PDF | Human ecology can refer to a variety of disciplinary subfields or to the In book: Encyclopedia of Environment and Society, Volume 3. PDF | IntroductionComparative Human Population EcologyComparative Human Life HistoryHuman In book: Metabolic Ecology, pp Return this book on or before the. Latest Date . Students unfamiliar with the concepts of human ecology will find. Marsten Bates' Man in.
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Concepts and Principles of a Human Ecology Perspective. 3. Prussian geographer, presented this interpretation in his book titled Cosmos. Similarly. (Title of Robert Foley's book on evolutionary human ecology). I. Introduction Human ecology is an approach to the study of human be- havior marked by. Part of the Ecological Studies book series (ECOLSTUD, volume ). Download Pages PDF · Synthesis — Towards a Biocultural Human Ecology.
C h a n g e i n the institutions m a k i n g up the social system in response to LU inputs from the ecosystem—Such change may be either primary, as when IN CO an increase in the death rate due to environmentally transmitted diseases 00 changes the population structure o fa society, or secondary, as other social o system institutions change in response to environmentally generated pri- uJ s 39 0 mary change i n one institution. Social system changes i n response to 4i inputs from the ecosystem may be and often are adaptive, that is, they contribute to the c o n t i n u i n g survival o f the social system under changed e n v i r o n m e n t a l conditions.
T h e y need not, however, result in a better or happier way o f life for individual h u m a n participants. In other words, it is the social system itself, rather than the people who are involved i n it, that is the unit o fnatural selection and adaptation.
C h a n g e s i n the ecosystem in response to inputs from the social system— LU Just as h u m a n society changes i n response to environmental influences, OH so docs the ecosystem change in response to h u m a n influences. In recent years hill slopes in northern India have been deforested ecosystems change by overgrazing by animals and by cutting of trees and 00 CP bushes by people for domestic c o o k i n gfuel.
T h i s has resulted in a severe short- 5? Peasant CO households have responded to this energy crisisby using their children to scav- CO CO enge any available twigs, agricultural litter, and especially, cow d u n g change in resource exploitation pattern. T h i s activityenhances the economic value of children to the household, leading parents to have more children change in population.
Consequent increased population results i n increased h u m a n pressure on the productivityo fthe ecosystem. Intensive collection o fcow d u n g flow o f energy and material from the ecosystem to the social system has, en however, reduced the supply of manure i n the farm fields change in soil com- ponent of the ecosystem with consequent l o w e r i n g o f crop yields change in so plant component o f the ecosystem.
Policy Institute decreased dry-season flow o f irrigation water from the deforested hills and the ihe boundary definition problems inherent in the ecosystem-based model o f clogging of irrigation canals by soil eroded from the denuded hill slopes sec- h u m a n ecology. These reduced yields are reflected T h e r e is no inherent c o n t r a d i c t i o n between the systems model and the in a decreased flow o f food energy and materials to the h u m a n population with actor-based model o f h u m a n ecology.
T h e latter approach is simplyone a m o n g consequent negative consequences for nutritional status and health changes many that can be incorporated w i t h i n the larger social systems framework. Certainly, decision m a k i n g by individual participants affects both the charac- Tf government extension agents introduce biogas generators change i n ter o f the social system and its interactions with he ecosystem, but, as has technology o f the social system resulting from diffusion f r o m another social already been discussed, all such decisions are made w i t h i n the context o f these system , concentrated organic residues are again available for use as manure systems.
T h e solution o f the domestic fuel problem could lead to re- environment. Rather than simply slatting with the idea that environmental duced fuel collection in the uplands change i n flow of energy from the eco- influences must somehow affect humans or that h u m a n actions must somehow system to the social system , which allows regeneration of vegetative cover, influence the e n v i r o n m e n t , it focuses attention on the. S u c h specification pro- of foods for the peasants, and so o n.
L a c k i n g W h e t h e r or not such ecologicalbenefits actually are obtained from introduc- such a systematic m o d e l , h u m a n ecology can continue to produce only the sort tion o f the new technology, however, will be strongly influenced by social of n d h o c results that have essentially characterized the field to date. If biogas plants arc sold to i n d i v i d u a l households, only the wealthier peasant families will be able to afford them.
