The word "ecology" is often used in common parlance as a synonym for the natural environment or environmentalism.

Ecology, or ecological science, is the scientific study of the distribution and abundance of living organisms and how these properties are affected by interactions between the organisms and their environment. The environment of an organism includes both the physical properties, which can be described as the sum of local abiotic factors like solar insolation, climate and geology, as well as the other organisms that share its habitat. The term oekologie was coined in 1866 by the German biologist Ernst Haeckel; the word is derived from the Greek oikos ("household") and logos ("study"); therefore "ecology" means the "study of the household [of nature]". The Natural Environment comprises all living and non-living things that occur naturally on Earth. ... Environmentalism is the support of or involvement with the environmental movement by environmentalists. ... Look up life and living in Wiktionary, the free dictionary. ... Interaction is a kind of action which occurs as two or more objects have an effect upon one another. ... In English medieval great houses and castles, the main room was known as the Great Hall, in which all parts of the household would eat and live, with those of highest status being at the end, often on a raised dais, and those of lesser status further down the hall. ... TOA and surface insolation, annual mean Insolation is the incoming solar radiation that reaches a planet and its atmosphere or, by extension, any object exposed to solar rays, such as watts per square meter of Sun-facing cross section, across the entire electromagnetic spectrum; most of that power is in... Geology (from Greek γη- (ge-, the earth) and λογος (logos, word, reason)) is the science and study of the Earth, its composition, structure, physical properties, history and the processes that shape it. ... Habitat (from the Latin for it inhabits) is the place where a particular species lives and grows. ... 1866 (MDCCCLXVI) is a common year starting on Monday of the Gregorian calendar or a common year starting on Wednesday of the 12-day-slower Julian calendar. ... This article is in need of attention from an expert on the subject. ...

Scope

Ecology is usually considered a branch of biology, the general science that studies living organisms. Organisms can be studied at many different levels, from proteins and nucleic acids (in biochemistry and molecular biology), to cells (in cellular biology), to individuals (in botany, zoology, and other similar disciplines), and finally at the level of populations, communities, and ecosystems, to the biosphere as a whole; these latter strata are the primary subjects of ecological inquiries. Ecology is a multi-disciplinary science. Because of its focus on the higher levels of the organization of life on earth and on the interrelations between organisms and their environment, ecology draws heavily on many other branches of science, especially geology and geography, meteorology, pedology, chemistry, and physics. Thus, ecology is said to be a holistic science, one that over-arches older disciplines such as biology which in this view become sub-disciplines contributing to ecological knowledge. Biology is a branch of science, dealing with the study of life. ... In biology and ecology, an organism (in Greek organon = instrument) is a complex adaptive system of organs that influence each other in such a way that they function as a more or less stable whole and have properties of life. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Schematic diagram of a double-stranded nucleic acid. ... Biochemistry is the study of the chemistry of life, a bridge between biology and chemistry that studies how complex chemical reactions give rise to life. ... Molecular biology is the study of biology at a molecular level. ... Cells in culture, stained for keratin (red) and DNA (green). ... Cell biology (cellular biology) is an academic discipline which studies the physiological properties of cells, as well as their behaviours, interactions, and environment; this is done both on a microscopic and molecular level. ... Botany is the scientific study of plantlife. ... Zoology (Greek zoon = animal and logos = word) is the biological discipline which involves the study of animals. ... In ecology, the word ecosystem is an abbreviation of the term, ecological system. ... The biosphere is that part of a planets outer shell — including air, land, surface rocks and water — within which life occurs, and which biotic processes in turn alter or transform. ... Interdisciplinary work is that which integrates concepts across different disciplines. ... Geology (from Greek γη- (ge-, the earth) and λογος (logos, word, reason)) is the science and study of the Earth, its composition, structure, physical properties, history and the processes that shape it. ... Satellite image of Hurricane Hugo with a polar low visible at the top of the image. ... Pedology (pědǒlōgy), (from Russian: pedologiya, from the Greek pedon = soil, earth), is the study of soils and soil formation. ... Multicolored chemicals are frequent hallmarks of chemistry. ... A Superconductor demonstrating the Meissner Effect. ... Holistic Science is the science of wholes; a whole is a cyclical process or nonlinear, within a self-organized boundary or form that is nested within other interacting wholes; the ongoing relationships of which may be described quantitatively or descriptively by scientists as active participants. ...

Agriculture, fisheries, forestry, medicine and urban development are among human activities that would fall within Krebbs' (1972: 4) explanation of his definition of ecology: "where organisms are found, how many occur there, and why".

As a scientific discipline, ecology does not dictate what is "right" or "wrong". However, ecological knowledge such as the quantification of biodiversity and population dynamics have provided a scientific basis for expressing the goals of environmentalism and evaluating its goals and policies. Additionally, a holistic view of nature is stressed in both ecology and environmentalism. Rainforests are the most biodiverse ecosystems on earth Biodiversity or biological diversity is the diversity of life. ... Population dynamics is the study of marginal and long-term changes in the numbers, individual weights and age composition of individuals in one or several populations, and biological and environmental processes influencing those changes. ... Environmentalism is the support of or involvement with the environmental movement by environmentalists. ... Holism (from holos, a Greek word meaning all, entire, total) is the idea that all the properties of a given system (biological, chemical, social, mental, linguistic, etc. ...

Consider the ways an ecologist might approach studying the life of honeybees:

• the behavioral relationship between individuals of a species is behavorial ecology — for example, the study of the queen bee, and how she relates to the worker bees and the drones.

