182.001531 {{cite journal , last1=Bronstein , first1= J. L. , year=2018 , title=The exploitation of mutualisms , journal=Ecology Letters , volume=4 , pages=277–287 , doi=10.1046/j.1461-0248.2001.00218.x, issue=3 {{Cite book , last1=Campbell , first1=Neil A. , last2=Williamson , first2=Brad , last3=Heyden , first3=Robin J. , title=Biology: Exploring Life , publisher=Pearson Prentice Hall , year=2006 , location=Boston, Massachusetts , url=http://www.phschool.com/el_marketing.html , isbn=0-13-250882-6 , url-status=live , archive-url=https://web.archive.org/web/20141102041816/http://www.phschool.com/el_marketing.html , archive-date=2 November 2014 {{Cite journal , last1=Scheffer , first1=M. , last2=Carpenter , first2=S. , last3=Foley , first3=J. A. , last4=Walker , first4=B. , last5=Walker , first5=B. , title=Catastrophic shifts in ecosystems , journal=Nature , volume=413 , issue=6856 , pages=591–596 , url=http://bio.classes.ucsc.edu/bioe107/Scheffer%202001%20Nature.pdf , doi=10.1038/35098000 , pmid=11595939 , year=2001 , bibcode=2001Natur.413..591S , s2cid=8001853 , url-status=dead , archive-url=https://web.archive.org/web/20110720075303/http://bio.classes.ucsc.edu/bioe107/Scheffer%202001%20Nature.pdf , archive-date=20 July 2011 , access-date=4 June 2011 {{Cite journal , last1=Catling , first1=D. C. , last2=Claire , first2=M. W. , title=How Earth's atmosphere evolved to an oxic state: A status report , journal=Earth and Planetary Science Letters , volume=237 , issue=1–2 , year=2005 , pages=1–20 , url=http://www.atmos.washington.edu/~davidc/papers_mine/Catling2005-EPSL.pdf , doi=10.1016/j.epsl.2005.06.013 , bibcode=2005E&PSL.237....1C , url-status=dead , archive-url=https://web.archive.org/web/20081010145128/http://www.atmos.washington.edu/~davidc/papers_mine/Catling2005-EPSL.pdf , archive-date=10 October 2008 , access-date=6 September 2009 {{Cite journal, last1=Ceballos , first1=G. , last2=Ehrlich , first2=P. R. , title=Mammal population losses and the extinction crisis , journal=Science , volume=296 , issue=5569 , pages=904–907 , year=2002 , url=http://epswww.unm.edu/facstaff/gmeyer/envsc330/CeballosEhrlichmammalextinct2002.pdf , access-date=16 March 2010 , doi=10.1126/science.1069349 , pmid=11988573 , bibcode=2002Sci...296..904C , s2cid=32115412 , url-status=dead , archive-url=https://web.archive.org/web/20110720094351/http://epswww.unm.edu/facstaff/gmeyer/envsc330/CeballosEhrlichmammalextinct2002.pdf , archive-date=20 July 2011 {{Cite journal , last1=Clark , first1=J. S. , last2=Fastie , first2=C. , last3=Hurtt , first3=G. , last4=Jackson , first4=S. T. , last5=Johnson , first5=C. , last6=King , first6=G. A. , last7=Lewis , first7=M. , last8=Lynch , first8=J. , last9=Pacala , first9=S. , last10=Prentice , first10=Colin , last11=Schupp , first11=Eugene W. , last12=Webb , first12=Thompson , last13=Wyckoff , first13=Peter , title=Reid's paradox of rapid plant migration , journal=BioScience , volume=48 , issue=1 , year=1998 , pages=13–24 , url=http://www.mathstat.ualberta.ca/~mlewis/publications/25Clark1998B.pdf , doi=10.2307/1313224 , display-authors=9 , jstor=1313224 , url-status=live , archive-url=https://web.archive.org/web/20110706210036/http://www.mathstat.ualberta.ca/~mlewis/publications/25Clark1998B.pdf , archive-date=6 July 2011, doi-access=free {{Cite book , last1=Coleman , first1=D. C. , last2=Corssley , first2=D. A. , last3=Hendrix , first3=P. F. , title=Fundamentals of Soil Ecology , publisher=Academic Press , year=2004 , edition=2nd , isbn=0-12-179726-0 , url=https://books.google.com/books?id=pKKDJwu_OlkC , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318165456/http://books.google.com/books?id=pKKDJwu_OlkC , url-status=live {{Cite journal , last=Cooper , first=C. F. , title=Changes in vegetation, structure, and growth of southwestern pine forests since white settlement , journal=Ecological Monographs , volume=30 , issue=2 , pages=130–164 , year=1960, doi = 10.2307/1948549 , jstor=1948549 {{Cite journal , last=Cooper , first=C. F. , title=The ecology of fire , journal=Scientific American , volume=204 , issue=4 , pages=150–160 , year=1961 , doi=10.1038/scientificamerican0461-150 , bibcode=1961SciAm.204d.150C {{Cite journal , last1=Cooper , first1=W. E. , last2=Frederick , first2=W. G. , title=Predator lethality, optimal escape behavior, and autotomy , journal=Behavioral Ecology , volume=21 , issue=1 , pages=91–96 , year=2010 , doi=10.1093/beheco/arp151, doi-access=free {{Cite journal, last1=Cox , first1=Peter M. , last2=Betts , first2=Richard A. , last3=Jones , first3=Chris D. , last4=Spall , first4=Steven A. , last5=Totterdell , first5=Ian J. , title=Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model , journal=Nature , volume=408 , pages=184–187 , year=2000 , url=http://quercus.igpp.ucla.edu/teaching/papers_to_read/cox_etal_nat_00.pdf , doi=10.1038/35041539 , pmid=11089968 , issue=6809 , url-status=dead , archive-url=https://web.archive.org/web/20120917004108/http://quercus.igpp.ucla.edu/teaching/papers_to_read/cox_etal_nat_00.pdf , archive-date=17 September 2012 , bibcode=2000Natur.408..184C, s2cid=2689847 {{Cite book , last1=Cronk , first1=J. K. , last2=Fennessy , first2=M. S. , title=Wetland Plants: Biology and Ecology , location=Washington, D.C. , publisher=Lewis Publishers , year=2001 , url=https://books.google.com/books?id=FNI1GFbH2eQC , isbn=1-56670-372-7 , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318183910/http://books.google.com/books?id=FNI1GFbH2eQC , url-status=live {{Cite book , last=Darwin , first=Charles , author-link=Charles Darwin , year=1859 , title=On the Origin of Species , location=London, UK , publisher=John Murray , edition=1st , page=1 , url=http://darwin-online.org.uk/content/frameset?itemID=F373&viewtype=text&pageseq=16 , isbn=0-8014-1319-2 , url-status=live , archive-url=https://web.archive.org/web/20070713123034/http://darwin-online.org.uk/content/frameset?itemID=F373&viewtype=text&pageseq=16 , archive-date=13 July 2007 {{Cite journal , last=Daubenmire , first=R. , title=Floristic plant geography of eastern Washington and northern Idaho , journal=Journal of Biogeography , volume=2 , issue=1 , pages=1–18 , year=1975 , doi=10.2307/3038197, jstor=3038197 {{Cite journal , last1=Davic , first1=R. D. , last2=Welsh , first2=H. H. , title=On the ecological role of salamanders , journal=Annual Review of Ecology and Systematics , volume=35 , pages=405–434 , year=2004 , url=http://www.fs.fed.us/psw/publications/welsh/captured/psw_2004_welsh008.pdf , doi=10.1146/annurev.ecolsys.35.112202.130116 , url-status=live , archive-url=https://web.archive.org/web/20090824103331/http://www.fs.fed.us/psw/publications/welsh/captured/psw_2004_welsh008.pdf , archive-date=24 August 2009 {{Cite journal , last=Davic , first=R. D. , title=Linking keystone species and functional groups: a new operational definition of the keystone species concept , journal=Conservation Ecology , volume=7 , issue=1 , pages=r11 , year=2003 , doi=10.5751/ES-00502-0701r11 , hdl=10535/2966 , url=http://dlc.dlib.indiana.edu/dlc/bitstream/handle/10535/2966/linking.pdf?sequence=1&isAllowed=y , access-date=24 September 2019 , archive-date=30 July 2020 , archive-url=https://web.archive.org/web/20200730215632/http://dlc.dlib.indiana.edu/dlc/bitstream/handle/10535/2966/linking.pdf?sequence=1&isAllowed=y , url-status=live , hdl-access=free {{Cite journal , last1=Davidson , first1=Eric A. , last2=Janssens , first2=Ivan A. , title=Temperature sensitivity of soil carbon decomposition and feedbacks to climate change , journal=Nature , volume=440 , pages=165–173 , year=2006 , doi=10.1038/nature04514 , pmid=16525463 , issue=7081, bibcode=2006Natur.440..165D, doi-access=free {{Cite journal , last1=de Groot , first1=R. S. , last2=Wilson , first2=M. A. , last3=Boumans , first3=R. M. J. , title=A typology for the classification, description and valuation of ecosystem functions, goods and services , journal=Ecological Economics , volume=41 , issue=3 , pages=393–408 , year=2002 , url=http://yosemite.epa.gov/SAB/sabcvpess.nsf/e1853c0b6014d36585256dbf005c5b71/1c7c986c372fa8d485256e29004c7084/$FILE/deGroot%20et%20al.pdf , doi=10.1016/S0921-8009(02)00089-7 , url-status=live , archive-url=https://web.archive.org/web/20110609075252/http://yosemite.epa.gov/SAB/sabcvpess.nsf/e1853c0b6014d36585256dbf005c5b71/1c7c986c372fa8d485256e29004c7084/$FILE/deGroot%20et%20al.pdf , archive-date=9 June 2011 {{Cite journal , last=DeLong , first=E. F. , title=The microbial ocean from genomes to biomes , journal=Nature , volume=459 , pages=200–206 , year=2009 , url=http://researchpages.net/media/resources/2009/07/30/nature08059.pdf , doi=10.1038/nature08059 , pmid=19444206 , issue=7244 , bibcode=2009Natur.459..200D , url-status=dead , archive-url=https://web.archive.org/web/20110718062251/http://researchpages.net/media/resources/2009/07/30/nature08059.pdf , archive-date=18 July 2011 , hdl=1721.1/69838 , s2cid=205216984 , access-date=14 January 2010 , hdl-access=free {{Cite book , last=Dingle , first=H. , title=Migration: The Biology of Life on the Move , publisher=Oxford University Press , isbn=0-19-509723-8 , page=480 , url=https://books.google.com/books?id=adguyA_ZlAMC , date=18 January 1996 , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318130627/http://books.google.com/books?id=adguyA_ZlAMC , url-status=live {{Cite journal , last1=Duffy , first1=J. Emmett , last2=Cardinale , first2=Bradley J. , last3=France , first3=Kristin E. , last4=McIntyre , first4=Peter B. , last5=Thébault , first5=Elisa , last6=Loreau , first6=Michel , title=The functional role of biodiversity in ecosystems: incorporating trophic complexity , journal=Ecology Letters , volume=10 , issue=6 , pages=522–538 , year=2007 , doi=10.1111/j.1461-0248.2007.01037.x , pmid=17498151 , url=https://scholarworks.wm.edu/cgi/viewcontent.cgi?article=1655&context=vimsarticles , access-date=7 December 2019 , archive-date=5 March 2020 , archive-url=https://web.archive.org/web/20200305121833/https://scholarworks.wm.edu/cgi/viewcontent.cgi?article=1655&context=vimsarticles , url-status=live , doi-access=free {{Cite journal, last=Eastwood , first=R. , title=Successive replacement of tending ant species at aggregations of scale insects (Hemiptera: Margarodidae and Eriococcidae) on ''Eucalyptus'' in south-east Queensland , journal=Australian Journal of Entomology , volume=43 , pages=1–4 , year=2004 , url=http://www.oeb.harvard.edu/faculty/pierce/people/eastwood/resources/pdfs/Scale-ant2004.pdf , doi=10.1111/j.1440-6055.2003.00371.x , url-status=dead , archive-url=https://web.archive.org/web/20110917171800/http://www.oeb.harvard.edu/faculty/pierce/people/eastwood/resources/pdfs/Scale-ant2004.pdf , archive-date=17 September 2011 {{Cite journal , last1=Edwards , first1=J. , last2=Fraser , first2=K. , title=Concept maps as reflectors of conceptual understanding , journal=Research in Science Education , volume=13 , issue=1 , pages=19–26 , year=1983 , doi=10.1007/BF02356689, bibcode=1983RScEd..13...19E, s2cid=144922522 {{Cite journal , last=Egerton , first=F. N. , title=A history of the ecological sciences: early Greek origins , journal=Bulletin of the Ecological Society of America , volume=82 , issue=1 , pages=93–97 , year=2001 , url=http://esapubs.org/bulletin/current/history_list/history_part1.pdf , url-status=dead , archive-url=https://web.archive.org/web/20120817014234/http://esapubs.org/bulletin/current/history_list/history_part1.pdf , archive-date=17 August 2012 , access-date=29 September 2010 {{Cite journal , last=Egerton , first=F. N. , title=A history of the ecological sciences, part 23: Linnaeus and the economy of nature , journal=Bulletin of the Ecological Society of America , volume=88 , issue=1 , pages=72–88 , year=2007 , doi=10.1890/0012-9623(2007)88[72:AHOTES]2.0.CO;2, issn=0012-9623, doi-access=free {{Cite journal , last=Egerton , first=Frank N. , title=Understanding food chains and food webs, 1700–1970 , year=2007 , journal=Bulletin of the Ecological Society of America , volume=88 , pages=50–69 , doi=10.1890/0012-9623(2007)88[50:UFCAFW]2.0.CO;2, issn=0012-9623 {{Cite journal , last1=Emmerson , first1=M. , last2=Yearsley , first2=J. M. , title=Weak interactions, omnivory and emergent food-web properties , journal=Philosophical Transactions of the Royal Society B , volume=271 , issue=1537 , pages=397–405 , doi=10.1098/rspb.2003.2592 , pmid=15101699 , year=2004 , url=http://www.ucc.ie/people/memmers/pdfs/Emmerson.Yearsley.Proc.Roy.Soc.B.2004.pdf , url-status=live , archive-url=https://web.archive.org/web/20110606043918/http://www.ucc.ie/people/memmers/pdfs/Emmerson.Yearsley.Proc.Roy.Soc.B.2004.pdf , archive-date=6 June 2011 , pmc=1691599 {{Cite journal , last1=Morgan Ernest , first1=S. K. , last3=Brown , first3=James H. , last4=Charnov , first4=Eric L. , last5=Gillooly , first5=James F. , last6=Savage , first6=Van M. , last7=White , first7=Ethan P. , last8=Smith , first8=Felisa A. , last9=Hadly , first9=Elizabeth A. , title=Thermodynamic and metabolic effects on the scaling of production and population energy use , journal=Ecology Letters , volume=6 , issue=11 , year=2003 , pages=990–995 , url=https://www.msu.edu/~maurerb/Ernest_etal_2003.pdf , doi=10.1046/j.1461-0248.2003.00526.x , last2=Enquist , first2=Brian J. , last10=Haskell , first10=John P. , last11=Lyons , first11=S. Kathleen , last12=Maurer , first12=Brian A. , last13=Niklas , first13=Karl J. , last14=Tiffney , first14=Bruce , url-status=dead , archive-url=https://web.archive.org/web/20110608064515/https://www.msu.edu/~maurerb/Ernest_etal_2003.pdf , archive-date=8 June 2011 , access-date=6 September 2009 {{Cite journal, last1=Etemad-Shahidi , first1=A. , last2=Imberger , first2=J. , title=Anatomy of turbulence in thermally stratified lakes , journal=Limnology and Oceanography , volume=46 , issue=5 , year=2001 , pages=1158–1170 , doi=10.4319/lo.2001.46.5.1158 , bibcode=2001LimOc..46.1158E, doi-access=free {{Cite journal , last1=Evans , first1=D. H. , last2=Piermarini , first2=P. M. , last3=Potts , first3=W. T. W. , title=Ionic transport in the fish gill epithelium , journal=Journal of Experimental Zoology , volume=283 , issue=7 , pages=641–652 , year=1999 , url=http://people.biology.ufl.edu/devans/DHEJEZ.pdf , doi=10.1002/(SICI)1097-010X(19990601)283:7<641::AID-JEZ3>3.0.CO;2-W , url-status=dead , archive-url=https://web.archive.org/web/20100626020505/http://people.biology.ufl.edu/devans/DHEJEZ.pdf , archive-date=26 June 2010 , access-date=9 December 2009 {{Cite journal , last1=Falkowski , first1=P. G. , last2=Fenchel , first2=T. , last3=Delong , first3=E. F. , title=The microbial engines that drive Earth's biogeochemical cycles , pmid=18497287 , journal=Science , volume=320 , issue=5879 , pages=1034–1039 , year=2008 , doi=10.1126/science.1153213 , bibcode=2008Sci...320.1034F , s2cid=2844984 , url=https://eebweb.arizona.edu/faculty/saleska/Ecol596V/Readings/Falkowski.2008_Microbes.biogeochemistry_Science.pdf , access-date=24 October 2017 , archive-date=13 April 2020 , archive-url=https://web.archive.org/web/20200413101733/https://eebweb.arizona.edu/faculty/saleska/Ecol596V/Readings/Falkowski.2008_Microbes.biogeochemistry_Science.pdf , url-status=dead {{Cite journal , last1=Fischer , first1=J. , last2=Lindenmayer , first2=D. B. , last3=Manning , first3=A. D. , title=Biodiversity, ecosystem function, and resilience: ten guiding principles for commodity production landscapes , journal=Frontiers in Ecology and the Environment , volume=4 , issue=2 , pages=80–86 , year=2006 , url=http://www.tecniflora.com.br/1_-_Guidelines_commodity_production.pdf , doi=10.1890/1540-9295(2006)004[0080:BEFART]2.0.CO;2 , issn=1540-9295 , url-status=dead , archive-url=https://web.archive.org/web/20110706154515/http://www.tecniflora.com.br/1_-_Guidelines_commodity_production.pdf , archive-date=6 July 2011 , access-date=2 February 2010 {{Cite journal , last1=Flematti , first1=Gavin R. , last2=Ghisalberti , first2=Emilio L. , last3=Dixon , first3=Kingsley W. , last4=Trengove , first4=R. D. , title=A compound from smoke that promotes seed germination , journal=Science , volume=305 , issue=5686 , page=977 , year=2004 , doi=10.1126/science.1099944 , pmid=15247439, s2cid=42979006 {{Cite journal , last1=Folke , first1=C. , last2=Carpenter , first2=S. , last3=Walker , first3=B. , last4=Scheffer , first4=M. , last5=Elmqvist , first5=T. , last6=Gunderson , first6=L. , title=Regime shifts, resilience, and biodiversity in ecosystem management , journal=Annual Review of Ecology and Systematics , year=2004 , volume=35 , pages=557–581 , doi=10.1146/annurev.ecolsys.35.021103.105711 , url=http://www.colorado.edu/AmStudies/lewis/ecology/ecobiodiver.pdf , last7=Holling , first7=C.S. , jstor=2096802 , url-status=dead , archive-url=https://web.archive.org/web/20121018074852/http://www.colorado.edu/AmStudies/lewis/ecology/ecobiodiver.pdf , archive-date=18 October 2012, citeseerx=10.1.1.489.8717 {{Cite journal , last=Forbes , first=S. , title=The lake as a microcosm , journal=Bulletin of the Scientific Association , pages=77–87 , location=Peoria, IL , year=1887 , url=http://www.uam.es/personal_pdi/ciencias/scasado/documentos/Forbes.PDF , url-status=dead , archive-url=https://web.archive.org/web/20110927181252/http://www.uam.es/personal_pdi/ciencias/scasado/documentos/Forbes.PDF , archive-date=27 September 2011 , access-date=22 December 2009 {{Cite journal, last1=Foster , first1=J. B. , last2=Clark , first2=B. , title=The sociology of ecology: ecological organicism versus ecosystem ecology in the social construction of ecological science, 1926–1935 , journal=Organization & Environment , volume=21 , issue=3 , pages=311–352 , year=2008 , url=http://ibcperu.org/doc/isis/10408.pdf , doi=10.1177/1086026608321632 , s2cid=145482219 , url-status=dead , archive-url=https://web.archive.org/web/20130509135622/http://ibcperu.org/doc/isis/10408.pdf , archive-date=9 May 2013 {{Cite journal , doi=10.2307/1929981 , last=Friederichs , first=K. , title=A definition of ecology and some thoughts about basic concepts , journal=Ecology , volume=39 , issue=1 , pages=154–159 , year=1958, jstor=1929981 {{Cite journal, last1=Friedman , first1=J. , last2=Harder , first2=L. D. , title=Inflorescence architecture and wind pollination in six grass species , journal=Functional Ecology , volume=18 , issue=6 , pages=851–860 , year=2004 , url=http://www.bio.ucalgary.ca/contact/faculty/pdf/FriedmanHarder2004.pdf , doi=10.1111/j.0269-8463.2004.00921.x , s2cid=20160390 , url-status=dead , archive-url=https://web.archive.org/web/20110706210905/http://www.bio.ucalgary.ca/contact/faculty/pdf/FriedmanHarder2004.pdf , archive-date=6 July 2011 {{Cite journal , last=Garren , first=K. H. , title=Effects of fire on vegetation of the southeastern United States , journal=Botanical Review , volume=9 , issue=9 , pages=617–654 , year=1943 , doi=10.1007/BF02872506, s2cid=31619796 {{Cite journal, last1=Gartner , first1=Gabriel E.A. , last2=Hicks , first2=James W. , last3=Manzani , first3=Paulo R. , last4=Andrade , first4=Denis V. , last5=Abe , first5=Augusto S. , last6=Wang , first6=Tobias , last7=Secor , first7=Stephen M. , last8=Garland Jr. , first8=Theodore , display-authors=3 , title=Phylogeny, ecology, and heart position in snakes , journal=Physiological and Biochemical Zoology , volume=83 , issue=1 , pages=43–54 , year=2010 , url=http://www.naherpetology.org/pdf_files/1407.pdf , doi=10.1086/648509 , pmid=19968564 , url-status=dead , archive-url=https://web.archive.org/web/20110716163330/http://www.naherpetology.org/pdf_files/1407.pdf , archive-date=16 July 2011, hdl=11449/21150, s2cid=16332609 , hdl-access=free {{Cite journal , last=Ghilarov , first=A. M. , title=Vernadsky's biosphere concept: an historical perspective , journal=The Quarterly Review of Biology , volume=70 , issue=2 , pages=193–203 , year=1995 , doi=10.1086/418982, jstor=3036242, s2cid=85258634 {{Cite book , last=Gilbert , first=F. S. , title=Insect life cycles: Genetics, evolution, and co-ordination , publisher=Springer-Verlag , year=1990 , location=New York, NY , page=258 , url=https://books.google.com/books?id=2jIgAQAAMAAJ , isbn=0-387-19550-5 , access-date=6 January 2020 , archive-date=1 August 2020 , archive-url=https://web.archive.org/web/20200801074017/https://books.google.com/books?id=2jIgAQAAMAAJ , url-status=live {{Cite journal, last=Gleason , first=H. A. , title=The individualistic concept of the plant association , journal=Bulletin of the Torrey Botanical Club , year=1926 , volume=53 , issue=1 , pages=7–26 , url=http://www.ecologia.unam.mx/laboratorios/comunidades/pdf/pdf%20curso%20posgrado%20Elena/Tema%201/gleason1926.pdf , doi=10.2307/2479933 , jstor=2479933 , url-status=dead , archive-url=https://web.archive.org/web/20110722230444/http://www.ecologia.unam.mx/laboratorios/comunidades/pdf/pdf%20curso%20posgrado%20Elena/Tema%201/gleason1926.pdf , archive-date=22 July 2011 {{Cite journal, last1=Goldblatt , first1=Colin , last2=Lenton , first2=Timothy M. , last3=Watson , first3=Andrew J. , title=Bistability of atmospheric oxygen and the Great Oxidation , journal=Nature , volume=443 , pages=683–686 , year=2006 , url=http://lgmacweb.env.uea.ac.uk/ajw/Reprints/goldblatt_et_al_2006.pdf , doi=10.1038/nature05169 , pmid=17036001 , issue=7112 , bibcode=2006Natur.443..683G , s2cid=4425486 , url-status=dead , archive-url=https://web.archive.org/web/20110820005408/http://lgmacweb.env.uea.ac.uk/ajw/Reprints/goldblatt_et_al_2006.pdf , archive-date=20 August 2011 {{Cite journal , last=Goodland , first=R. J. , title=The tropical origin of ecology: Eugen Warming's jubilee , journal=Oikos , volume=26 , issue=2 , pages=240–245 , year=1975 , doi=10.2307/3543715, jstor=3543715 {{Cite journal , last1=Goubitz , first1=S. , last2=Werger , first2=M. J. A. , last3=Ne'eman , first3=G. , title=Germination response to fire-related factors of seeds from non-serotinous and serotinous cones , journal=Plant Ecology , volume=169 , issue=2 , pages=195–204 , year=2009 , doi=10.1023/A:1026036332277, s2cid=32500454 {{Cite journal , last1=Gould , first1=Stephen J. , last2=Vrba , first2=Elizabeth S. , title=Exaptation–a missing term in the science of form , journal=Paleobiology , volume=8 , issue=1 , year=1982 , pages=4–15 , doi=10.1017/S0094837300004310, s2cid=86436132 {{Cite journal , last=Grace , first=J. , title=Understanding and managing the global carbon cycle , journal=Journal of Ecology , volume=92 , pages=189–202 , year=2004 , doi=10.1111/j.0022-0477.2004.00874.x, issue=2, doi-access=free {{Cite journal , last1=Gross , first1=M. , author-link = Matthias Gross , year=2004 , title=Human geography and ecological sociology: the unfolding of human ecology, 1890 to 1930 – and beyond , journal=Social Science History , volume=28 , issue=4 , pages=575–605 , url=http://ssh.dukejournals.org/cgi/content/abstract/28/4/575 , doi=10.1215/01455532-28-4-575 , s2cid=233365777 , url-status=live , archive-url=https://web.archive.org/web/20110726005931/http://ssh.dukejournals.org/cgi/content/abstract/28/4/575 , archive-date=26 July 2011 {{Cite journal , last=Hamner , first=W. M. , title=The importance of ethology for investigations of marine zooplankton , journal=Bulletin of Marine Science , volume=37 , issue=2 , pages=414–424 , year=1985 , url=http://www.ingentaconnect.com/content/umrsmas/bullmar/1985/00000037/00000002/art00005 , url-status=live , archive-url=https://web.archive.org/web/20110607143812/http://www.ingentaconnect.com/content/umrsmas/bullmar/1985/00000037/00000002/art00005 , archive-date=7 June 