Poorer peasants are likely to end up collecting d u n g to sell to the biogas plant owners for cash. M o r e reliable supplies o f irrigation water also are likely for analysis of h u m a n interactions with the environment, it is not intended to to benefit differentially the owners o f larger plots l y i n g w i t h i n the c o m m a n d be and should never be used as an operational research model.
T h a t is, no area, again serving to increase economic inequality w i t h i n ihe c o m m u n i t y investigator should simply use the model as ihe basis for m a k i n g a holistic Poorer households, h a v i n g no vested interest in m a i n t a i n i n g the renewed description ofany specific c o m m u n i t y ' s inieraciions with iis ecosystem. Such a watershed, may even deliberately seek to sabotage the w o r k i n g o f the irriga- total description would be as useless as it would be undoable in practice given tion system.
T h i s has i n fact happened i n the case o f he C h a n d i g a r project the immense comple. Instead ofdescribing systems for description's sake, it is much more reward- T h e point o fthis discussion isthat the relationship between the social system ing to siart work with a specific problem as the focus of the research.
T h e virtue o f the systems return 1 0 the earlier example of deforestation in India, one could ask: M o r e o v e r , this approach avoids any neces- supply of irrigation water be increased? T h e systems model therefore overcomes the investigator e. M a n y important insights have already been p r o v i d e d , Prescicntific period thought on human-nature relations is described by changing i n profound ways how people think about the world and their place T h o m a s Systematic research on h u m a n ecology has only really just begun, while the theory is critically reviewed by Piatt and Sprout and Sprout however, and areas o f ignorance far exceed areas o f understanding.
But that is D a r y l l F o r d provided the most detailed presentation of the why the field is such an intellectuallyexcitingone i n which to work. T h e example of the distribution o f maize agriculture i n N o r t h A m e r i c a being limited by climate is from A. T h e articles collected in Steward , particularly C h a p t e r 2, " T h e C o n - cept and M e t h o d o f C u l t u r a l Ecology," as well as his later article , offer clear statements o f the model ofcultural ecology.
Evans-Pritchard's m o n o g r a p h on the N u e r 1 9 4 0 represents a parallel, but independent, effort. Geertz applies the cultural ecologicalapproach to analysis of Indonesian agriculture.
T h e sacred cows of India are discussed from the standpoint ofcultural ecology by M a r v i n H a r r i s , , and O d e n d ' h a l ' s e m p i r i c a lstudy o f the energetics o f Indian cattle supports H a r r i s ' view that they efficiently convert environmental resources into forms useful to m a n.
W h y t e offers a m u c h less favorable assessment o f the role o f cattle in I n d i a. Diencr, N o n i n i , and R o b k i n document the extensive ecological degradation resulting from overgrazing. T h e existence o f the " p i g l i n e " as a bar to the spread o f Islam in Borneo is reported by J. Bolton Information on the ef- fects of reforestation at C h a n d i g a r on irrigation water supplies was provided by P.
T h e ecosystem-based model was formulated by A. Rappaport under the label of "general ecology. M a r g a r e t M a c A r t h u r raises serious objections, however, to his interpretation o f nutritional data while A n d e r s o n questions the suit- ability of the local population as the unit ofecological analysis. O r l o v e presents the clearest discussion of the actor-based mo- del of h u m a n ecology and the label itself was suggested by h i m.
Richerson Johnson statesthe case for the importance of individual decision making with regard to agricultural innovation, while M. Moerman and M. Calavan present empiricalcase studies demonstrating the Anderson, J. Observationsregard- Ecologicalanthropology and anthropological ecology. Ho- ing NorthernVietnamese resettled in the MekongDelta are from the author's nigmann ed. Handbook of Social and C u l t u r a l Anthropology, Hardin's paper, "TheTragedyof the Com- Chicago: That individualsmay make erroneous choices isdocumented in chill- Human ecology.
Kroeber ed. Anthropology Today, UniversityofChicago Press. That there is a real distinction between survival of the individualor Bennett, J. C u l t u r a l Anthropology and H u m a n Adaptation. Diener's essayon the Hufterites. New York: Pergamon Press Inc.