• The organized activity of a species is community ecology; for example, the activity of bees assures the pollination of flowering plants. Bee hives additionally produce honey which is consumed by still other species, such as bears.
• The relationship between the environment and a species is environmental ecology — for example, the consequences of environmental change on bee activity. Bees may die out due to environmental changes (see pollinator decline). The environment simultaneously affects and is a consequence of this activity and is thus intertwined with the survival of the species.

In biology, a species is the basic unit of biodiversity. ... For the Queen bee in clique & social groups, see Clique. ... Families Andrenidae Apidae Colletidae Halictidae Heterogynaidae Megachilidae Melittidae Oxaeidae Stenotritidae Bee collecting pollen Bees (Apoidea superfamily) are flying insects, closely related to wasps and ants. ... Drones are male honeybees. ... A flower-fly pollinating a Common Daisy (Bellis perennis) Pollination is an important step in the reproduction of seed plants: the transfer of pollen grains (male gametes) to the plant carpel, the structure that contains the ovule (female gamete). ... Classes Magnoliopsida- Dicots Liliopsida- Monocots The flowering plants (also called angiosperms) are a major group of land plants. ... Honey honey comb A capped frame of honeycomb Honey is a sweet and viscous fluid produced by bees and other insects from the nectar of flowers. ... Genera Ailuropoda Ursus Tremarctos Arctodus(extinct) A bear is a very large mammal of the order Carnivora, family Ursidae. ... Pollinator decline is based on observations made at the end of the twentieth century of the reduction in abundance of pollinators in many ecosystems worldwide. ...

Disciplines of ecology

Main article: Disciplines of ecology

Ecology is a broad discipline comprised of many sub-disciplines. A common, broad classification, moving from lowest to highest complexity, where complexity is defined as the number of entities and processes in the system under study, is: Ecology is a broad science which can be subdivided into major and minor sub-disciplines. ...

• Physiological Ecology (or ecophysiology) and Behavioral ecology examine adaptations of the individual to its environment.
• Population ecology (or autecology) studies the dynamics of populations of a single species.
• Community ecology (or synecology) focuses on the interactions between species within an ecological community.
• Ecosystem ecology studies the flows of energy and matter through the biotic and abiotic components of ecosystems.
• Landscape ecology examines processes and relationship across multiple ecosystems or very large geographic areas.

Ecology can also be sub-divided according to the species of interest into fields such as animal ecology, plant ecology, insect ecology, and so on. Another frequent method of subdivision is by biome studied, e.g., Arctic ecology (or polar ecology), tropical ecology, desert ecology, etc. The primary technique used for investigation is often used to subdivide the discipline into groups such as chemical ecology, genetic ecology, field ecology, statistical ecology, theoretical ecology, and so forth. Note that these different systems are unrelated and often applied at the same time; one could be a theoretical plant community ecologist, or a polar ecologist interested in animal genetics. Behavioral ecology is the study of the ecological and evolutionary basis for animal behavior, and the roles of behavior in enabling an animal to adapt to its environment (both intrinsic and extrinsic). ... Population ecology is a major subfield of ecology—one that deals with the dynamics of species populations and how these populations interact with the environment. ... Community ecology is the study of the distribution, abundance, demography, and interactions between populations coexisting species. ... Ecosystem ecology is the study of the movement of energy and matter through ecosystems. ... In ecology, the word ecosystem is an abbreviation of the term, ecological system. ... Landscape ecology is a subdiscipline of ecology and geography that is the study of spatial variation in interested in the of elements in the landscape (such as fields, hedgerows, woodlots, rivers or towns) and how their distribution affects the distribution and flow of energy and individuals in the environment (which... In ecology, a biome is a major regional group of distinctive plant and animal communities best adapted to the regions physical natural environment, latitude, altitude and terrain factors. ... Polar ecology is the study of the interactions between organisms living in the polar regions of the Earth, both in the Arctic and Antarctic regions. ... The Earth is made up of distict regions that share unique characteristics of latitude, soil, climate, and plant and animal poplulations that have evolved to adapt to the particular environment of the region. ... Chemical ecology is the study of the chemicals involved in the interactions of living organisms. ... Theoretical ecology refers to several intellectual traditions. ...

History of ecology

Main article: History of ecology

ÛEcology is generally spoken of as a new science, having only become prominent in the second half of the 20th Century. ...

Fundamental principles of ecology

Biosphere and biodiversity

Main articles: Biosphere, Biodiversity, Unified neutral theory of biodiversity The biosphere is that part of a planets outer shell — including air, land, surface rocks and water — within which life occurs, and which biotic processes in turn alter or transform. ... Rainforests are the most biodiverse ecosystems on earth Biodiversity or biological diversity is the diversity of life. ... The unified neutral theory of biodiversity and biogeography (here Unified Theory or UNTB) is a theory and the title of a monograph[1] by ecologist Stephen Hubbell. ...

For modern ecologists, ecology can be studied at several levels: population level (individuals of the same species), biocoenosis level (or community of species), ecosystem level, and biosphere level. A biocoenosis (alternatively, biocoenose or biocenose), termed by Karl Möbius in 1877, describes all the interacting organisms living together in a specific habitat (or biotope). ... In ecology, the word ecosystem is an abbreviation of the term, ecological system. ... The biosphere is that part of a planets outer shell — including air, land, surface rocks and water — within which life occurs, and which biotic processes in turn alter or transform. ...

