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78 Cards in this Set
- Front
- Back
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Abiotic factor?
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a non living physical factor that may influence an organism or ecosystem; for example temperature, sunlight, pH, salinity, precipitation
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biochemical oxygen demand (BOD)
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a measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity
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Biodegradable
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capable of being broken down by natural biological processes; for example, the activities of decomposer organisms.
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Biodiversity
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the amount of biological or living diversity per unit area. it includes the concepts of species diversity, habitat diversity and genetic diversity
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Biomass
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the mass of organic material in organisms or ecosystems, usually per unit area. Sometimes the term dry weight biomass is used where mass is measured after the removal of water. Water is not organic material and inorganic material is usually relatively insignificant in terms of mass
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Biome
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a collection of ecosystems sharing similar climatic conditions; for example, tundra, tropical rainforest, desert.
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Biosphere
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That part of the earth inhabitated by organisms, that is, the narrow zone (a few kilometers in thickness) in which plants and animals exist. It exends from the upper part of the atmosphere (where birds, insects and wind blown pollen may be found) down to the deeper part of the earth's crust to which living organisms venture.
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Biotic factor
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A living biological factor that may influence an organism or ecosystem; for example, predation, parasitism, disease, competition
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Carrying capacity
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the maximum number of a species or 'load' that can be sustainably suppoted by a given environment
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climax community
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a community of organisms that is more or less stable and that is in equilibrium with natural environmental conditions such as climate; the end oint of ecological succession.
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community
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a group of populations living and interacting with each other in a common habitat
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competition
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a common demand by two or more organisms upon a limited supply of a resource; for example food, water, light, space, mates, nesting sites. it may be intraspecific or interspecific
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correlation
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a measure of the associatio between two variables. if two variables tend to move up or down together they are said to be positively correlated. if they tend to move in opposite directions they are said to be negatively correlated
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crude birth rate
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the number of births per thousand individuals in a population per year
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crude death rate
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the number of deaths per thousand individuals in a population per year
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demographic transition
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a general model describing the changing levels of fertility and moratlity in a human population over time. it was developed with reference to thetransition experienced as developed countries passed through the process of industrialization and urbanization
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diversity
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a generic term for hetereogeneity. the scientific meaning of diversity becomes clear from the context in which it is used; it may refer to hetereogeneity of specise or habitat or to genetic hetereogeneity.
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diversity, genetic
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the range of genetic material present in a gene pool or population of a species
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diversity, habitat
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the range of different habitats or number of ecological niches per unit area in an ecosystem, community or biome. conservation of habitat diversity usually leads to the conservation of species and genetic diversity
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diversity index
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a numerical measure of species diversity that is derived from both the number of species (variety) and their proportional abundance
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diversity, species
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the variety of species per unit area. this includes both the number of species present and their relative abundance
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doubling time
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the number of years it would take a population to double its size at its current growth rate. a natural increase rate of 1% will enable a human population to double in 70 years. Other doubling times can then be calculated proportionately, that is, the doubling time for any human population is equal to 70 divided by the natural increase rate
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ecological footprint
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the area of land and water required to support a defined human population at a given standard of living. the measure takes account of and the assimilation of all wastes.
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entropy
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a measure of the amount of disorder, chaos, or randomness in a system; the greater the disorder the higher the level of entropy
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Environmental Impact Assessment (EIA)
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a method of detailed survey required, in many countries, before a major development. ideally it should be independant of, but paid for, by the the developer. such a survey should include a baseline study to measure environmental conditions before development commences, and to identify areas and species of conservation importance. the report roduced is known as an environmental impact statement (EIS) or environmental management review in some coutnries. the monitoring should continue for some time after the development.
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Equilibrium
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a state of balance among the components of a system
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Eutrophication
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the natural or artificial enrichment of a body of water, particularly with respect to nitrates and phosphates, that results in depletion of the oxygen content of the water. Eutrophication is accelerated by human activities that add detergents, sewage or agricultural fertilizers to bodies of water.
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evolution
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the cumulative gradual change in the genetic characteristics of successive generations of a species or race of an organism, ultimately giving rise to species or races different from the common ancestor. evolution reflects changes in the genetic composition of a population over time.
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feedback
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the return of parts of the output from a system as input, so as to affect succeeding outputs
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feedback, negative
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feedback that tends to damp down, neutralize or counteract any deviation from an equilibrium and promotes stability
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feedback, positive
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feedback that amplifies or increases change; it leads to exponential deviation away from an equilibrium
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fertility
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in the context of human populations, this refers to the potential for reproduction exhibited in a poulation. it may be measured as fertility rate, which is the number of births per thousand women of child bearing age. alternatively it may be measured as total fertility which is simply the average number of children a women has in her lifetime
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Gaia
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the Gaia hypothesis compares the earth to a living organism in which feedback mechanisms maintain equilibrium
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global warming
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an increase in the average temperature of the earth's atmosphere
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GNP
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the gross national product, the current value of all goods and services produced in a country per year
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Greenhouse gases
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those atmospheric gases which absorb infrared radiation, causing world temperatures to be warmer than they would otherwise be. this process is sometimes known as radiation trapping. the natural greenhouse effect is caused mainly by water and carbon dioxide. human activities have led to an increase in the levels of carbon dioxide, methane and nitrous oxide in the atmosphere, and there are fears this may lead to global warming.