There is no adequate single treatment of the systems model of human ecol- Bolton,J. VonBertalanffy remains the basic work on general systems the- Food taboos among the Orang Asli in West Malaysia: A potential ory while E. Laszio offers one of the more readable introductions to an nutritional hazard. Odum , presentsasys- Calavan, M. A n Anthropological Study of A g r i c u l t u r e i n as an analytic unit, an integrity that is questioned by P.
Colinvaux Special Reports No. Normal Northern Illi- E. Durkheim is the precursor of structural-functional approaches to nois University CenterforSoutheast Asian Studies. That social facts can be explained only in terms of other social facts is Colfer, C. Radcliffe-Brown's Women, men, and time in the forests of East Kalimantan.
Borneo collected essays present the structural-functional approachas developed Research B u l l e t i n 13 2: Leslie White advances the thesis that adapta- Colinvaux, P. JohnWileyand Sons. James Dow presents mathematical models for analyzing Diencr, P. The Hutterite case. A m e r i c a n Ethnologist 1, systems while the present author Rambo explores more qualitative Robkin Asian agriculturalsocieties.
Dow, James Systems models of cultural ecology. Social Science Information 15 6: Durkheim, E. Allen and Unwin, Ltd. FreePress orig. Evans-Pritchard, E. Oxford University Press. Mocrman, M. Allen and Unwin,Ltd. University of California Press.
Forde, C. Netting, R. Addison-Wesley Geertz,C. Modular Publication No. The Process of Ecological Change i n Indonesia.
Mcnlo Park, California: Grossman, L. Hardin, G. Odum, E. Science , 13 Dec: Saunders Harris, M. Current Anthropology 7: The emergence of ecology as a new integrative discipline.
Science Hutch- Orlove, B. Plait, R. A m e r i c a n J o u r n a l of Sociol- Environmentalist! Hilberg, R. Radcliffe-Brown, A. Free Press. Rambo, A. Terry Johnson, A.
H u - Asia. Singapore J o u r n a l of Tropical Geography 3 1: Rappaport, R. Kroeber, A. Univer- Haven: Yale University Press. Damas ed. Contributions to Anthropology: Eco- Laszlo,E. George BrazillerInc. Shapiro Malinowski, B. Revised Edition. Routledge and Sons, Ltd. Richerson, P. Marsh, G. A comparison of theories in the bio- M a n and N a t u r e.
BelknapPress orig. Whyte, R. Praeger ed. Horizons in Anthropology, Aldine Publishing Publishers. Young, G. Seckler, D. A critical inquiry. A rural development program in India. Unpublished In A.
Macfadyen ed. Advances i n Ecological Research Vol. Academic Press Inc. Communities can reap the benefit of this ecological service. Leaving some of these filtering ecosystems intact can reduce the burden on water treatment plants that have been built to perform the same service. By using natural filtering systems, we have the option to build fewer new treatment plants. Biomedical Contributions Ecologists have discovered that many plants and animals produce chemicals that protect them from predators and diseases.
Some of these same chemicals have been synthesized by scientists or harvested from the organism and used to treat human diseases. For example, the Pacific Yew tree produces a substance which is used in cancer treatments.
Another example is a substance found in horseshoe crabs, hemolymph, that is used in leukemia treatments. Lyme Disease An adult deer tick Ixodes scapularis sits on a leaf. Lyme Disease is a potentially serious bacterial infection that is transmitted to humans by certain ticks. Ecological studies have found that people are more likely to get Lyme disease when acorns are plentiful.
Because mice and deer, which carry the disease and the ticks, feed on acorns. More acorns usually mean more mice and deer, providing a favorable environment for large populations of ticks to flourish. Knowing the connections between acorns, deer, mice, and ticks, ecologists are able to predict the likelihood of infection and let people know when they need to be more careful when outdoors.
Natural Resource Management Endangered Species Protection Black-masked member of the weasel family once occurred in central grasslands and basins from southern Canada to Texas but is now one of the most endangered mammals in North America.
These successes are the result of successful captive breeding efforts, reintroduction methods, and a greater understanding of species, in part because of ecological research. Forestry Solutions Graduate student Christina Bielski recorded data during a high intensity prescribed fire burning through juniper-invaded grassland on private property.
Credit, Dirac Twidwell. Ecological concepts have been applied to forest management and are slowly being integrated into traditional forest science. For example, ecological studies have shown that fire plays a key role in maintaining healthy forest ecosystems in certain types of forests. This knowledge has encouraged more research to find ways to use controlled fires to prevent unpredictable and costly wildfires.