The outer layer of the planet Earth can be divided into several compartments: the hydrosphere (or sphere of water), the lithosphere (or sphere of soils and rocks), and the atmosphere (or sphere of the air). The biosphere (or sphere of life), sometimes described as "the fourth envelope", is all living matter on the planet or that portion of the planet occupied by life. It reaches well into the other three spheres, although there are no permanent inhabitants of the atmosphere. Relative to the volume of the Earth, the biosphere is only the very thin surface layer which extends from 11,000 meters below sea level to 15,000 meters above. Hydrosphere (Greek hydro means water) in physical geography, describes the collective mass of water found on, under, and over the surface of a planet. ... The tectonic plates of the Lithosphere on Earth. ... Layers of Atmosphere (NOAA) Earths atmosphere is a layer of gases surrounding the planet Earth and retained by the Earths gravity. ... The biosphere is that part of a planets outer shell — including air, land, surface rocks and water — within which life occurs, and which biotic processes in turn alter or transform. ...

It is thought that life first developed in the hydrosphere, at shallow depths, in the photic zone. (Although recently a competing theory has emerged, that life originated around hydrothermal vents in the deeper ocean. See Origin of life.) Multicellular organisms then appeared and colonized benthic zones. Photosynthetic organisms gradually produced the chemically unstable oxygen-rich atmosphere that characterizes our planet. Terrestrial life developed later, after the ozone layer protecting living beings from UV rays formed. Diversification of terrestrial species is thought to be increased by the continents drifting apart, or alternately, colliding. Biodiversity is expressed at the ecological level (ecosystem), population level (intraspecific diversity), species level (specific diversity), and genetic level. Recently technology has allowed the discovery of the deep ocean vent communities. This remarkable ecological system is not dependent on sunlight but bacteria, utilising the chemistry of the hot volcanic vents, are at the base of its food chain. The photic zone is the depth of the water, whether in a lake or an ocean, that is exposed to sufficient sunlight for photosynthesis to occur. ... Hydrothermal vents are fissures in a planets surface from which geothermally heated water issues. ... Pre-Cambrian stromatolites in the Siyeh Formation, Glacier National Park. ... In oceanography, marine geology and biology, benthos are the organisms and habitats of the sea floor; in freshwater biology they are the organisms and habitats of the bottoms of lakes, rivers, and creeks. ... Orders The taxonomy of the Cyanobacteria is currently under revision. ... The ozone layer, or ozonosphere layer (rarely used term), is that part of the Earths atmosphere which contains relatively high concentrations of ozone (O3). ... Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-rays. ... Portrayal of shifting continents The concept of continental drift was first proposed by Alfred Wegener. ...

The biosphere contains great quantities of elements such as carbon, nitrogen and oxygen. Other elements, such as phosphorus, calcium, and potassium, are also essential to life, yet are present in smaller amounts. At the ecosystem and biosphere levels, there is a continual recycling of all these elements, which alternate between the mineral and organic states. General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... This article is about the chemical element. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Atomic mass 39. ... Look up life and living in Wiktionary, the free dictionary. ...

While there is a slight input of geothermal energy, the bulk of the functioning of the ecosystem is based on the input of solar energy. Plants and photosynthetic microorganisms convert light into chemical energy by the process of photosynthesis, which creates glucose (a simple sugar) and releases free oxygen. Glucose thus becomes the secondary energy source which drives the ecosystem. Some of this glucose is used directly by other organisms for energy. Other sugar molecules can be converted to other molecules such as amino acids. Plants use some of this sugar, concentrated in nectar to entice pollinators to aid them in reproduction. Solar power describes a number of methods of harnessing energy from the light of the sun. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of any wavelength. ... Leaf. ... Glucose (Glc), a monosaccharide, is one of the most important carbohydrates. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... In chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. ... Nectar, in botany, is a juice produced by flowering plants which serves to lure pollinators (though sometimes to lure prey). ...

Cellular respiration is the process by which organisms (like mammals) break the glucose back down into its constituents, water and carbon dioxide, thus regaining the stored energy the sun originally gave to the plants. The proportion of photosynthetic activity of plants and other photosynthesizers to the respiration of other organisms determines the specific composition of the Earth's atmosphere, particularly its oxygen level. Global air currents mix the atmosphere and maintain nearly the same balance of elements in areas of intense biological activity and areas of slight biological activity. Cellular respiration is the process in which the chemical bonds of energy-rich molecules such as glucose are converted into energy usable for life processes. ... Orders Subclass Multituberculata (extinct) Plagiaulacida Cimolodonta Subclass Palaeoryctoides (extinct) Subclass Triconodonta (extinct) Subclass Eutheria (includes extinct ancestors)/Placentalia (excludes extinct ancestors) Afrosoricida Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Litopterna (extinct) Macroscelidea Mesonychia (extinct) Notoungulata (extinct) Perissodactyla Pholidota Plesiadapiformes... A girl in a swimming pool Water (from the Old English waeter; c. ... Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ... 1966 Airstream Overlander International Airstream is the name of a brand of recreational vehicle presently manufactured in Jackson Center, Ohio. ...

Water is also exchanged between the hydrosphere, lithosphere, atmosphere and biosphere in regular cycles. The oceans are large tanks, which store water, ensure thermal and climatic stability, as well as the transport of chemical elements thanks to large oceanic currents. Cycles are series of states or conditions that repeat themselves, usually after a regular or nearly regular period. ... An ocean current is any more or less permanent or continuous, directed movement of ocean water that flows in one of the Earths oceans. ...

