All Key terms

environmental value system

world view or paradigm that shapes the way an individual or group of individuals perceive and evaluate environmental issues- influenced by cultural, religious, economic and socio-political contexts

abiotic factor

a non-living, physical factor that may influence and organism or ecosystem

environmental value system

world view or paradigm that shapes the way an individual or group of individuals perceive and evaluate environmental issues- influenced by cultural, religious, economic and socio-political contexts

abiotic factor

a non-living, physical factor that may influence and organism or ecosystem

biochemical oxygen demand (BOD)

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

biodegradable

capable of being broken down by natural biological processes

biodiversity

the amount of biological or living diversity per unit area- includes species diversity, habitat diversity and genetic diversity

biomass

the mass of organic material in organisms or ecosystems, usually per unit area

dry weight biomass

biomass after the removal of water weight

biome

a collection of ecosystems sharing similar climatic conditions

biosphere

the part of the Earth inhabited by organisms

biotic factor

a living biological factor that my influence an organism or ecosystem

carrying capacity

the maximum number of a species that can be sustainably supported by a given environment

climax community

a community of organisms that is more or less stable and in equilibrium with natural environmental conditions; the end point of ecological succession

community

a group of populations living and interacting within a common habitat

competition

a common demand by two or more organisms for a limited resource- intra or interspecific (same of different species)

crude birth rate

number of births per thousand individuals in a population per year

crude death rate

number of deaths per thousand individuals in a population per year

demographic transition

a general model describing the changing levels of fertility and mortality in a human population over time

diversity index

a numerical measure of species diversity that is derived from the number of species and their proportional abundance

doubling time

number of years it would take a population to double in size at its current growth rate. calculated by 70/ natural increase rate

ecological footprint

the area of land and water required to sustainably provide all resources at the rate which they are being consumed by a given population

ecosystem

a community of interdependent organisms and the physical environment they inhabit

entropy

a measure of the amount of disorder, chaos or randomness in an ecosystem; the greater the disorder, the higher the level of entropy

environmental impact assessment

a method of survey required, in many countries, before a major development- should be independent but paid for by the developer, include a baseline study to determine environmental issues and identify areas or species for specific focus and monitoring should continue for some time after the development

equilibrium

a state of balance among the components of a system

eutrophication

the natural or artificial enrichment of a body of water particularly with respect to nitrates and phosphates resulting in oxygen depletion in the water

evolution

the cumulative, gradual change in the genetic characteristics of successive generations of a species race or organism giving rise to species or races different to the ancestors

feedback

the return of part of the output from a system as input

albedo

the proportion of solar radiation that is reflected by a particular boy or surface

negative feedback

feedback that neutralises or counteracts deviance from equilibrium, promoting stability

positive feedback

feedback that amplifies or increases change, leading to exponential deviation from equilibrium

Gaia

a hypothesis proposed by James Lovelock that suggests that the Earth is a living organism in which feedback mechanisms maintain equilibrium

GNP

gross natural product, the current value of all goods and services produced in a country per year

habitat

the environment in which a species normally lives

halogenated organic gases

usually known as halocarbons and first identified s depleting the stratospheric ozone- now known to be a potent greenhouse gas eg: CFCs

isolation

the process by which two populations become separated by geographical, behavioural, genetic or reproductive factors. if the gene flow between the two subpopulations is separated then new species may form

k-strategist

species 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

model

a simplified description designed to show the structure or workings of a system, object or concept

mutualism

a relationship between individuals of two or more species in which all benefit and none suffer

natural capital

natural resources that can produce natural income

non-renewable

cannot be replenished within a timescale of the same order as that at which they are being taken from the environment and used eg: fossil fuels

renewable

having a sustainable yield/ harvest equal to or less than their natural productivity eg: timber

replenishable natural capital

non-living natural resources that depend on the energy of the sun for their replenishment eg: groundwater

natural increase rate (population)

the form in which human population growth rates are usually expressed- migration and immigration are ignored

niche

a species role in a habitat- it’s share of the resources, depends on where it lives and what it does

parasitism

a relationship between two species in which one species lives in or on another and takes much or all of its food

pollution

the addition to an environment of a substance or agent by human activity at a rate greater than can be rendered harmless to the environment and has an appreciable effect on the organisms in it

population

a group of organisms of the same species living in the same area at the same time and are capable of interbreeding

gross productivity

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

gross primary productivity

total gain in energy or biomass per unit area per unit time fixed by photosynthesis in green plants. crude birth rate- crude death rate

gross secondary productivity

the total gain in energy or biomass by consumers per unit area per unit time by consumers

net productivity

the gain in energy or biomass per unit area per unit time remaining after respitatory losses

net primary productivity

the gain in biomass or energy by producers per unit area per unit time after allowing for respiratory losses- the energy that is potentially available to consumers

net secondary productivity

the gain in biomass or energy by consumers per unit area per unit time after allowing for respiratory losses

r-strategist

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 short-lived resources

sere

the set of communities that succeed one another over the course of succession at a given location

smog

haziness in the atmosphere caused by pollutants

photochemical smog

smog produced through the effect of ultraviolet light on the products of internal combustion engines- damaging to the human respiratory system and eyes

society

an arbitrary group of individuals who share some common characteristic eg: geographical location, cultural background, religious perspective

soil

a mixture of mineral particles and organic material that covers the land and in which terrestrial plants grow

soil profile

a vertical section through soil, from the surface to the parent material revealing the horizons

speciation

the process through which new species form

species

a group of organisms that interbreed and produce fertile offspring

stable equilibrium

the condition of an ecosystem in which there is a tendency for it to return to its previous equilibrium condition following a disturbance

steady-state equilibrium

the condition of an open system in which there are no changes in the long term but there may be oscillations in the short term eg: a climax ecosystem

system

a set of inter-related parts working together to make a complex whole

closed system

a system in which energy but not matter is exchanged with its surroundings

isolated system

a system that exchanges neither matter nor energy with its surroundings

open system

a system that exchanges both matter and energy with its surroundings eg: natural ecosystems

transfer

when energy or matter flows and changes location but does not change state

transformation

when energy or matter flows and changes its state

tipping point

the critical threshold when even a small change can have dramatic effects

trophic level

the position that an organism occupies in a food chain, or a group of organisms in a community that occupy the same positions in a food chain

zonation

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

first law of thermodynamics

conservation of energy- energy in an isolated system can be transformed but cannot be created or destroyed

second law of thermodynamics

an increase in entropy arising from energy transformations reduces the energy available to do work

fundamental niche

the full range of conditions and resources in which a species could survive and reproduce

realised niche

the actual conditions and resources which a species exists due to biotic factors eg: predation

limiting factors

factors which slow down population growth as it reaches carrying capacity

population dynamics

the study of factors which change population size

turbidity

the cloudiness of a fresh body of water

biodiversity hotspot

an area of high biodiversity that is under threat from human activity

conservation biology

the sustainable use and management of natural resources

preservation biology

attempts to exclude human activity in areas where humans have not yet encroached

water budget

quantitative estimate of the amounts of water in in storages and flows of the water cycle

fishery

a place where fish are captured in some way- either in aquaculture or in the wild

aquaculture

the farming of aquatic organisms in both coastal and inland areas involving interventions in the rearing process to enhance production

adaptive capacity

ability or potential of a system to respond successfully to climate change and variability- includes adjustments in behaviors, resources and technologies