Agricultural Solutions Glyphosate fields Biological control is a technique that uses the natural enemies and predators of pests to control damage to crops. It is based in part on knowing the ecology of pests, which is used to understand when and where they are the most vulnerable to their enemies.
Biological control alleviates crop damage by insects, saves money, and decreases problem associated with pesticides. In these island models, the rate of population change is described by:. Using these modelling techniques, Malthus' population principle of growth was later transformed into a model known as the logistic equation:. 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 analysed using mathematical techniques such as matrix algebra.
The information is used for managing wildlife stocks and setting harvest quotas. The concept of metapopulations was defined in  as "a population of populations which go extinct locally and recolonize".
Animal migration is set apart from other kinds of movement; because, it involves the seasonal departure and return of individuals from a habitat. 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 behaviour, stasis, and ranging. Dispersal is usually distinguished from migration; because, it involves the one way permanent movement of individuals from their birth population into another population. 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 favourable.
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. A dynamic metapopulation structure evolves from year to year, where some patches are sinks in dry years and are sources when conditions are more favourable.
Ecologists use a mixture of computer models and field studies to explain metapopulation structure. Community ecology is the study of the interactions among a collections 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. Tansley : 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. Ecosystem ecologist attempt to determine the underlying causes of these fluxes. This requires an understanding of the community connections between plants i. The underlying concept of ecosystem can be traced back to in the published work of George Perkins Marsh "Man and Nature".
Differences stem from 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 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 studies are extrapolated to larger systems.
Food webs exhibit principles of ecological emergence through the nature of trophic relationships: Theoretical and empirical studies identify non-random emergent patterns of few strong and many weak linkages that explain how ecological communities remain stable over time. This increases food web stability. 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 abundance or biomass at each level.
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 is greater than respiration by photosynthesis or chemosynthesis. Heterotrophs are organisms that must feed on others for nourishment and energy respiration exceeds production.
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.
This has led some ecologists to "reiterate that the notion that species clearly aggregate into discrete, homogeneous trophic levels is fiction. 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 that alters trophic dynamics, other food web connections, and can cause the extinction of other species. 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. 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 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. 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 a whole functional system, such as an ecosystem , cannot be predicted or understood by a simple summation of the parts. Ecological studies are necessarily holistic as opposed to reductionistic.
Scientific holism differs from mysticism that has appropriated 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 need to reference or understand the biomolecular properties of the exterior shells.
Ecology and evolutionary biology are considered sister disciplines of the life sciences. Natural selection , life history , development , adaptation , populations , and inheritance are examples of concepts that thread equally into ecological and evolutionary theory. Morphological, 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 principals, such as phylogenetics or the Linnaean system of taxonomy. Both disciplines discover and explain emergent and unique properties and processes operating across different spatial or temporal scales of organization.
All organisms can exhibit behaviours. Even plants express complex behaviour, including memory and communication. 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 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.
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. Elaborate sexual 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 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.
With consideration of the selection pressure on cognition, cognitive ecology can contribute intellectual coherence to the multidisciplinary study of cognition. 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 clones that share the same genetic make-up as every other male in the colony. Groups with predominantly altruistic members survive better than groups with predominantly selfish members.
Ecological interactions can be classified broadly into a host and an associate relationship. A host is any entity that harbours another that is called the associate. 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.
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.
Although parasites impose a cost to their host e. 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 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.
Wilson in  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. The biogeographic processes that result in the natural splitting of species explains much of the modern distribution of the Earth's biota.
The splitting of lineages in a species is called vicariance biogeography and it is a sub-discipline of biogeography. For example, the range and distribution of biodiversity and invasive species responding to climate change is a serious concern and active area of research in the context of global warming.
For example, when an island is first colonized, density of individuals is low. The initial increase in population size is not limited by competition, leaving an abundance of available resources for rapid population growth. These early phases of population growth experience density-independent forces of natural selection, which is called r -selection. As the population becomes more crowded, it approaches the island's carrying capacity, thus forcing individuals to compete more heavily for fewer available resources.