For a better understanding of how the biosphere works, and various dysfunctions related to human activity, American scientists simulated the biosphere in a small-scale model, called Biosphere II. Biosphere 2 is a manmade closed ecological system in Oracle, Arizona built by Edward P. Bass, Space Biosphere Ventures and others. ...

The ecosystem concept

Main article: Ecosystem

The first principle of ecology is that each living organism has an ongoing and continual relationship with every other element that makes up its environment. An ecosystem can be defined as any situation where there is interaction between organisms and their environment. In ecology, the word ecosystem is an abbreviation of the term, ecological system. ... In ecology, the word ecosystem is an abbreviation of the term, ecological system. ...

The ecosystem is composed of two entities, the entirety of life, the biocoenosis and the medium that life exists in the biotope. Within the ecosystem, species are connected and dependent upon one another in the food chain, and exchange energy and matter between themselves and with their environment. A biocoenosis (alternatively, biocoenose or biocenose), termed by Karl Möbius in 1877, describes all the interacting organisms living together in a specific habitat (or biotope). ... A biotope is an area of uniform environmental (physical) conditions providing habitat(s) for a specific assemblage of plants and animals. ... Food chains and food webs or food networks describe the feeding relationships between species in a biotic community. ... Matter is commonly defined as the substance of which physical objects are composed. ...

The concept of an ecosystem can apply to units of variable size, such as a pond, a field, or a piece of deadwood. A unit of smaller size is called a microecosystem. For example, an ecosystem can be a stone and all the life under it. A mesoecosystem could be a forest, and a macroecosystem a whole ecoregion, with its drainage basin. A pond is a body of water smaller than a lake. ... Microecosystems can exist in surprisingly many locations which are precisely defined by critical environmental factors within small or tiny spaces. ... A forest is an area with a high density of trees (or, historically, a wooded function as carbon dioxide sinks, animal habitats, hydrologic flow modulators, and soil conservers, constituting one of the most important aspects of the Earths biosphere. ... An ecoregion is a relatively large area of land or water that contains a geographically distinct assemblage of natural communities. ... For the term related to television programmes, see watershed (television). ...

The main questions when studying an ecosystem are:

• Whether the colonization of a barren area could be carried out
• Investigation the ecosystem's dynamics and changes
• The methods of which an ecosystem interacts at local, regional and global scale
• Whether the current state is stable
• Investigating the value of an ecosystem and the ways and means that interaction of ecological systems provide benefit to humans, especially in the provision of healthy water?

Ecosystems are often classified by reference to the biotopes concerned. The following ecosystems may be defined:

• As continental ecosystems, such as forest ecosystems, meadow ecosystems such as steppes or savannas), or agro-ecosystems
• As ecosystems of inland waters, such as lentic ecosystems such as lakes or ponds; or lotic ecosystems such as rivers
• As oceanic ecosystems.

Another classification can be done by reference to its communities, such as in the case of an human ecosystem. A steppe in Western Kazakhstan in early spring In physical geography, a steppe (Russian степь or step and pronounced in English as step) is a plain without trees (apart from those near rivers and lakes); it is similar to a prairie, although a prairie is generally considered as being dominated by... Savanna is a grassland dotted with trees, and occurs in several types of biomes. ... Agroecology is the science of applying ecological concepts and principles to the design, development, and management of sustainable agricultural systems. ... A lake is a body of water surrounded by land. ... A pond is a body of water smaller than a lake. ... The Murray River in Australia. ... Human ecosystems are complex cybernetic systems that are increasingly being used by ecological anthropologists and other scholars to examine the human-ecological aspects of phenomena such as economics, socio-political organizations, ritual et cetera. ...

Dynamics and stability

Main articles: biogeochemistry, Homeostasis, Population dynamics

Ecological factors which can affect dynamic change in a population or species in a given ecology or environment are usually divided into two groups: abiotic and biotic. The field of biogeochemistry involves scientific study of the chemical, physical, geological, and biological processes and reactions that govern the composition of the natural environment (including the biosphere, the hydrosphere, the pedosphere, the atmosphere, and the lithosphere), and the cycles of matter and energy that transport the Earths chemical... Homeostasis is the property of an open system, especially living organisms, to regulate its internal environment to maintain a stable, constant condition, by means of multiple dynamic equilibrium adjustments, controlled by interrelated regulation mechanisms. ... Population dynamics is the study of marginal and long-term changes in the numbers, individual weights and age composition of individuals in one or several populations, and biological and environmental processes influencing those changes. ... In biology, a species is the basic unit of biodiversity. ...

Abiotic factors are geological, geographical, hydrological and climatological parameters. A biotope is an environmentally uniform region characterized by a particular set of abiotic ecological factors. Specific abiotic factors include: Ecohydrology is a sub-discipline of hydrology that focuses on ecological processes involved in the hydrological cycle. ...

