In the context of infrastructure , open access involves physical infrastructure such as railways and physical telecommunications network plants being made available to clients other than owners, for a fee.
99-449: Garrett James Hardin (April 21, 1915 – September 14, 2003) was an American ecologist and microbiologist . He focused his career on the issue of human overpopulation , and is best known for his exposition of the tragedy of the commons in a 1968 paper of the same title in Science , which called attention to "the damage that innocent actions by individuals can inflict on the environment". He
198-610: A BS in zoology from the University of Chicago in 1936 and a PhD in microbiology from Stanford University in 1941 where his dissertation research addressed symbiosis among microorganisms. Moving to the University of California, Santa Barbara in 1946, he served there as Professor of Human Ecology from 1963 until his (nominal) retirement in 1978. He was among the first members of the Society for General Systems Research . A major focus of his career, and one to which he returned repeatedly,
297-554: A capital and operating kind. Hopefully, the cost of this is less than having to build separate infrastructure. It is in the public interest that access disputes be resolved in an efficient way, so that for example, profits are maximized and therefore income tax on those profits is also maximized. The potential for monopoly infrastructure to charge high fees and provide poor service has long been recognized. Monopolies are often inevitable because of high capital costs, with governments often imposing conditions, in exchange for approval of
396-434: A consequence, he argues that any economy based on long-term compound interest must eventually fail due to the physical and mathematical impossibility of long-term exponential growth on a finite planet. Hardin writes, "At this late date millions of people believe in the fertility of money with an ardor seldom accorded to traditional religious doctrines". He argues that, contrary to some socially-motivated claims, population growth
495-460: 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 tool, it has been criticized for being poorly defined from an operational stance. It is difficult to experimentally determine what species may hold
594-428: A dramatic impact on the ecology of individual species or whole ecosystems. For instance, the replacement of an ant species by another (invasive) ant species has been shown to affect how elephants reduce tree cover and thus the predation of lions on zebras . 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
693-412: A flattened body relative to the main populations that live in open savanna. The population that lives in an isolated rock outcrop hides in crevasses where its flattened body offers a selective advantage. Habitat shifts also occur in the developmental life history of amphibians, and in insects that transition from aquatic to terrestrial habitats. Biotope and habitat are sometimes used interchangeably, but
792-612: 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 emergent and 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
891-504: A joint venture to operate both the BCI mine and the railway connection to the port. As the larger player, Fortescue will run the show. The joint venture gives BC Iron inside information as to how much the railway and port will cost, while Fortescue gains inside information about the mine. In 2010, Mount Gibson Iron spent a total of 20 million dollars to upgrade the ore unloaded at Geraldton . The facility will be open to other users who will pay
990-444: 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 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
1089-408: 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
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#17330932936311188-737: A legacy niche that was constructed before their time. 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 include tropical rainforest , temperate broadleaf and mixed forest , temperate deciduous forest , taiga , tundra , hot desert , and polar desert . Other researchers have recently categorized other biomes, such as
1287-439: A linear successional route, changes might occur quickly or slowly over thousands of years before specific forest successional stages are brought about by biological processes. An ecosystem's area can vary greatly, from tiny to vast. A single tree is of little consequence to the classification of a forest ecosystem, but is critically relevant to organisms living in and on it. Several generations of an aphid population can exist over
1386-439: 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
1485-516: 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
1584-420: A new appreciation for the influence that organisms have on the ecosystem and evolutionary process. The term "niche construction" is more often used in reference to the under-appreciated feedback mechanisms of natural selection imparting forces on the abiotic niche. An example of natural selection through ecosystem engineering occurs in the nests of social insects , including ants, bees, wasps, and termites. There
1683-435: 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
1782-527: A possibly large cost of building their own facility. The Marconi Company was a pioneer of long distance radio communication, which was particularly useful for ships at sea. Marconi was very protective about its costly infrastructure and refused—except for emergencies—to allow other radio companies to share its infrastructure. Even if the message sender was royalty, as in the Deutschland incident of 1902 , they continued to refuse access. Since radio communication
1881-401: 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