2011 {{Cite book , last=Hammond , first=H. , title=Maintaining Whole Systems on the Earth's Crown: Ecosystem-based Conservation Planning for the Boreal Forest , location=Slocan Park, BC , publisher=Silva Forest Foundation , year=2009 , page=380 , url=http://www.silvafor.org/crown , isbn=978-0-9734779-0-0 , url-status=dead , archive-url=https://web.archive.org/web/20091205015923/http://www.silvafor.org/crown , archive-date=5 December 2009 , access-date=31 January 2010 {{Cite journal , last=Hanski , first=I. , title=Metapopulation dynamics , journal=Nature , volume=396 , pages=41–49 , year=1998 , url=http://www.helsinki.fi/~ihanski/Articles/Nature%201998%20Hanski.pdf , doi=10.1038/23876 , issue=6706 , bibcode=1998Natur.396...41H , s2cid=4405264 , url-status=dead , archive-url=https://web.archive.org/web/20101231165339/http://www.helsinki.fi/~ihanski/Articles/Nature%201998%20Hanski.pdf , archive-date=31 December 2010 {{Cite book , editor-last=Hanski , editor-first=I. , editor2-last=Gaggiotti , editor2-first=O. E. , title=Ecology, Genetics and Evolution of Metapopulations , publisher=Elsevier Academic Press , year=2004 , location=Burlington, MA , url=https://books.google.com/books?id=EP8TAQAAIAAJ , isbn=0-12-323448-4 , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318154829/http://books.google.com/books?id=EP8TAQAAIAAJ , url-status=live {{Cite journal, last1=Harder , first1=L. D. , last2=Johnson , first2=S. D. , title=Darwin's beautiful contrivances: evolutionary and functional evidence for floral adaptation , journal=New Phytologist , volume=183 , issue=3 , pages=530–545 , year=2009 , doi=10.1111/j.1469-8137.2009.02914.x , pmid=19552694 , doi-access=free {{Cite journal , doi=10.1007/BF01552263 , first=Hardesty , last=D. L. , title=The niche concept: suggestions for its use in human ecology , journal=Human Ecology , volume=3 , issue=2 , pages=71–85 , year=1975, jstor=4602315, s2cid=84328940 {{Cite journal , last=Hardin , first=G. , s2cid=18542809 , title=The competitive exclusion principal , year=1960 , journal=Science , volume=131 , issue=3409 , pages=1292–1297 , doi=10.1126/science.131.3409.1292 , pmid=14399717, bibcode=1960Sci...131.1292H {{Cite journal, last1=Hairston , first1=N. G. Jr. , last2=Hairston , first2=N. G. Sr. , title=Cause-effect relationships in energy flow, trophic structure, and interspecific interactions , journal=The American Naturalist , volume=142 , issue=3 , pages=379–411 , year=1993 , url=http://limnology.wisc.edu/courses/zoo955/Spring2005/food%20web%20seminar%20papers/hairston93AmNat.pdf , doi=10.1086/285546 , hdl=1813/57238 , s2cid=55279332 , url-status=dead , archive-url=https://web.archive.org/web/20110720120313/http://limnology.wisc.edu/courses/zoo955/Spring2005/food%20web%20seminar%20papers/hairston93AmNat.pdf , archive-date=20 July 2011, hdl-access=free {{Cite journal , last=Hasiotis , first=S. T. , title=Complex ichnofossils of solitary and social soil organisms: Understanding their evolution and roles in terrestrial paleoecosystems , journal=Palaeogeography, Palaeoclimatology, Palaeoecology , volume=192 , issue=2 , pages=259–320 , year=2003 , doi=10.1016/S0031-0182(02)00689-2 , bibcode=2003PPP...192..259H {{Cite journal , last1=Hastings , first1=Alan , last2=Byers , first2=James E. , last3=Crooks , first3=Jeffrey A. , last4=Cuddington , first4=Kim , last5=Jones , first5=Clive G. , last6=Lambrinos , first6=John G. , last7=Talley , first7=Theresa S. , last8=Wilson , first8=William G. , title=Ecosystem engineering in space and time , journal=Ecology Letters , volume=10 , issue=2 , pages=153–164 , year=2007 , doi=10.1111/j.1461-0248.2006.00997.x , pmid=17257103, s2cid=44870405 {{Cite journal , last=Hawkins , first=B. A. , title=Ecology's oldest pattern , journal=Endeavor , volume=25 , issue=3 , pages=133–4 , year=2001 , doi=10.1016/S0160-9327(00)01369-7, pmid=11725309 {{Cite journal , last1=Hector , first1=A. , last2=Hooper , first2=R. , title=Darwin and the first ecological experiment , journal=Science , volume=295 , pages=639–640 , year=2002 , doi=10.1126/science.1064815 , pmid=11809960 , issue=5555, s2cid=82975886 {{Cite journal , last1=Heimann , first1=Martin , last2=Reichstein , first2=Markus , title=Terrestrial ecosystem carbon dynamics and climate feedbacks , journal=Nature , volume=451 , issue=7176 , pages=289–292 , year=2008 , url=http://courses.washington.edu/ocean450/Discussion_Topics_Papers/Heinmann_clim_chng_08.pdf , doi=10.1038/nature06591 , pmid=18202646 , bibcode=2008Natur.451..289H , s2cid=243073 , url-status=live , archive-url=https://web.archive.org/web/20110608072906/http://courses.washington.edu/ocean450/Discussion_Topics_Papers/Heinmann_clim_chng_08.pdf , archive-date=8 June 2011, doi-access=free {{Cite journal , last1=Herre , first1=E. A. , last2=Knowlton , first2=N. , last3=Mueller , first3=U. G. , last4=Rehner , first4=S. A. , title=The evolution of mutualisms: exploring the paths between conflict and cooperation , journal=Trends in Ecology and Evolution , volume=14 , issue=2 , pages=49–53 , year=1999 , url=http://www.biology.lsu.edu/webfac/kharms/HerreEA_etal_1999_TREE.pdf , doi=10.1016/S0169-5347(98)01529-8 , pmid=10234251 , url-status=dead , archive-url=https://web.archive.org/web/20090920093119/http://www.biology.lsu.edu/webfac/kharms/HerreEA_etal_1999_TREE.pdf , archive-date=20 September 2009 {{Cite journal , last1=Hinchman , first1=L. P. , last2=Hinchman , first2=S. K. , title=What we owe the Romantics , journal=Environmental Values , volume=16 , issue=3 , pages=333–354 , year=2007 , doi=10.3197/096327107X228382 {{Cite journal , last=Holling , first=C. S. , title=Understanding the complexity of economic, ecological, and social systems , journal=Ecosystems , volume=4 , issue=5 , pages =390–405 , year=2004 , doi=10.1007/s10021-001-0101-5, s2cid=7432683 {{Cite journal , last=Holling , first=C. S. , title=Resilience and