• Water, which is at the same time an essential element to life and a milieu
• Air, which provides oxygen, nitrogen, and carbon dioxide to living species and allows the dissemination of pollen and spores
• Soil, at the same time source of nutriment and physical support
  • Soil pH, salinity, nitrogen and phosphorus content, ability to retain water, and density are all influential
• Temperature, which should not exceed certain extremes, even if tolerance to heat is significant for some species
• Light, which provides energy to the ecosystem through photosynthesis
• Natural disasters can also be considered abiotic

Biocenose, or community, is a group of populations of plants, animals, micro-organisms. Each population is the result of procreations between individuals of same species and cohabitation in a given place and for a given time. When a population consists of an insufficient number of individuals, that population is threatened with extinction; the extinction of a species can approach when all biocenoses composed of individuals of the species are in decline. In small populations, consanguinity (inbreeding) can result in reduced genetic diversity that can further weaken the biocenose. A girl in a swimming pool Water (from the Old English waeter; c. ... The Natural Environment comprises all living and non-living things that occur naturally on Earth. ... Layers of Atmosphere (NOAA) Earths atmosphere is a layer of gases surrounding the planet Earth and retained by the Earths gravity. ... SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomea purpurea), hollyhock (Sildalcea malviflora), lily (Lilium auratum), primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Soil is material capable of supporting plant life. ... The correct title of this article is pH. The initial letter is capitalized due to technical restrictions. ... Soil Salinity is a major environmental issue in Australia, chiefly affecting agricultural lands in many areas of W.A. (Western Australia) Much of central Australia was at one time a shallow inland sea. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of any wavelength. ... Leaf. ... A natural disaster is the consequence or effect of a hazardous event, occurring when human activities and a natural phenomenon (a physical event, such as a volcanic eruption, earthquake, landslide etc. ... Reproduction is the creation of one thing as a copy of, product of, or replacement for a similar thing, e. ... Cohabitation is an arrangement where two unrelated people live together, often as part of a sexual relationship. ... Inbreeding is breeding between close relatives. ... Genetic diversity is a characteristic of ecosystems and gene pools that describes an attribute which is commonly held to be advantageous for survival -- that there are many different versions of otherwise similar organisms. ...

Biotic ecological factors also influence biocenose viability; these factors are considered as either intraspecific and interspecific relations.

Intraspecific relations are those which are established between individuals of the same species, forming a population. They are relations of co-operation or competition, with division of the territory, and sometimes organization in hierarchical societies.

Interspecific relations—interactions between different species—are numerous, and usually described according to their beneficial, detrimental or neutral effect (for example, mutualism (relation ++) or competition (relation --). The most significant relation is the relation of predation (to eat or to be eaten), which leads to the essential concepts in ecology of food chains (for example, the grass is consumed by the herbivore, itself consumed by a carnivore, itself consumed by a carnivore of larger size). A high predator to prey ratio can have a negative influence on both the predator and prey biocenoses in that low availability of food and high death rate prior to sexual maturity can decrease (or prevent the increase of) populations of each, respectively. Selective hunting of species by humans which leads to population decline is one example of a high predator to prey ratio in action. Other interspecific relations include parasitism, infectious disease and competition for limiting resources, which can occur when two species share the same ecological niche.

The existing interactions between the various living beings go along with a permanent mixing of mineral and organic substances, absorbed by organisms for their growth, their maintenance and their reproduction, to be finally rejected as waste. These permanent recyclings of the elements (in particular carbon, oxygen and nitrogen) as well as the water are called biogeochemical cycles. They guarantee a durable stability of the biosphere (at least when unchecked human influence and extreme weather or geological phenomena are left aside). This self-regulation, supported by negative feedback controls, ensures the perenniality of the ecosystems. It is shown by the very stable concentrations of most elements of each compartment. This is referred to as homeostasis. The ecosystem also tends to evolve to a state of ideal balance, reached after a succession of events, the climax (for example a pond can become a peat bog). Co-operation refers to the practice of people or greater entities working in common with commonly agreed-upon goals and possibly methods, instead of working separately in competition. ... Competition is the act of striving against another force for the purpose of achieving dominance or attaining a reward or goal, or out of a biological imperative such as survival. ... Biological interactions result from the fact that organisms in an ecosystem interact with each other, in the natural world, no organism is an autonomous entity isolated from its surroundings. ... In biology, mutualism is an interaction between two species in which both species derive benefit. ... Competition is the act of striving against another force for the purpose of achieving dominance or attaining a reward or goal, or out of a biological imperative such as survival. ... ŒœáħŐųŁġĖĞɮʙ[[]] It has been suggested that this article or section be merged with predation. ... Food chains and food webs or food networks describe the feeding relationships between species in a biotic community. ... Parasitism is an interaction between two organisms, in which one organism (the parasite) benefits and the other (the host) is harmed. ... In medicine, infectious disease or communicable disease is disease caused by a biological agent such as by a virus, bacterium or parasite. ... In ecology, a niche is a term describing the relational position of a species or population in an ecosystem. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... A girl in a swimming pool Water (from the Old English waeter; c. ... In ecology, a biogeochemical cycle is a circuit where a nutrient moves back and forth between both biotic and abiotic components of ecosystems. ... The cost of extreme weather is rising rapidly and could reach 350 billion U.S. 2001 dollars per year by 2025. ... Feedback is (generally) information about actions. ... Homeostasis is the property of an open system, especially living organisms, to regulate its internal environment to maintain a stable, constant condition, by means of multiple dynamic equilibrium adjustments, controlled by interrelated regulation mechanisms. ... Secondary succession: trees are colonizing uncultivated fields and meadows Ecological succession, a fundamental concept in ecology, is the process by which a natural community moves from a simpler level of organisation to a more complex community. ... The term climax community is an outdated ecological term for a community of plants and animals which is the result of succession, where a biological system, a community, or a soil has reached a steady state. ... Virgin boreal acid bogs at Browns Lake Bog, Ohio A bog is a wetland type that accumulates peat, a deposit of dead plant material. ...