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habitat
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the environment in which a species normally lives
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halogenated organic gasses
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usually known as halocarbons and first identified as depleting the ozone layer in the stratosphere. now known to be potent greenhouse gases. the most well known are chlorofurocarbons (CFCs)
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isolation
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the process in which two populations become seperated by geograhical, behavioral, genetic or reproductive factors. if gene flow between the two subpopulations is prevented, new species may evolve.
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k strategist
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specise that usually concentrate their reproductive investment in a small number of offspring, thus increasing their survival rate and adapting them for living in long term climax communities
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latitude
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the angular distanec from the equator as measured from the center of the earth
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LEDC
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less economically developed country: a coutnry with low to moderate industrialization and low to moderate GNP per capita
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MEDC
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more economically developed country: a highly industrialized country with high average GNP per capita
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Model
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a simplified description designed to show the structure or workings of an object, system or concept
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Mutualism
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a relationship between individuals of two or more species in which all benefit and none suffer
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Natural capital
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a term sometimes used by economist for natural resources that if appropriately managed can produce a natural income of goods and services.
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natural capital, non renewable
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natural resources that cannot be replenished within a timescale of the same order as that which they are taken from the environment and used; for examle, fossil fuels.
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natural capital, renewable
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natural resources that have a sustainable yield or harvest equal to or less than their natural productivity; for exampe, food crops, timber.
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natural capital, replenishable
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non living natural resources that depend on the energy of the sun for their replenishment, for example groundwater.
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natural increase, rate of
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the form in which human population growth rates are usually expressed.
crude birth rate - crude death rate ----------------------------------------- 10 (inward and outward migration is ignored) |
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Niche
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a species share of a habitat and the resouces in it. an organism's ecological niche depends not only on where it lives but also on what it does
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Parasitism
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a relationship between two species in which one specise (the parasite) lives in or on another (the host) gaining all or much of it's food from it
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plate tectonics
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the movement of the eight major and several minor internally rigid plates of the earth's lithosphere in relation to each toher and to the partially mobile asthenosphere below.
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pollution
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the addition to an environment of a substance or an agent by human activity at a rate greater than that at which it can be rendered harmless by the environment and which has an apreciable effect on the organisms within it.
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pollution, non point source
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the release of pollutants from numerous, widely dispersed origins, for example, gases from the exhaust systems of vehicles
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pollution, oint source
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the release of pollutants from a single, clearly identifiable site; for example, a factory chimney or the waste disposal pie of a factory into a river.
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population
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a group of organisms of the same species living in the same area at the same time and which are capable of interbreeding.
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productivity, gross (GP
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the total gain in energy or biomass per unit area per unit time which could be through photosynthesis in primary producers or absorption in consumers
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productivity, gross primary (GPP)
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the total gain in energy or biomass per unit area per unit time fixed by photosynthesis in green plants
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productivity, gross secondary (GSP)
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the total gain by consumers in energy or biomass per unti area per unit time through absorption
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R Strategist
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Species that tend to spread their reproductive investment among a large number of offspring so that they are well adapted to colonize new habitats rapidly and make opportunistic use of their short lived resouces
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Sere
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The set of communities that succeed one another over the course of succession at a given location?
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Smog
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The term now used for any haziness in the atmosphere caused by air pollutants. Photochemical smog is produced through the effects of ultraviolet light on the products of internal combustion engines. It may contain ozone and is damaging to the human respiratory system and eyes
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Society
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An arbitrary group of individuals who share some common characteristic such as geographical location, cultural background, historical timeframe, religious perspective, value system, and so on.
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Soil
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A mixture of mineral particles and organic material that covers the land, and in which terrestrial plants grow
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Soil profile
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A vertical section through a soil, from the surface down to the parent material, revealing the soil layers or horizons.
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Speciation
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The process through which new species form. See also evolution
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Species
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A group of organisms that interbreed and produce fertile offspring.
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Stable Equilibrium
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The condition of a system in which there is a tendency for it to return to a previous equilibrium condition following disturbance.
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Steady-State Equilibirum
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The condition of an open system in which there are no changes over the longer term, but in which there may be oscillations in the very short term. There are continuing inputs and outputs of matter and energy, but the system as a whole remains in a more or less constant state (for example, a climax ecosystem)
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Succession
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The orderly process of change over tine in a community. Changes in the community of organisms frequently causes changes in the physical environment that allow another community to become established and replace the former through competition. Often, but not inevitably, the later communities in such a sequence or sere are more complex than those that appear earlier
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Sustainability
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Use of global resources at a rate that allows natural regeneration and minimizes damage to the environment. For example, a system of harvesting renewable resources at a rate that will be replaced by natural growth by be considered to demonstrate sustainability
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System
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An assemblage of parts and the relationships between them, which together constitute an entity or whole
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System, Closed
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A system in which energy, but not matter, is exchanged with its surroundings
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System, Isolated
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A system that exchanges neither matter nor energy with its surroundings.
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System, Open
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A system in which both matter and energy are exchanged with its surroundings (for example, natural ecosystems)
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Trophic level
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The position that an organism occupies in a food chain, or a group of organisms in a community that occupy the same position in food chains.
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Zonation
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The arrangement or patterning of plant communities or ecosystems into parallel or sub parallel bands in response to change, over a distance, in some environmental factor. The main biomes display zonation in relation to latitude on a mountain, or around the edge of a pond in relation to the soil moisture.
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