stability of ecological systems , journal=Annual Review of Ecology and Systematics , volume=4 , issue=1 , pages=1–23 , year=1973 , jstor=2096802 , doi=10.1146/annurev.es.04.110173.000245 , s2cid=53309505 , url=http://pure.iiasa.ac.at/26/1/RP-73-003.pdf , access-date=10 August 2019 , archive-date=17 March 2020 , archive-url=https://web.archive.org/web/20200317083102/http://pure.iiasa.ac.at/id/eprint/26/1/RP-73-003.pdf , url-status=live {{Cite journal , last=Hughes , first=J. D. , title=Ecology in ancient Greece , journal=Inquiry , volume=18 , issue=2 , pages=115–125 , year=1975 , doi=10.1080/00201747508601756 {{Cite journal , last=Hughes , first=J. D. , title=Theophrastus as ecologist , journal=Environmental Review , volume=9 , issue=4 , pages=296–306 , year=1985 , doi=10.2307/3984460, jstor=3984460, s2cid=155638387 {{Cite journal , last1=Hughes , first1=D. P. , last2=Pierce , first2=N. E. , last3=Boomsma , first3=J. J. , title=Social insect symbionts: evolution in homeostatic fortresses , journal=Trends in Ecology & Evolution , volume=23 , issue=12 , pages=672–677 , year=2008 , url=http://www.csub.edu/~psmith3/Teaching/discussion3C.pdf , doi=10.1016/j.tree.2008.07.011 , pmid=18951653 , url-status=dead , archive-url=https://web.archive.org/web/20110606133109/http://www.csub.edu/~psmith3/Teaching/discussion3C.pdf , archive-date=6 June 2011 , access-date=28 January 2010 {{Cite journal , last=Hughes , first=A. R. , title=Disturbance and diversity: an ecological chicken and egg problem , journal=Nature Education Knowledge , volume=1 , issue=8 , page=26 , url=http://www.nature.com/scitable/knowledge/library/disturbance-and-diversity-an-ecological-chicken-and-13256228 , url-status=live , archive-url=https://web.archive.org/web/20101205231219/http://www.nature.com/scitable/knowledge/library/disturbance-and-diversity-an-ecological-chicken-and-13256228 , archive-date=5 December 2010 {{Cite journal , last1=Humphreys , first1=N. J. , last2=Douglas , first2=A. E. , title=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 , journal=Applied and Environmental Microbiology , volume=63 , issue=8 , pages=3294–3296 , year=1997 , pmid=16535678 , pmc=1389233, doi=10.1128/AEM.63.8.3294-3296.1997 , bibcode=1997ApEnM..63.3294H {{Cite book , last=Hutchinson , first=G. E. , title=A Treatise on Limnology , publisher=Wiley , year=1957 , location=New York, NY , page=1015 , isbn=0-471-42572-9 {{Cite journal , last=Hutchinson , first=G. E. , title=Concluding remarks , journal=Cold Spring Harbor Symposia on Quantitative Biology , volume=22 , issue=797 , pages=415–427 , year=1957 , doi=10.1101/SQB.1957.022.01.039 , pmid= , pmc= {{Cite journal , last1=Igamberdiev , first1=Abir U. , last2=Lea , first2=P. J. , title=Land plants equilibrate O2 and CO2 concentrations in the atmosphere , journal=Photosynthesis Research , volume=87 , issue=2 , pages=177–194 , year=2006 , url=https://www.mun.ca/biology/igamberdiev/PhotosRes_CO2review.pdf , doi=10.1007/s11120-005-8388-2 , pmid=16432665 , s2cid=10709679 , url-status=dead , archive-url=https://web.archive.org/web/20160303194011/http://www.mun.ca/biology/igamberdiev/PhotosRes_CO2review.pdf , archive-date=3 March 2016 {{cite journal , last1=Irwin , first1=Rebecca E. , last2=Bronstein , first2=Judith L. , last3=Manson , first3=Jessamyn S. , last4=Richardson , first4=Leif , title=Nectar robbing: Ecological and evolutionary perspectives , journal=Annual Review of Ecology, Evolution, and Systematics , year=2010 , volume=41 , issue=2 , pages=271–292 , doi=10.1146/annurev.ecolsys.110308.120330 {{Cite journal , last=Itô , first=Y. , title=Development of ecology in Japan, with special reference to the role of Kinji Imanishi , journal=Journal of Ecological Research , volume=6 , issue=2 , pages=139–155 , year=1991 , doi=10.1007/BF02347158, s2cid=45293729 {{Cite journal , last1=Ives , first1=A. R. , last2=Cardinale , first2=B. J. , last3=Snyder , first3=W. E. , title=A synthesis of subdisciplines: Predator–prey interactions, and biodiversity and ecosystem functioning , journal=Ecology Letters , volume=8 , issue=1 , pages=102–116 , year=2004 , doi=10.1111/j.1461-0248.2004.00698.x , doi-access=free {{Cite journal , last=Jacobsen , first=D. , title=Low oxygen pressure as a driving factor for the altitudinal decline in taxon richness of stream macroinvertebrates , journal=Oecologia , volume=154 , issue=4 , pages=795–807 , year=2008 , doi=10.1007/s00442-007-0877-x , pmid=17960424 , bibcode=2008Oecol.154..795J, s2cid=484645 {{Cite journal , last1=Johnson , first1=J. B. , last2=Omland , first2=K. S. , title=Model selection in ecology and evolution , journal=Trends in Ecology and Evolution , volume=19 , issue=2 , pages=101–108 , year=2004 , url=http://faculty.washington.edu/skalski/classes/QERM597/papers/Johnson%20and%20Omland.pdf , doi=10.1016/j.tree.2003.10.013 , pmid=16701236 , url-status=live , archive-url=https://web.archive.org/web/20121014095941/http://faculty.washington.edu/skalski/classes/QERM597/papers/Johnson%20and%20Omland.pdf , archive-date=14 October 2012, citeseerx=10.1.1.401.777 {{Cite journal , last1=Johnson , first1=M. T. , last2=Strinchcombe , first2=J. R. , title=An emerging synthesis between community ecology and evolutionary biology , journal=Trends in Ecology and Evolution , volume=22 , issue=5 , pages=250–257 , year=2007 , doi=10.1016/j.tree.2007.01.014 , pmid=17296244 {{Cite journal , last1=Jones , first1=Clive G. , last2=Lawton , first2=John H. , last3=Shachak , first3=Moshe , title=Organisms as ecosystem engineers , journal=Oikos , volume=69 , issue=3 , pages=373–386 , year=1994 , doi=10.2307/3545850, jstor=3545850 {{Cite journal , last=Karban , first=R. , title=Plant behaviour and communication , journal=Ecology Letters , volume=11 , issue=7 , pages=727–739 , year=2008 , pmid=18400016 , doi=10.1111/j.1461-0248.2008.01183.x, doi-access=free {{Cite journal , last1=Kastak , first1=D. , last2=Schusterman , first2=R. J. , s2cid=19008897 , title=Low-frequency amphibious hearing in pinnipeds: Methods, measurements, noise, and ecology , journal=Journal of the Acoustical Society of America , volume=103 , issue=4 , pages=2216–2228 , year=1998 , doi=10.1121/1.421367 , pmid=9566340, bibcode=1998ASAJ..103.2216K {{Cite journal , last1=Kiers , first1=E. T. , last2=van der Heijden , first2=M. G. A. , title=Mutualistic stability in the arbuscular mycorrhizal symbiosis: Exploring hypotheses of evolutionary cooperation , journal=Ecology , volume=87 , issue=7 , pages=1627–1636 , year=2006 , url=http://people.umass.edu/lsadler/adlersite/kiers/Kiers_Ecology_2006.pdf , doi=10.1890/0012-9658(2006)87[1627:MSITAM]2.0.CO;2 , pmid=16922314 , issn=0012-9658 , url-status=dead , archive-url=https://web.archive.org/web/20091016034526/http://people.umass.edu/lsadler/adlersite/kiers/Kiers_Ecology_2006.pdf , archive-date=16 October 2009 , access-date=31 December 2009 {{Cite journal , last1=Kiessling , first1=W. , last2=Simpson , first2=C. , last3=Foote , first3=M. , title=Reefs as cradles of evolution and sources of biodiversity in the Phanerozoic , journal=Science , volume=327 , issue=5962 , pages=196–198 , year=2009 , doi=10.1126/science.1182241 , pmid=20056888 , bibcode=2010Sci...327..196K , s2cid=206523585 , url=http://geosci.uchicago.edu/%7Efoote/REPRINTS/SCI2010.pdf , access-date=12 April 2020 , archive-date=12 January 2011 , archive-url=https://web.archive.org/web/20110112054939/http://geosci.uchicago.edu/~foote/REPRINTS/SCI2010.pdf , url-status=live {{Cite journal , last=Kingsland , first=S. , title=Conveying the intellectual challenge of ecology: An historical perspective , journal=Frontiers in Ecology and the Environment , volume=2 , issue=7 , pages=367–374 , year=2004 , url=http://www.isa.utl.pt/dbeb/ensino/txtapoio/HistEcology.pdf , archive-url=https://web.archive.org/web/20110810052252/http://www.isa.utl.pt/dbeb/ensino/txtapoio/HistEcology.pdf , url-status=dead , archive-date=10 August 2011 , doi=10.1890/1540-9295(2004)002[0367:CTICOE]2.0.CO;2 , issn=1540-9295 {{Cite journal , last=Kleese , first=D. A. , title=Nature and nature in Psychology , journal=Journal of Theoretical and Philosophical Psychology , volume=21 , pages=61–79 , year=2001 , doi=10.1037/h0091199 {{Cite journal, last1=Kodric-Brown , first1=A. , last2=Brown , first2=J. H. , title=Truth in advertising: The kinds of traits favored by sexual selection , journal=The American Naturalist , volume=124 , issue=3 , pages=309–323 , year=1984 , url=http://dbs.umt.edu/courses/biol406/readings/Wk6-Kodric-Brown%20and%20Brown%201984.pdf , archive-url=https://web.archive.org/web/20110629193515/http://dbs.umt.edu/courses/biol406/readings/Wk6-Kodric-Brown%20and%20Brown%201984.pdf , url-status=dead , archive-date=29 June 2011 , doi=10.1086/284275, s2cid=28245687 {{Cite journal , last1=Kormandy , first1=E. J. , last2=Wooster , first2=Donald , title=Review: Ecology/economy of nature – synonyms? , journal=Ecology , volume=59 , issue=6 , pages=1292–1294 , year=1978 , doi=10.2307/1938247 , jstor=1938247 {{Cite book , last=Kormondy , first=E. E. , title=Concepts of Ecology , edition=4th , year=1995 , publisher=Benjamin Cummings , isbn=0-13-478116-3 {{Cite journal , last1=Krause , first1=A. E. , last2=Frank , first2=K. A. , last3=Mason , first3=D. M. , last4=Ulanowicz , first4=R. E. , last5=Taylor , first5=W. W. , title=Compartments revealed in food-web structure , year=2003 , journal=Nature , volume=426 , issue=6964 , pages=282–285 , url=http://www.glerl.noaa.gov/pubs/fulltext/2003/20030014.pdf , doi=10.1038/nature02115 , pmid=14628050 , bibcode=2003Natur.426..282K , url-status=dead , archive-url=https://web.archive.org/web/20110813001125/http://www.glerl.noaa.gov/pubs/fulltext/2003/20030014.pdf , archive-date=13 August 2011 , hdl=2027.42/62960 , s2cid=1752696 , access-date=4 June 2011 , hdl-access=free {{Cite book , last1=Krebs , first1=J. R. , last2=Davies , first2=N. B. , title=An Introduction to Behavioural Ecology , publisher=Wiley-Blackwell , year=1993 , page=432 , url=https://books.google.com/books?id=CA31asx7zq4C , isbn=978-0-632-03546-5 , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318142455/http://books.google.com/books?id=CA31asx7zq4C , url-status=live {{Cite journal , last1=Laland , first1=K. N. , last2=Odling-Smee , first2=F. J. , last3=Feldman , first3=M. W. , title=Evolutionary consequences of niche construction and their implications for ecology , journal=Proceedings of the National Academy of Sciences , volume=96 , pages=10242–10247 , year=1999 , doi=10.1073/pnas.96.18.10242 , pmid=10468593 , issue=18 , pmc=17873, bibcode=1999PNAS...9610242L, doi-access=free {{Cite journal , last1=Landhäusser , first1=Simon M. , last2=Deshaies , first2=D. , last3=Lieffers , first3=V. J. , title=Disturbance facilitates rapid range expansion of aspen into higher elevations of the Rocky Mountains under a warming climate , journal=Journal of Biogeography , volume=37 , issue=1 , pages=68–76 , year=2009 , doi=10.1111/j.1365-2699.2009.02182.x, s2cid=82859453 {{Cite journal, last1=Lenton , first1=T. M. , last2=Watson , first2=A. , title=Redfield revisited. 