Spatial relationships and subdivisions of land

Main articles: Biome, ecozone

Ecosystems are not isolated from each other, but are interrelated. For example, water may circulate between ecosystems by the means of a river or ocean current. Water itself, as a liquid medium, even defines ecosystems. Some species, such as salmon or freshwater eels move between marine systems and fresh-water systems. These relationships between the ecosystems lead to the concept of a biome. In ecology, a biome is a major regional group of distinctive plant and animal communities best adapted to the regions physical natural environment, latitude, altitude and terrain factors. ... Ecozone is a classification system of the world first proposed by Miklos Udvardy under the name biogeographical realms for conservation purposes. ... A girl in a swimming pool Water (from the Old English waeter; c. ... The Murray River in Australia. ... An ocean current is any more or less permanent or continuous, directed movement of ocean water that flows in one of the Earths oceans. ... The Chinook or King Salmon is the largest salmon in North America and can grow up to 58 long and 125 pounds. ... Suborders Anguilloidei Nemichthyoidei Congroidei Synaphobranchoidei See text for families. ...

A biome is a homogeneous ecological formation that exists over a vast region, such as tundra or steppes. The biosphere comprises all of the Earth's biomes -- the entirety of places where life is possible -- from the highest mountains to the depths of the oceans. In ecology, a biome is a major regional group of distinctive plant and animal communities best adapted to the regions physical natural environment, latitude, altitude and terrain factors. ... In physical geography, tundra is an area where the tree growth is hindered by low temperatures and short growing seasons. ... A steppe in Western Kazakhstan in early spring In physical geography, a steppe (Russian степь or step and pronounced in English as step) is a plain without trees (apart from those near rivers and lakes); it is similar to a prairie, although a prairie is generally considered as being dominated by... The biosphere is that part of a planets outer shell — including air, land, surface rocks and water — within which life occurs, and which biotic processes in turn alter or transform. ...

Biomes correspond rather well to subdivisions distributed along the latitudes, from the equator towards the poles, with differences based on to the physical environment (for example, oceans or mountain ranges) and to the climate. Their variation is generally related to the distribution of species according to their ability to tolerate temperature and/or dryness. For example, one may find photosynthetic algae only in the photic part of the ocean (where light penetrates), while conifers are mostly found in mountains. The equator is an imaginary circle drawn around a planet (or other astronomical object) at a distance halfway between the poles. ... Leaf. ... A seaweed (Laurencia) up close: the branches are multicellular and only about 1 mm thick. ... Orders & Families Cordaitales † Pinales   Pinaceae - Pine family   Araucariaceae - Araucaria family   Podocarpaceae - Yellow-wood family   Sciadopityaceae - Umbrella-pine family   Cupressaceae - Cypress family   Cephalotaxaceae - Plum-yew family   Taxaceae - Yew family Vojnovskyales † Voltziales † The conifers, division Pinophyta, are one of 13 or 14 division level taxa within the Kingdom Plantae. ...

Though this is a simplification of more complicated scheme, latitude and altitude approximate a good representation of the distribution of biodiversity within the biosphere. Very generally, the richness of biodiversity (as well for animal than plant species) is decreasing most rapidly near the equator (as in Brazil) and less rapidly as one approaches the poles. Latitude, usually denoted symbolically by the Greek letter φ, gives the location of a place on Earth north or south of the Equator. ... ... Rainforests are the most biodiverse ecosystems on earth Biodiversity or biological diversity is the diversity of life. ... The equator is an imaginary circle drawn around a planet (or other astronomical object) at a distance halfway between the poles. ...

The biosphere may also be divided into ecozone, which are very well defined today and primarily follow the continental borders. The ecozones are themselves divided into ecoregions, though there is not agreement on their limits. Ecozone is a classification system of the world first proposed by Miklos Udvardy under the name biogeographical realms for conservation purposes. ... An ecoregion is a relatively large area of land or water that contains a geographically distinct assemblage of natural communities. ...

Ecosystem productivity

In an ecosystem, the connections between species are generally related to food and their role in the food chain. There are three categories of organisms: Food chains and food webs or food networks describe the feeding relationships between species in a biotic community. ...

• Producers -- plants which are capable of photosynthesis
• Consumers -- animals, which can be primary consumers (herbivorous), or secondary or tertiary consumers (carnivorous).
• Decomposers -- bacteria, mushrooms which degrade organic matter of all categories, and restore minerals to the environment.

These relations form sequences, in which each individual consumes the preceding one and is consumed by the one following, in what are called food chains or food network. In a food network, there will be fewer organisms at each level as one follows the links of the network up the chain. Leaf. ... In zoology, an herbivore is an animal that is adapted to eat primarily plants (rather than meat). ... This article deals with meat-eating animals. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Basidiocarps (mushrooms) of the fungus Leucocoprinus sp. ... Food chains and food webs or food networks describe the feeding relationships between species in a biotic community. ...

These concepts lead to the idea of biomass (the total living matter in a given place), of primary productivity (the increase in the mass of plants during a given time) and of secondary productivity (the living matter produced by consumers and the decomposers in a given time). Biomass is organic non-fossil material, collectively. ... Primary productivity is the amount of light energy converted to chemical energy in a given amount of time. ...

These two last ideas are key, since they make it possible to evaluate the load capacity -- the number of organisms which can be supported by a given ecosystem. In any food network, the energy contained in the level of the producers is not completely transferred to the consumers. Thus, from an energy point of view, it is more efficient for humans to be primary consumers (to get nourishment from grains and vegetables) than as secondary consumers (from herbivores such as beef and veal), and more still than as a tertiary consumer (from eating carnivores).