1980-561: A regulator. In time of flood and accident which puts a line out of order, compulsory trackage rights may be ordered in the public interest to keep traffic flowing, assuming that alternative routes exist. One of the problems faced by Open Access are fair prices. Consider the Iron Ore minnow BC Iron which seeks access to the Fortescue railway . (Fortescue has declared itself to be an open access operator). BC Iron and Fortescue agreed to set up
2079-477: 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 examines how interactions among species and their environment affect the abundance, distribution and diversity of species within communities. Community ecology
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#17330932936312178-456: 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
2277-402: A specific habitat, such as a cave or a pond, and principles gleaned from small-scale studies are extrapolated to larger systems. Feeding relations require extensive investigations, e.g. 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
2376-464: A toll for such usage. The Oakajee port and railway network is also to be open access. In 2011, GVK has offered to make its proposed railway from the Galilee Basin to Abbot Point as open access to other players. In the telecommunications industry, open access to existing infrastructure, in the form of local loop unbundling , duct sharing , utility pole sharing, and fiber unbundling ,
2475-446: A valuable tool in understanding community ecosystems. Food webs illustrate important principles of ecology : some species have many weak feeding links (e.g., omnivores ) while some are more specialized with fewer stronger feeding links (e.g., primary predators ). Such linkages explain how ecological communities remain stable over time and eventually can illustrate a "complete" web of life. The disruption of food webs may have
2574-441: A whole functional system, such as an ecosystem , cannot be predicted or understood by a simple summation of the parts. "New properties emerge because the components interact, not because the basic nature of the components is changed." Ecological studies are necessarily holistic as opposed to reductionistic . Holism has three scientific meanings or uses that identify with ecology: 1) the mechanistic complexity of ecosystems, 2)
2673-399: A wide array of interacting levels of organization spanning micro-level (e.g., cells ) to a planetary scale (e.g., biosphere ) phenomena . Ecosystems, for example, contain abiotic resources and interacting life forms (i.e., individual organisms that aggregate into populations which aggregate into distinct ecological communities). Because ecosystems are dynamic and do not necessarily follow
2772-485: 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 " Euclidean hyperspace whose dimensions are defined as environmental variables and whose size
2871-504: Is a function of the number of values that the environmental values may assume for which an organism has positive fitness ." Biogeographical patterns and range distributions are explained or predicted through knowledge of a species' traits and niche requirements. Species have functional traits that are uniquely adapted to the ecological niche. A trait is a measurable property, phenotype , or characteristic of an organism that may influence its survival. Genes play an important role in
2970-414: 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
3069-568: Is about real science. Hardin goes on to label those who reflexively argue for growth as "growthmaniacs", and argues against the institutional faith in exponential growth on a finite planet. Typical of Hardin's writing style, he illustrates exponential growth by way of a Biblical metaphor. Using compound interest , or " usury ", he starts from the infamous " thirty pieces of silver " and, using five percent compounded interest, finds that after around 2,000 years, "every man, woman, and child would be entitled to only (!) 160,000 earth-masses of gold". As
Garrett Hardin - Misplaced Pages Continue
3168-639: Is also exponential growth, therefore even a little would be disastrous anywhere in the world, and that even the richest nations are not immune. Hardin, who suffered from a heart disorder and post-polio syndrome , and his wife, Jane, who suffered from Lou Gehrig's disease , were members of End-of-Life Choices , formerly known as the Hemlock Society . Believing in individuals' choice of when to die, they killed themselves in their Santa Barbara home in September 2003, shortly after their 62nd wedding anniversary. He
3267-480: Is also known for Hardin's First Law of Human Ecology: "We can never do merely one thing. Any intrusion into nature has numerous effects, many of which are unpredictable." Hardin held hardline anti-immigrant positions as well as positions on eugenics and multiethnicism that have led multiple sources to label him a white nationalist . The Southern Poverty Law Center described his publications as "frank in their racism and quasi-fascist ethnonationalism". Hardin received
3366-461: Is an emergent homeostasis or homeorhesis in the structure of the nest that regulates, maintains and defends the physiology of the entire colony. Termite mounds, for example, maintain a constant internal temperature through the design of air-conditioning chimneys. The structure of the nests themselves is subject to the forces of natural selection. Moreover, a nest can survive over successive generations, so that progeny inherit both genetic material and
3465-404: 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
3564-438: 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), secondary consumers ( carnivorous predators that feed exclusively on herbivores), and tertiary consumers (predators that feed on