Under crowded conditions, the population experiences density-dependent forces of natural selection, called K -selection. An r -selected species is one that has high birth rates, low levels of parental investment, and high rates of mortality before individuals reach maturity. Evolution favours high rates of fecundity in r -selected species. Many kinds of insects and invasive species exhibit r -selected characteristics.
In contrast, a K -selected species has low rates of fecundity, high levels of parental investment in the young, and low rates of mortality as individuals mature. Humans and elephants are examples of species exhibiting K -selected characteristics, including longevity and efficiency in the conversion of more resources into fewer offspring. The important relationship between ecology and genetic inheritance predates modern techniques for molecular analysis.
Molecular ecological research became more feasible with the development of rapid and accessible genetic technologies, such as the polymerase chain reaction PCR. The rise of molecular technologies and influx of research questions into this new ecological field resulted in the publication Molecular Ecology in In , John Avise also played a leading role in this area of science with the publication of his book, Molecular Markers, Natural History and Evolution.
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. Rachel Carson, "Silent Spring" . Ecology is as much a biological science as it is a human science.
A truly interdisciplinary human ecology will most likely address itself to all three. 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.
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 - natural capital , which provides the means to put a value on the stock and use of information and materials stemming from 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.
Grumbine : 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 that the 21st century "will be the era of restoration in ecology".
Natural resource managers, in forestry , for example, employ ecologists to develop, adapt, and implement ecosystem based methods into the planning, operation, and restoration phases of land-use.
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. The environment of ecosystems includes both physical parameters and biotic attributes.
It is dynamically interlinked, and contains resources for organisms at any time throughout their life cycle. Environment "includes the physical world, the social world of human relations and the built world of human creation.
The biotic environment includes genes, cells, organisms, members of the same species conspecifics and other species that share a habitat. The distinction between external and internal environments, however, is an abstraction parsing life and environment into units or facts that are inseparable in reality. There is an interpenetration of cause and effect between the environment and life.
The laws of thermodynamics , for example, apply to ecology by means of its physical state. With an understanding of metabolic and thermodynamic principles, a complete accounting of energy and material flow can be traced through an ecosystem.
In this way, the environmental and ecological relations are studied through reference to conceptually manageable and isolated material parts. After the effective environmental components are understood through reference to their causes; however, they conceptually link back together as an integrated whole, or holocoenotic system as it was once called. This is known as the dialectical approach to ecology. The dialectical approach examines the parts, but integrates the organism and the environment into a dynamic whole or umwelt.
Change in one ecological or environmental factor can concurrently affect the dynamic state of an entire ecosystem. 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. These disturbances create places of renewal where new directions emerge from the patchwork of natural experimentation and opportunity. Biodiversity fuels the resilience of ecosystems acting as a kind of regenerative insurance. Ernest et al. The Earth was formed approximately 4. 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 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. Early forms of fermentation also increased levels of atmospheric methane. The transition to an oxygen-dominant atmosphere the Great Oxidation did not begin until approximately 2.
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, and primary production. Temperature is largely dependent on the incidence of solar radiation. The latitudinal and longitudinal spatial variation of temperature greatly affects climates and consequently the distribution of biodiversity and levels of primary production in different ecosystems or biomes across the planet.
Heat and temperature relate importantly to metabolic activity. Poikilotherms , for example, have a body temperature that is largely regulated and dependent on the temperature of the external environment. In contrast, homeotherms regulate their internal body temperature by expending metabolic energy. There is a relationship between light, primary production, and ecological energy budgets.
Sunlight is the primary input of energy into the planet's ecosystems. Light is composed of electromagnetic energy of different wavelengths. Radiant energy from the sun generates heat, provides photons of light measured as active energy in the chemical reactions of life, and also acts as a catalyst for genetic mutation.
Organisms capable of assimilating energy by photosynthesis or through inorganic fixation of H 2 S are autotrophs. Autotrophs—responsible for primary production—assimilate light energy which becomes metabolically stored as potential energy in the form of biochemical enthalpic bonds. Diffusion of carbon dioxide and oxygen is approximately 10, times slower in water than in air.
Water also influences the intensity and spectral composition of light as it reflects off the water surface and submerged particles. For example, their roots and stems contain large air spaces aerenchyma that regulate the efficient transportation of gases for example, CO 2 and O 2 used in respiration and photosynthesis.