The productivity of ecosystems is sometimes estimated by comparing three types of land-based ecosystems and the total of aquatic ecosystems:

• The forests (1/3 of the Earth's land area) contain dense biomasses and are very productive. The total production of the world's forests corresponds to half of the primary production.
• Savannas, meadows, and marshes (1/3 of the Earth's land area) contain less dense biomasses, but are productive. These ecosystems represent the major part of what humans depend on for food.
• Extreme ecosystems in the areas with more extreme climates -- deserts and semi-deserts, tundra, alpine meadows, and steppes -- (1/3 of the Earth's land area) have very sparse biomasses and low productivity
• Finally, the marine and fresh water ecosystems (3/4 of Earth's surface) contain very sparse biomasses (apart from the coastal zones).

Humanity's actions over the last few centuries have seriously reduced the amount of the Earth covered by forests (deforestation), and have increased agro-ecosystems (agriculture). In recent decades, an increase in the areas occupied by extreme ecosystems has occurred (desertification). Deforestation is the conversion of forested areas to non-forested. ... Ship stranded by the retreat of the Aral Sea Desertification is the degradation of land in arid, semi arid and dry sub-humid areas resulting from various factors including climatic variations and human activities. ...

Ecological crisis

Generally, an ecological crisis is what occurs when the environment of a species or a population evolves in a way unfavourable to that species survival. An ecological crisis occurs when the environment of a species or a population changes in a way that destablizes its continued survival. ...

It may be that the environment quality degrades compared to the species needs, after a change in an abiotic ecological factor (for example, an increase of temperature, less significant rainfalls).
It may be that the environment becomes unfavourable for the survival of a species (or a population) due to an increased pressure of predation (for example overfishing).
Lastly, it may be that the situation becomes unfavourable to the quality of life of the species (or the population) due to a rise in the number of individuals (overpopulation). Ecological factors which can affect dynamic change in a population or species in a given ecology or environment are usually divided into two groups: abiotic and biotic. ... It has been suggested that this article or section be merged with predator. ... Overpopulation occurs when the population of a living species exceeds the carrying capacity of its ecological niche. ...

Ecological crises may be more or less brutal (occurring within a few months or taking as long as a few million years). They can also be of natural or anthropic origin. They may relate to one unique species or to many species (see the article on Extinction event). An extinction event (also extinction-level event, ELE) occurs when a large number of species die out in a relatively short period of time. ...

Lastly, an ecological crisis may be local (as an oil spill) or global (a rise in the sea level due to global warming). Volunteers cleaning up the aftermath of the Prestige oil spill An oil spill is the intentional or unintentional release of oil (generally, petroleum) into the natural environment as a result of human activity. ... Global mean surface temperatures 1856 to 2005 Mean temperature anomalies during the period 1995 to 2004 with respect to the average temperatures from 1940 to 1980 Global warming is a term used to describe the trend of increases in the average temperature of the Earths atmosphere and oceans that...

According to its degree of endemism, a local crisis will have more or less significant consequences, from the death of many individuals to the total extinction of a species. Whatever its origin, disappearance of one or several species often will involve a rupture in the food chain, further impacting the survival of other species. Food chains and food webs or food networks describe the feeding relationships between species in a biotic community. ...

In the case of a global crisis, the consequences can be much more significant; some extinction events showed the disappearance of more than 90% of existing species at that time. However, it should be noted that the disappearance of certain species, such as the dinosaurs, by freeing an ecological niche, allowed the development and the diversification of the mammals. An ecological crisis thus paradoxically favored biodiversity.

Sometimes, an ecological crisis can be a specific and reversible phenomenon at the ecosystem scale. But more generally, the crises impact will last. Indeed, it rather is a connected series of events, that occur till a final point. From this stage, no return to the previous stable state is possible, and a new stable state will be set up gradually (see homeorhesy).

Lastly, if an ecological crisis can cause extinction, it can also more simply reduce the quality of life of the remaining individuals. Thus, even if the diversity of the human population is sometimes considered threatened (see in particular indigenous people), few people envision human disappearance at short span. However, epidemic diseases, famines, impact on health of reduction of air quality, food crises, reduction of living space, accumulation of toxic or non degradable wastes, threats on keystone species (great apes, panda, whales) are also factors influencing the well-being of people. Indigenous peoples are: Peoples living in an area prior to colonization by a state Peoples living in an area within a nation-state, prior to the formation of a nation-state, but who do not identify with the dominant nation. ... A famine is a phenomenon in which a large percentage of the population of a region or country are so undernourished that death by starvation becomes increasingly common. ... The Air Quality Index (AQI) is a standardized index of the air quality in a given location, given in parts per billion. ... Many food crises have occurred in the world today. ... A keystone predator may prevent a particular prey species from overrunning an ecosystem. ... The well-being or quality of life of a population is an important concern in economics and political science. ...

During the past decades, this increasing responsibility of humanity in some ecological crises has been clearly observed. Due to the increases in technology and a rapidly increasing population, humans have more influence on their own environment than any other ecosystem engineer. An ecosystem engineer is any organism that modifies its own ecosystem. ...

Some usually quoted examples as ecological crises are:

• Permian-Triassic extinction event 250 million of years ago
• Cretaceous-Tertiary extinction event 65 million years ago
• Global warming related to the Greenhouse effect. Warming could involve flooding of the Asian deltas (see also ecorefugees), multiplication of extreme weather phenomena and changes in the nature and quantity of the food resources (see Global warming and agriculture). See also international Kyoto Protocol.
• Ozone layer hole issue
• Deforestation and desertification, with disappearance of many species.
• The nuclear meltdown at Chernobyl in 1986 caused the death of many people and animals from cancer, and caused mutations in a large number of animals and people. The area around the plant is now abandoned because of the large amount of radiation generated by the meltdown.