3663-574: Is the Park Grass Experiment , which was initiated in 1856. Another example is the Hubbard Brook study , which has been in operation since 1960. Holism remains a critical part of the theoretical foundation in contemporary ecological studies. Holism addresses the biological organization of life that self-organizes into layers of emergent whole systems that function according to non-reducible properties. This means that higher-order patterns of
3762-413: 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 CO 2 and O 2 composition has been affected by the biogenic flux of gases coming from respiration and photosynthesis, with levels fluctuating over time in relation to
3861-436: 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
3960-522: 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 measure species diversity in grasslands in relation to soil fertility. It might also include the analysis of predator-prey dynamics, competition among similar plant species, or mutualistic interactions between crabs and corals. These ecosystems, as we may call them, are of
4059-552: Is used for managing wildlife stocks and setting harvest quotas. In cases where basic models are insufficient, ecologists may adopt different kinds of statistical methods, such as the Akaike information criterion , or use models that can become mathematically complex as "several competing hypotheses are simultaneously confronted with the data." The concept of metapopulations was defined in 1969 as "a population of populations which go extinct locally and recolonize". Metapopulation ecology
Garrett Hardin - Misplaced Pages Continue
4158-714: The American Eugenics Society dates to 1956, and Hardin served as a director from 1971-1974 (the American Eugenics Society changed its name to the Society for the Study of Social Biology in 1973). In 1968, Hardin applied his conceptual model developed in his essay " The Tragedy of the Commons " to human population growth, the use of the Earth's natural resources , and the welfare state. His essay cited an 1833 pamphlet by
4257-405: The 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 consumers ), and Detritivores (or decomposers ). Autotrophs are organisms that produce their own food (production
4356-436: The logistic equation by Pierre Verhulst : where N(t) is the number of individuals measured as biomass density as a function of time, t , r is the maximum per-capita rate of change commonly known as the intrinsic rate of growth, and α {\displaystyle \alpha } is the crowding coefficient, which represents the reduction in population growth rate per individual added. The formula states that
4455-576: The 2009 Nobel Memorial Prize in Economic Sciences with Oliver E. Williamson . In contrast to Hardin, they stated neither commons or "Allmende" in the generic nor classical meaning are bound to fail; to the contrary "the wealth of the commons" has gained renewed interest in the scientific community. Hardin's work was also criticized as historically inaccurate in failing to account for the demographic transition , and for failing to distinguish between common property and open access resources. Despite
4554-545: The Earth and atmospheric conditions within a narrow self-regulating range of tolerance. 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 the Malthusian growth model which states, "a population will grow (or decline) exponentially as long as
4653-461: The English economist William Forster Lloyd which included an example of herders sharing a common parcel of land, which would lead to overgrazing. Hardin blamed the welfare state for allowing the tragedy of the commons; he claimed that where the state provides for children and supports large families as a fundamental human right, Malthusian catastrophe is inevitable. Hardin stated in his analysis of
4752-705: 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 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
4851-498: 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. 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
4950-617: The criticisms, the theory has nonetheless been influential. In 1993, Garrett Hardin published Living Within Limits: Ecology, Economics, and Population Taboos , which he described at the time as a summation of all his previous works. The book won the 1993 Phi Beta Kappa Award in Science . In the book, he argues that the natural sciences are grounded in the concept of limits (such as the speed of light ), while social sciences, such as economics, are grounded in concepts that have no limits (such as
5049-714: 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 includes species diversity , ecosystem diversity , and genetic diversity and scientists are interested in the way that this diversity affects the complex ecological processes operating at and among these respective levels. Biodiversity plays an important role in ecosystem services which by definition maintain and improve human quality of life. Conservation priorities and management techniques require different approaches and considerations to address
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#17330932936315148-514: 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
5247-452: 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 emergent feedback loop generated by the metabolism of living organisms that maintains the core temperature of
5346-434: 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 . Food chains in an ecological community create a complex food web. Food webs are a type of concept map that is used to illustrate and study pathways of energy and material flows. Empirical measurements are generally restricted to
5445-460: The environment experienced by all individuals in the population remains constant." Simplified population models usually starts with four variables: death, birth, immigration , and emigration . An example of an introductory population model describes a closed population, such as on an island, where immigration and emigration does not take place. Hypotheses are evaluated with reference to a null hypothesis which states that random processes create