2. What regulates the oxygen content of the atmosphere , journal=Global Biogeochemical Cycles , volume=14 , issue=1 , pages=249–268 , year=2000 , doi=10.1029/1999GB900076 , bibcode=2000GBioC..14..249L , doi-access=free {{Cite journal , last=Levins , first=R. , title=Some demographic and genetic consequences of environmental heterogeneity for biological control , journal=Bulletin of the Entomological Society of America , volume=15 , issue=3 , pages=237–240 , year=1969 , url=https://books.google.com/books?id=8jfmor8wVG4C&pg=PA162 , isbn=978-0-231-12680-9 , doi=10.1093/besa/15.3.237 , access-date=19 November 2020 , archive-date=8 April 2022 , archive-url=https://web.archive.org/web/20220408181207/https://books.google.com/books?id=8jfmor8wVG4C&pg=PA162 , url-status=live {{Cite book , last=Levins , first=R. , editor-last=Gerstenhaber , editor-first=M. , chapter=Extinction , title=Some Mathematical Questions in Biology , year=1970 , pages=77–107 , url=https://books.google.com/books?id=CfZHU1aZqJsC , isbn=978-0-8218-1152-8 , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318164618/http://books.google.com/books?id=CfZHU1aZqJsC , url-status=live {{Cite journal, last=Levin , first=S. A. , title=The problem of pattern and scale in ecology: The Robert H. MacArthur Award , journal=Ecology , volume=73 , issue=6 , pages=1943–1967 , year=1992 , doi=10.2307/1941447 , jstor=1941447 , doi-access=free {{Cite journal , doi=10.1007/s100219900037 , last=Levin , first=S. A. , title=Ecosystems and the biosphere as complex adaptive systems , journal=Ecosystems , volume=1 , issue=5 , pages=431–436 , year=1998 , citeseerx=10.1.1.83.6318, s2cid=29793247 {{Cite book , last1=Levin , first1=S. A. , title=Fragile Dominion: Complexity and the Commons , publisher=Perseus Books , year=1999 , location=Reading, MA , url=https://books.google.com/books?id=FUJsj2KOEeoC , isbn=978-0-7382-0319-5 , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318134738/http://books.google.com/books?id=FUJsj2KOEeoC , url-status=live {{Cite journal , last=Li , first=B. , title=Why is the holistic approach becoming so important in landscape ecology? , journal=Landscape and Urban Planning , volume=50 , issue=1–3 , pages=27–41 , year=2000 , doi=10.1016/S0169-2046(00)00078-5 {{Cite journal, last1=Libralato , first1=S. , last2=Christensen , first2=V. , last3=Pauly , first3=D. , title=A method for identifying keystone species in food web models , journal=Ecological Modelling , volume=195 , issue=3–4 , pages=153–171 , year=2006 , url=http://www.seaaroundus.org/researcher/dpauly/PDF/2005/JournalArticles/MethodIdentifyKeystoneSpeciesFoodWebModels.pdf , doi=10.1016/j.ecolmodel.2005.11.029 , url-status=dead , archive-url=https://web.archive.org/web/20120519082210/http://www.seaaroundus.org/researcher/dpauly/PDF/2005/JournalArticles/MethodIdentifyKeystoneSpeciesFoodWebModels.pdf , archive-date=19 May 2012 {{Cite journal, last1=Liu , first1=J. , last2=Dietz , first2=Thomas , last3=Carpenter , first3=Stephen R. , last4=Folke , first4=Carl , last5=Alberti , first5=Marina , last6=Redman , first6=Charles L. , last7=Schneider , first7=Stephen H. , last8=Ostrom , first8=Elinor , last9=Pell , first9=Alice N. , last10=Lubchenco , first10=Jane , last11=Taylor , first11=William W. , last12=Ouyang , first12=Zhiyun , last13=Deadman , first13=Peter , last14=Kratz , first14=Timothy , last15=Provencher , first15=William , title=Coupled human and natural systems , journal=Ambio: A Journal of the Human Environment , volume=36 , issue=8 , pages=639–649 , year=2009 , url=http://ambio.allenpress.com/archive/0044-7447/36/8/pdf/i0044-7447-36-8-639.pdf , archive-url=https://web.archive.org/web/20110809091026/http://ambio.allenpress.com/archive/0044-7447/36/8/pdf/i0044-7447-36-8-639.pdf , url-status=dead , archive-date=9 August 2011 , doi=10.1579/0044-7447(2007)36[639:CHANS]2.0.CO;2 , issn=0044-7447 , display-authors=9 , pmid=18240679, s2cid=18167083 {{Cite book , last1=Lobert , first1=J. M. , last2=Warnatz , first2=J. , chapter=Emissions from the combustion process in vegetation , title=Fire in the Environment: The Ecological, Atmospheric and Climatic Importance of Vegetation Fires , editor-last=Crutzen , editor-first=P. J. , editor2-last=Goldammer , editor2-first=J. G. , publisher=Wiley , year=1993 , chapter-url=http://jurgenlobert.org/papers_data/Lobert.Warnatz.Wiley.1993.pdf , isbn=978-0-471-93604-6 , url-status=dead , archive-url=https://web.archive.org/web/20090106160042/http://www.jurgenlobert.org/papers_data/Lobert.Warnatz.Wiley.1993.pdf , archive-date=6 January 2009 , access-date=11 December 2009 {{Cite journal , last1=Loehle , first1=C. , last2=Pechmann , first2=Joseph H. K. , title=Evolution: The missing ingredient in systems ecology , journal=The American Naturalist , volume=132 , issue=9 , pages=884–899 , year=1988 , doi=10.1086/284895, jstor=2462267, s2cid=85120393 {{Cite journal , last=Loehle , first=C. , title=Challenges of ecological complexity , journal=Ecological Complexity , volume=1 , issue=1 , pages=3–6 , year=2004 , doi=10.1016/j.ecocom.2003.09.001 {{Cite journal , last1=Lovelock , first1=J. , last2=Margulis , first2=Lynn , author2-link=Lynn Margulis , title=Atmospheric homeostasis by and for the biosphere: The Gaia hypothesis , journal=Tellus , volume=26 , issue=1–2 , pages=2–10 , year=1973 , doi=10.1111/j.2153-3490.1974.tb01946.x, bibcode=1974Tell...26....2L, s2cid=129803613 {{Cite journal , last=Lovelock , first=J. , title=The living Earth , year=2003 , journal=Nature , volume=426, pages=769–770 , doi=10.1038/426769a , pmid=14685210 , issue=6968 , bibcode = 2003Natur.426..769L, s2cid=30308855 {{Cite journal , last1=MacArthur , first1=R. , last2=Wilson , first2=E. O. , title=The Theory of Island Biogeography , location=Princeton, NJ , publisher=Princeton University Press , year=1967 {{Cite book , last1=MacKenzie , last2=D.I. , title=Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence , publisher=Elsevier Academic Press , year=2006 , location=London, UK , page=324 , url=https://books.google.com/books?id=RaCmF9PioCIC , isbn=978-0-12-088766-8 , access-date=27 June 2015 , archive-date=18 March 2015 , archive-url=https://web.archive.org/web/20150318130712/http://books.google.com/books?id=RaCmF9PioCIC , url-status=live {{Cite book , last1=Marsh , first1=G. P. , title=Man and Nature: Physical Geography as Modified by Human Action , publisher=Belknap Press , location=Cambridge, MA , url=https://archive.org/details/manandnatureorp02marsgoog , year=1864 , pagExternal links
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