The Permian-Triassic extinction event, labeled End P here, is the most significant extinction event in this plot for marine fossiliferous genera. ... Badlands near Drumheller, Alberta where erosion has exposed the KT boundary. ... Global mean surface temperatures 1856 to 2005 Mean temperature anomalies during the period 1995 to 2004 with respect to the average temperatures from 1940 to 1980 Global warming is a term used to describe the trend of increases in the average temperature of the Earths atmosphere and oceans that... The greenhouse effect, first discovered by Joseph Fourier in 1824, and first investigated quantitatively by Svante Arrhenius in 1896, is the process by which an atmosphere warms a planet. ... The cost of extreme weather is rising rapidly and could reach 350 billion U.S. 2001 dollars per year by 2025. ... As global warming causes climate change, the issue of effects of global warming on agriculture due to the change in weather conditions is often invoked in arguments on the course of action involving prediction of climate events. ... Kyoto Protocol Opened for signature December 11, 1997 in Kyoto, Japan Entered into force February 16, 2005. ... The ozone layer, or ozonosphere layer (rarely used term), is that part of the Earths atmosphere which contains relatively high concentrations of ozone (O3). ... Deforestation is the conversion of forested areas to non-forested. ... Ship stranded by the retreat of the Aral Sea Desertification is the degradation of land in arid, semi arid and dry sub-humid areas resulting from various factors including climatic variations and human activities. ... Core of a nuclear reactor A nuclear power station. ... Chernobyl area. ... 1986 (MCMLXXXVI) was a common year starting on Wednesday of the Gregorian calendar. ... When normal cells are damaged beyond repair, they are eliminated by apoptosis. ...

See also

Wikibooks has more about this subject:

Ecology

• ELDIS, a database on ecological aspects of economical development.
• Ecology movement
• Deep Ecology
• List of ecologists
• List of ecology topics
• List of biology topics
• Important publications in ecology

Image File history File links Wikibooks-logo-en. ... Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a sister project to Wikipedia and is part of the Wikimedia Foundation, begun on July 10, 2003. ... ELDIS is a database and email service of information sources on economic development and the environment. ... The global ecology movement is one of several new social movements that emerged at the end of the sixties; as a values-driven social movement, it should be distinguished from the pre-existing science of ecology. ... Deep ecology is a recent philosophy or ecosophy based on a shift away from the anthropocentric bias of established environmental and green movements. ... This is a list of ecologists who have articles, in alphabetical order by surname. ... This page aims to list articles on Wikipedia that are related to ecology. ... This page aims to list articles related to biology. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Biology is a branch of science, dealing with the study of life. ... Anatomical drawing of the human muscles from the Encyclopédie. ... Astrobiology is an interdisciplinary field, combining aspects of astronomy, biology and geology, which is focused primarily on the study of the origin, distribution and evolution of life. ... Biochemistry is the study of the chemistry of life, a bridge between biology and chemistry that studies how complex chemical reactions give rise to life. ... Making sense of the huge amounts of DNA data (pictured) produced by gene sequencing projects is just one of the tasks faced by bioinformatics. ... Botany is the scientific study of plantlife. ... Cell biology (also called cellular biology or cytology, from the Greek kytos, container) is an academic discipline which studies cells. ... Developmental biology is the study of the process by which organisms grow and develop. ... Evolutionary biology is a subfield of biology concerned with the origin and descent of species, as well as their change over time, i. ... Genetics (from the Greek genno γεννώ= give birth) is the science of genes, heredity, and the variation of organisms. ... Genomics is the study of an organisms genome and the use of the genes. ... Marine biology is the scientific study of the plants, animals, and other organisms that live in the ocean. ... Human biology is an academic field of biology which focuses on humans; it is closely related to medicine, primate biology, and a number of other fields. ... Microbiology is the study of microorganisms, which are unicellular or cell-cluster microscopic organisms. ... Molecular biology is the study of biology at a molecular level. ... Pre-Cambrian stromatolites in the Siyeh Formation, Glacier National Park. ... A paleontologist carefully chips rock from a column of dinosaur vertebrae. ... Parasitology is the study of parasites, their hosts, and the relationship between them. ... Physiology (in Greek physis = nature and logos = word) is the study of the mechanical, physical, and biochemical functions of living organisms. ... Taxonomy (from Greek verb tassein = to classify and nomos = law, science, cf economy) may refer to: the science of classifying living things (see alpha taxonomy) a classification Initially, taxonomy was only the science of classifying living organisms, but later the word was applied in a wider sense, and may also... Zoology (Greek zoon = animal and logos = word) is the biological discipline which involves the study of animals. ... The lunar farside as seen from Apollo 11 Natural science is the study of the physical, nonhuman aspects of the Earth and the universe around us. ... Lunar astronomy: the large crater is Daedalus, photographed by the crew of Apollo 11 as they circled the Moon in 1969. ... Biology is a branch of science, dealing with the study of life. ... Multicolored chemicals are frequent hallmarks of chemistry. ... ... Physical science is an encompassing term for the branches of natural science, and science (generally), that study non-living systems, in contrast to the biological sciences. ... A Superconductor demonstrating the Meissner Effect. ...