5544-451: The equilibrium, r / α {\displaystyle r/\alpha } as K , which is known as the "carrying capacity." Population ecology builds upon these introductory models to further understand demographic processes in real study populations. Commonly used types of data include life history , fecundity , and survivorship, and these are analyzed using mathematical techniques such as matrix algebra . The information
5643-589: The flux of energy and matter through an environment. Ecosystems have biophysical feedback mechanisms that moderate processes acting on living ( biotic ) and abiotic components of the planet. Ecosystems sustain life-supporting functions and provide ecosystem services like biomass production (food, fuel, fiber, and medicine), the regulation of climate , global biogeochemical cycles , water filtration , soil formation , erosion control, flood protection, and many other natural features of scientific, historical, economic, or intrinsic value. The scope of ecology contains
5742-400: The former applies to a community's environment, whereas the latter applies to a species' environment. 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
5841-544: The former relates only to the physical modifications of the habitat whereas the latter also considers the evolutionary implications of physical changes to the environment and the feedback this causes on the process of natural selection. Ecosystem engineers are defined as: "organisms that directly or indirectly modulate the availability of resources to other species, by causing physical state changes in biotic or abiotic materials. In so doing they modify, maintain and create habitats." The ecosystem engineering concept has stimulated
5940-518: The full ecological scope of biodiversity. Natural capital that supports populations is critical for maintaining ecosystem services and species migration (e.g., riverine fish runs and avian insect control) has been implicated as one mechanism by which those service losses are experienced. An understanding of biodiversity has practical applications for species and ecosystem-level conservation planners as they make management recommendations to consulting firms, governments, and industry. The habitat of
6039-408: The herbivore trophic level, food webs are better characterized as a tangled web of omnivores." 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
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#17330932936316138-406: The human and oceanic microbiomes . To a microbe , the human body is a habitat and a landscape. Microbiomes were discovered largely through advances in molecular genetics , which have revealed a hidden richness of microbial diversity on the planet. The oceanic microbiome plays a significant role in the ecological biogeochemistry of the planet's oceans. The largest scale of ecological organization
6237-1078: The individual, population , community , ecosystem , and biosphere levels. Ecology overlaps with the closely related sciences of biogeography , evolutionary biology , genetics , ethology , and natural history . Ecology is a branch of biology , and is the study of abundance , biomass , and distribution of organisms in the context of the environment. It encompasses life processes, interactions, and adaptations ; movement of materials and energy through living communities; successional development of ecosystems; cooperation, competition, and predation within and between species ; and patterns of biodiversity and its effect on ecosystem processes. Ecology has practical applications in conservation biology , wetland management, natural resource management ( agroecology , agriculture , forestry , agroforestry , fisheries , mining , tourism ), urban planning ( urban ecology ), community health , economics , basic and applied science , and human social interaction ( human ecology ). The word ecology ( German : Ökologie )
6336-404: 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
6435-412: The interplay of development and environmental expression of traits. Resident species evolve traits that are fitted to the selection pressures of their local environment. This tends to afford them a competitive advantage and discourages similarly adapted species from having an overlapping geographic range. The competitive exclusion principle states that two species cannot coexist indefinitely by living off
6534-402: The latter focuses on materials and energy fluxes. System behaviors must first be arrayed into different levels of the organization. Behaviors corresponding to higher levels occur at slow rates. Conversely, lower organizational levels exhibit rapid rates. For example, individual tree leaves respond rapidly to momentary changes in light intensity, CO 2 concentration, and the like. The growth of
6633-450: The life sciences. Natural selection , life history , development , adaptation , populations , and inheritance are examples of concepts that thread equally into ecological and evolutionary theory. Morphological, 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,
6732-424: The lifespan of a single leaf. Each of those aphids, in turn, supports diverse bacterial communities. The nature of connections in ecological communities cannot be explained by knowing the details of each species in isolation, because the emergent pattern is neither revealed nor predicted until the ecosystem is studied as an integrated whole. Some ecological principles, however, do exhibit collective properties where
6831-432: 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
6930-535: The most various kinds and sizes. They form one category of the multitudinous physical systems of the universe, which range from the universe as a whole down to the atom. 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