Salt water plants halophytes have additional specialized adaptations, such as the development of special organs for shedding salt and osmoregulating their internal salt NaCl concentrations, to live in estuarine , brackish , or oceanic environments. Anaerobic soil microorganisms in aquatic environments use nitrate , manganese ions , 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 oxidation-reduction potentials of the water. Carbon dioxide, for example, is reduced to methane CH 4 by methanogenic bacteria. Their gills form electrochemical gradients that mediate salt excretion in salt water and uptake in fresh water. The shape and energy of the land is 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 and erosion.
These forces govern many of the geophysical properties and distributions of ecological biomes across the Earth. On the organismal scale, gravitational forces provide directional cues for plant and fungal growth gravitropism , orientation cues for animal migrations, and influence the biomechanics and size of animals.
Climatic and osmotic pressure places physiological constraints on organisms, especially those that fly and respire at high altitudes, or dive to deep ocean depths. For example, diving animals such as whales , dolphins , and seals are specially adapted to deal with changes in sound due to water pressure differences. 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, 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. Plants convert carbon dioxide into biomass and emit oxygen into the atmosphere.
Fire is a significant ecological parameter that raises many issues pertaining to its control and suppression. 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.
Plants, for example, are equipped with a variety of adaptations to deal with forest fires. Some species e. Environmentally triggered germination of seeds is called serotiny. 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.
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 feed 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. Other events, such as the evolution of trees and the colonization of land in the Devonian period played a significant role in the early development of ecological trophism in soils. Ecologists study and measure nutrient budgets to understand how these materials are regulated, flow, and recycled through the environment.
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, gigatonnes Gt of carbon, that vegetation and soil hold Gt, and that fossil fuel emissions are 6. 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, C 4 photosynthesis , and expanded their ranges. This new pathway evolved in response to the drop in atmospheric CO 2 concentrations below ppm.
Human-driven modifications to the planet's ecosystems e. 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 CH 4 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 CO 2 on a year time scale.
Ernst Haeckel : Ecology has a complex origin, due in large part to its interdisciplinary nature.
However, they viewed life in terms of essentialism , where species were conceptualized as static unchanging things while varieties were seen as aberrations of an idealized type.
This contrasts against the modern understanding of ecological theory where varieties are viewed as the real phenomena of interest and having a role in the origins of adaptations by means of natural selection.
Basking Nile crocodiles , he noted, would open their mouths to give sandpipers safe access to pluck leeches out, giving nutrition to the sandpiper and oral hygiene for the crocodile. He and his student Theophrastus made extensive observations on plant and animal migrations, biogeography, physiology, and on their behaviour, giving an early analogue to the modern concept of an ecological niche. Stephen Forbes .
Ecological concepts such as food chains, population regulation, and productivity were first developed in the s, through the published works of microscopist Antoni van Leeuwenhoek — and botanist Richard Bradley ?
Humboldt drew inspiration from Isaac Newton as he developed a form of "terrestrial physics". In Newtonian fashion, he brought a scientific exactitude for measurement into natural history and even alluded to concepts that are the foundation of a modern ecological law on species-to-area relationships.
Opinions differ on who was the founder of modern ecological theory. Some mark Haeckel's definition as the beginning;  others say it was Eugenius Warming with the writing of Oecology of Plants: An Introduction to the Study of Plant Communities ,  or Carl Linnaeus ' principles on the economy of nature that matured in the early 18th century.
Haeckel, who admired Darwin's work, defined ecology in reference to the economy of nature, which has led some to question whether ecology and the economy of nature are synonymous. From Aristotle until Darwin, the natural world was predominantly considered static and unchanging. Prior to The Origin of Species , there was little appreciation or understanding of the dynamic and reciprocal relations between organisms, their adaptations, and the environment.
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 may have first introduced the term " oekology " which eventually morphed into home economics in the U. In the early 20th century, ecology transitioned from a more descriptive form of natural history to a more analytical form of scientific natural history. This publication launched a debate between ecological holism and individualism that lasted until the s.
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 idealistic form of holism. Elton's 'food cycle' was replaced by 'food web' in a subsequent ecological text.
Lotka brought in many theoretical concepts applying thermodynamic principles to ecology. In , Raymond Lindeman wrote a landmark paper on the 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 s, which inspired a resurgent school of theoretical mathematical ecologists.