IB ESS Terms

the factors (abiotic or biotic) in an ecosystem which put pressure on an organism's survival and increase competition (whether inter-species or intra-species)

a combination of the species diversity, genetic diversity and habitat diversity of an ecosystem

the differences, either physical or genetic, between individuals of a species

a measure of diversity between similar ecosystems

the number of species (richness) and their relative proportions (evenness) in a community

the range of genetic material present in a gene pool or population of a species

the small differences which may occur in an organism as a result of reproduction - these small changes may add up to create variation

an area of high biodiversity (which is under threat from human activities)

the species which only occur in one specific area

the gradual change in populations of a species over time - often caused by geographical isolations, resulting in new species

the process by which a species may adapt to environmental pressures through natural selection of favourable variation - caused by random genetic mutations - over thousands of generations

survival of the fittest - only the best suited organisms will be able to compete (due to environmental pressures) and so survive long enough to reproduce - their favourable traits are then passed on to new generations

the separation of populations of a single species - often leads to speciation if populations cannot interbreed for a very long time

e.g. a mountain, ocean or separation of lakes

a connection between land masses - often as a result of lowering sea levels e.g. the Bering Straits

the movement of the tectonic plates by around 1cm a year causing the change in shape and location of continents

the Earth's crust - the rocky part of Earth

the land mass made up of Africa, New Zealand, Australia and South America, India, Arabia and Antarctica millions of years ago - separated millions of years ago

the natural rate of extinction of species - around 1 species per million species per year

the complete loss of a species from Earth - no more individuals of that species exist

an extinction rate far greater than background extinction rate

the 6th mass extinction occurring for the last 10,000 years, however, much faster in the last 100 years - generally agreed to be as a result of human activity

the species (generally plant or animal) which are able to survive the environments we create e.g. urban rats, domesticated animals

a report produced by the Worldwide Fund for Nature (WWF) creates on the state of the world's ecosystems

the act of preserving nature - attempting to save habitats, species and biodiversity in general

the proportion of living species which are found in tropical rainforests

approx. 100 species per million species per year

creates stability and resilience to change in an ecosystem - there are many pathways for energy flow

environmental conditions that limit the growth, abundance, or distribution of an organism or a population of organisms in an ecosystem - when there are few of these, biodiversity is likely to be high (and vice versa)

the ability of an ecosystem to resist change (maintain equilibrium) when subjected to a disruptive force

naturally occurring events which may have a negative impact on the environment e.g. eruption of Mount St Helens in 1980, the 2004 SEA earthquake and subsequent tsunami

the major cause of loss of biodiversity

when a large area of habitat is broken into many smaller areas, often physically divided by roads, towns, factories, power lines etc - leads to the loss of biodiversity

the overuse of a resource to the point that is has a negative impact on the ecosystem e.g. deforestation

when a species which is not naturally occurring in an ecosystem is introduced and may out-compete the native species - this may lead to a loss of biodiversity e.g. rabbits, cane toads, red foxes, camels in Australia

rainforests - they are called this because they are thought to produce around 40% of the oxygen that animals breath

a small area that a species inhabits - makes a species prone to extinction

caused by small populations or declining diversity - makes a species prone to extinction as they may not be able to adapt to change

some species need a large area to hunt - if there are only a few organisms over a large territory this may make them prone to extinction, especially if habitats become fragmented

due to the 10% rule, it is much more difficult for big organisms to find enough food - this makes them prone to extinction e.g. wolves, tigers

reproducing slowly and/or infrequently - this makes a species prone to extinction as it may take a long time for a population to recover its numbers

the movement between different areas at different seasons - this makes a species prone to extinction as they rely on more than one habitat - if one is destroyed, they will not survive

a species which cannot move easily to new habitats - this makes them prone to extinction - for example plants which rely on a slow dispersal of seeds, flightless birds of New Zealand

a species which requires a specific food and cannot eat others e.g. giant pandas eat bamboo shoots, koalas eat eucalyptus leaves - this makes them prone to extinction if their food source becomes scarse

the lowest number of individuals of a species needed for a population to be able to recover - if a population is lower than this number, they may become extinct

The International Union for the Conservation of Nature and Natural resources - often known as the World Conservation Union

the conservation status of species based on: population size, degree of specialisation, distribution, reproductive potential, geographic distribution and fragmentation, habitat quality, trophic level and therefore, the probability of extinction

IUCN Red List Status - no reasonable doubt that the last of a species has died

IUCN Red List Status - a species is known only to survive in cultivation, captivity or outside of its past range

IUCN Red List Status - at extreme risk of extinction in the wild

IUCN Red List Status - facing a very high risk of extinction in the wild

IUCN Red List Status - facing a high risk of extinction in the wild

IUCN Red List Status - likely to qualify as vulnerable or endangered in the near future (but does not yet)

IUCN Red List Status - widespread and abundant

IUCN Red List Status - when there is insufficient data to determine a species' status

IUCN Red List Status - when a species has not been evaluated against the criteria

United Nations

United Nations Environmental Program

Convention on International Trade in Endangered Species

United Nations Development Program

Worldwide Fund for Nature

World Resource Institute

a group of organisms sharing common characteristics that interbreed and produce fertile offspring

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

the environment in which a species normally lives

non-living, physical factors that influence the organisms and ecosystem, e.g. temperature, sunlight, pH, salinity, pollutants.

the living components of an ecosystem - organisms, their interactions or their waste - that directly or indirectly affect another organism

the particular set of abiotic and biotic conditions and resources to which an organism or population responds.

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

the actual conditions and resources in which a species exists due to biotic interactions.

factors which slow down growth of a population as it reaches its carrying capacity

the maximum number of a species or 'load' that can be sustainably supported by a given area

the study of the factors that cause changes to population sizes

when two or more individual organisms try to exploit a resource that is in limited supply

competition between members of the same species

competition between individuals of different species

when interspecific competition results in one species being driven out by the other

when one animal eats another animal

when an animal eats a plant

A symbiotic relationship where one organism (the parasite) lives in or on another (the host) feeding on or from it. One suffers, the other is harmed.

a symbiotic relationship where both species benefit.

generalised responses of populations to a particular set of conditions (biotic and abiotic factors)

a group of populations living and interacting with each other in a common habitat

a community and the physical environment it interacts with.

the conversion of organic matter into carbon dioxide and water in all living organisms, releasing energy.

the process by which green plants make their own food from water and carbon dioxide using energy from sunlight

the flow of energy from one organism to the next. It shows the feeding relationships between species in an ecosystem

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

an organism which produces its own food

make their own food from carbon dioxide and water using energy from sunlight

make their own food from simple compounds such as ammonia, hydrogen sulphide or methane, not requiring sunlight

obtain their food by eating other organisms

a complex network of interrelated food chains

quantitative models, usually measured for a given area and time. Includes pyramids of numbers, biomass and productivity

the conversion of energy into biomass over a given period of time. It is the rate of growth or biomass increase in plants and animals. It is measured per unit area per unit time.

the living mass of an organism or organisms. Measured by obtaining the dry mass and usually calculated per unit area.

a collection of ecosystems sharing similar climatic conditions

that part of the Earth inhabited by organisms. It extends from the upper atmosphere down to the deepest parts of the oceans which support life.