7029-456: The nature of the unique physical environments that shapes the biodiversity within each. A more recent addition to ecosystem ecology are technoecosystems , which are affected by or primarily the result of human activity. 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
7128-573: The niche is called the ecotope , which is defined as the full range of environmental and biological variables affecting an entire species. 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 beaver pond ) to global scales, over time and even after death, such as decaying logs or silica skeleton deposits from marine organisms. The process and concept of ecosystem engineering are related to niche construction , but
7227-495: The number of nitrogen fixers , can lead to disproportionate, perhaps irreversible, changes in the system properties." Biodiversity refers to the variety of life and its processes. It includes the variety of living organisms, the genetic differences among them, the communities and ecosystems in which they occur, and the ecological and evolutionary processes that keep them functioning, yet ever-changing and adapting. Biodiversity (an abbreviation of "biological diversity") describes
7326-399: The observed data. In these island models, the rate of population change is described by: where N is the total number of individuals in the population, b and d are the per capita rates of birth and death respectively, and r is the per capita rate of population change. Using these modeling techniques, Malthus' population principle of growth was later transformed into a model known as
7425-406: 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 architectural feature as the removal of
7524-413: The practical description of patterns in quantitative reductionist terms where correlations may be identified but nothing is understood about the causal relations without reference to the whole system, which leads to 3) a metaphysical hierarchy whereby the causal relations of larger systems are understood without reference to the smaller parts. Scientific holism differs from mysticism that has appropriated
7623-435: The project and for the granting of useful powers such as land resumption . Thus a canal might have its rates regulated, and be forbidden to operate canal boats on its own waters. Where there are many separate railways and one railway wishes to run trains off their own tracks onto the tracks of another, they may seek trackage rights from the other railway(s). This can be done by voluntary agreement, or by compulsory order of
7722-468: The published work of George Perkins Marsh ("Man and Nature"). Within an ecosystem, organisms are linked to the physical and biological components of their environment to which they are adapted. Ecosystems are complex adaptive systems where the interaction of life processes form self-organizing patterns across different scales of time and space. Ecosystems are broadly categorized as terrestrial , freshwater , atmospheric, or marine . Differences stem from
7821-502: The rate of change in population size ( d N ( t ) / d t {\displaystyle \mathrm {d} N(t)/\mathrm {d} t} ) will grow to approach equilibrium, where ( d N ( t ) / d t = 0 {\displaystyle \mathrm {d} N(t)/\mathrm {d} t=0} ), when the rates of increase and crowding are balanced, r / α {\displaystyle r/\alpha } . A common, analogous model fixes
7920-424: The same limiting resource ; one will always out-compete the other. When similarly adapted species overlap geographically, closer inspection reveals subtle ecological differences in their habitat or dietary requirements. Some models and empirical studies, however, suggest that disturbances can stabilize the co-evolution and shared niche occupancy of similar species inhabiting species-rich communities. The habitat plus
8019-629: The same region, the Fortescue Metals Group railway has been set up for open access for a fee. In June 2008 the Federal Government advisory body, the National Competition Council, recommended that BHP Billiton's Goldsworthy railway and Rio Tinto's Hamersley & Robe River railway should be declared open access. Treasurer Wayne Swan was given 60 days to make a final decision based on this recommendation. On October 27
8118-431: The same term. An example of metaphysical holism is identified in the trend of increased exterior thickness in shells of different species. The reason for a thickness increase can be understood through reference to principles of natural selection via predation without the need to reference or understand the biomolecular properties of the exterior shells. Ecology and evolutionary biology are considered sister disciplines of
8217-460: 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. Open access (infrastructure) For example, private railways within a steel works are private and not available to outsiders. In the hypothetical case of the steelworks having a port or a railway to a distant mine, outsiders might want access to save having to incur
8316-399: 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
8415-524: The study of ecology into a conceptually manageable framework, the biological world is organized into a nested hierarchy , ranging in scale from genes , to cells , to tissues , to organs , to organisms , to species , to populations , to guilds , to communities , to ecosystems , to biomes , and up to the level of the biosphere . This framework forms a panarchy and exhibits non-linear behaviors; this means that "effect and cause are disproportionate, so that small changes to critical variables, such as
8514-432: The sum of the components explain the properties of the whole, such as birth rates of a population being equal to the sum of individual births over a designated time frame. The main subdisciplines of ecology, population (or community ) ecology and ecosystem ecology , exhibit a difference not only in scale but also in two contrasting paradigms in the field. The former focuses on organisms' distribution and abundance, while
8613-491: The threat of overpopulation to the Earth's sustainable economic future, called for coercive constraints on "unqualified reproductive rights" and argued that affirmative action is a form of racism . Ecologist Ecology (from Ancient Greek οἶκος ( oîkos ) 'house' and -λογία ( -logía ) 'study of') is the natural science of the relationships among living organisms and their environment . Ecology considers organisms at
8712-545: The three lines were declared with open access to apply from November 20, 2008. This will apply for 20 years under the National Access Regime within the Trade Practices Act 1974 . The declaration does not give a right of access, but provides a third party with recourse if access terms cannot be negotiated with the infrastructure owner. A player seeking access to infrastructure would expect to pay several fees of
8811-447: The tragedy of the commons that "Freedom in a commons brings ruin to all." Environmental historians Joachim Radkau , Alfred Thomas Grove and Oliver Rackham criticized Hardin "as an American with no notion at all how Commons actually work". In addition, Hardin's pessimistic outlook was subsequently contradicted by Elinor Ostrom 's later work on success of co-operative structures like the management of common land , for which she shared
8910-640: The tree responds more slowly and integrates these short-term changes. 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 about broader scale influences, such as atmosphere or climate. Hence, ecologists classify ecosystems hierarchically by analyzing data collected from finer scale units, such as vegetation associations , climate, and soil types , and integrate this information to identify emergent patterns of uniform organization and processes that operate on local to regional, landscape , and chronological scales. To structure
9009-415: The underlying causes of these fluxes. Research in ecosystem ecology might measure primary production (g C/m^2) in a wetland in relation to decomposition and consumption rates (g C/m^2/y). This requires an understanding of the community connections between plants (i.e., primary producers) and the decomposers (e.g., fungi and bacteria). The underlying concept of an ecosystem can be traced back to 1864 in
9108-439: 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 a montane or alpine ecosystem. Habitat shifts provide important evidence of competition in nature where one population changes relative to the habitats that most other individuals of the species occupy. For example, one population of a species of tropical lizard ( Tropidurus hispidus ) has
9207-444: The widespread "infinite-Earth" economic models). He notes that most of the more notable scientific (as opposed to political) debates concerning ecological economics are between natural scientists, such as Paul R. Ehrlich , and economists, such as Julian Simon , one of Ehrlich's most well known and vocal detractors. A strong theme throughout the book is that economics, as a discipline, can be as much about mythology and ideology as it
9306-583: Was 88 and she was 81. Hardin caused controversy for his support of anti-immigrant causes during his lifetime. The Southern Poverty Law Center noted that Hardin served on the board of the Federation for American Immigration Reform and Social Contract Press and co-founded the anti-immigration Californians for Population Stabilization and The Environmental Fund, which according to the SPLC "served to lobby Congress for nativist and isolationist policies". In 1994, he
9405-589: Was coined in 1866 by the German scientist Ernst Haeckel . The science of ecology as we know it today began with a group of American botanists in the 1890s. Evolutionary concepts relating to adaptation and natural selection are cornerstones of modern ecological theory . Ecosystems are dynamically interacting systems of organisms, the communities they make up, and the non-living ( abiotic ) components of their environment. Ecosystem processes, such as primary production , nutrient cycling , and niche construction , regulate
9504-534: Was never fully tested. In 2004 Fortescue Metals Group launched a bid to have the Mount Newman railway owned by BHP Billiton declared for third party access. The owner of the line claimed that they formed an integral part of the production process, and so should not be subject to completion requirements. When these mines started in the 1960s , state laws required the miners to make their infrastructure available to other players, but no application had been made. In
9603-463: Was one of 52 signatories on " Mainstream Science on Intelligence ", an editorial written by Linda Gottfredson and published in the Wall Street Journal , which declared the consensus of the signing scholars on issues related to race and intelligence following the publication of the book The Bell Curve . Hardin's last book The Ostrich Factor: Our Population Myopia (1999), a warning about
9702-484: Was so new, it preceded laws, regulations and licenses, which might otherwise impose conditions to open infrastructure to other players. In the Pilbara region of Western Australia , two large mining companies operate their own private railway networks to bring iron ore from mines to the port. In 1999 North Limited made an application to access Rio Tinto's system, but Rio's takeover of North Limited meant that application
9801-424: Was the issue of human overpopulation . This led to writings on controversial subjects such as advocating abortion rights, which earned him criticism from the political right , and advocating strict limits to all immigration, which earned him criticism from the political left . In his essays, he also tackled subjects such as conservation and creationism . He was also a proponent of eugenics ; his membership in
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