environmental pressures
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)
biodiversity
a combination of the species diversity, genetic diversity and habitat diversity of an ecosystem
variation
the differences, either physical or genetic, between individuals of a species
simpson's diversity index
a measure of diversity between similar ecosystems
species diversity
the number of species (richness) and their relative proportions (evenness) in a community
genetic diversity
the range of genetic material present in a gene pool or population of a species
random genetic mutations
the small differences which may occur in an organism as a result of reproduction - these small changes may add up to create variation
hotspots
an area of high biodiversity (which is under threat from human activities)
endemic species
the species which only occur in one specific area
speciation
the gradual change in populations of a species over time - often caused by geographical isolations, resulting in new species
evolution
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
natural selection
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
geographical isolation
the separation of populations of a single species - often leads to speciation if populations cannot interbreed for a very long time
physical barriers
e.g. a mountain, ocean or separation of lakes
land bridges
a connection between land masses - often as a result of lowering sea levels e.g. the Bering Straits
continental drift
the movement of the tectonic plates by around 1cm a year causing the change in shape and location of continents
lithosphere
the Earth's crust - the rocky part of Earth
Gondwana
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
background extinction rate
the natural rate of extinction of species - around 1 species per million species per year
extinction
the complete loss of a species from Earth - no more individuals of that species exist
mass extinctions
an extinction rate far greater than background extinction rate
Holocene extinction event
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
weedy species
the species (generally plant or animal) which are able to survive the environments we create e.g. urban rats, domesticated animals
Living Planet Report
a report produced by the Worldwide Fund for Nature (WWF) creates on the state of the world's ecosystems
conservation
the act of preserving nature - attempting to save habitats, species and biodiversity in general
2/3
the proportion of living species which are found in tropical rainforests
current extinction rates
approx. 100 species per million species per year
ecosystem complexity
creates stability and resilience to change in an ecosystem - there are many pathways for energy flow
limiting factors
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)
inertia
the ability of an ecosystem to resist change (maintain equilibrium) when subjected to a disruptive force
natural hazards
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
habitat loss
the major cause of loss of biodiversity
habitat fragmentation
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
overexploitation
the overuse of a resource to the point that is has a negative impact on the ecosystem e.g. deforestation
introduction of non-native species
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
lungs of the Earth
rainforests - they are called this because they are thought to produce around 40% of the oxygen that animals breath
narrow geographical range
a small area that a species inhabits - makes a species prone to extinction
low genetic diversity
caused by small populations or declining diversity - makes a species prone to extinction as they may not be able to adapt to change
low population density
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
large body
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
low reproductive potential
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
seasonal migration
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
poor dispersers
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
specialised feeders
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
minimum viable population size
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
IUCN
The International Union for the Conservation of Nature and Natural resources - often known as the World Conservation Union
made up of government agencies, states, non-governmental organisations (NGOs) and scientists and experts - their goal is to conserve nature and increase sustainability of resource use
IUCN Red List
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
extinct (EX)
IUCN Red List Status - no reasonable doubt that the last of a species has died
extinct in the wild (EW)
IUCN Red List Status - a species is known only to survive in cultivation, captivity or outside of its past range
critically endangered (CR)
IUCN Red List Status - at extreme risk of extinction in the wild
endangered (EN)
IUCN Red List Status - facing a very high risk of extinction in the wild
vulnerable (VU)
IUCN Red List Status - facing a high risk of extinction in the wild
near threatened (NT)
IUCN Red List Status - likely to qualify as vulnerable or endangered in the near future (but does not yet)
least concern (LC)
IUCN Red List Status - widespread and abundant
data deficient (DD)
IUCN Red List Status - when there is insufficient data to determine a species' status
not evaluated (NE)
IUCN Red List Status - when a species has not been evaluated against the criteria
UN
United Nations
UNEP
United Nations Environmental Program
CITES
Convention on International Trade in Endangered Species
UNDP
United Nations Development Program
WWF
Worldwide Fund for Nature
WRI
World Resource Institute
species
a group of organisms sharing common characteristics that interbreed and produce fertile offspring
population
a group of organisms of the same species living in the same area at the same time, and which are capable of interbreeding
habitat
the environment in which a species normally lives
abiotic factors
non-living, physical factors that influence the organisms and ecosystem, e.g. temperature, sunlight, pH, salinity, pollutants.
biotic factors
the living components of an ecosystem - organisms, their interactions or their waste - that directly or indirectly affect another organism
niche
the particular set of abiotic and biotic conditions and resources to which an organism or population responds.
fundamental niche
the full range of conditions and resources in which a species could survive and reproduce
realised niche
the actual conditions and resources in which a species exists due to biotic interactions.
limiting factors
factors which slow down growth of a population as it reaches its carrying capacity
carrying capacity
the maximum number of a species or 'load' that can be sustainably supported by a given area
population dynamics
the study of the factors that cause changes to population sizes
competition
when two or more individual organisms try to exploit a resource that is in limited supply
intraspecific competition
competition between members of the same species
interspecific competition
competition between individuals of different species
competitive exclusion
when interspecific competition results in one species being driven out by the other
predation
when one animal eats another animal
herbivory
when an animal eats a plant
parasitism
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.
mutualism
a symbiotic relationship where both species benefit.
S and J population curves
generalised responses of populations to a particular set of conditions (biotic and abiotic factors)
community
a group of populations living and interacting with each other in a common habitat
ecosystem
a community and the physical environment it interacts with.
respiration
the conversion of organic matter into carbon dioxide and water in all living organisms, releasing energy.
photosynthesis
the process by which green plants make their own food from water and carbon dioxide using energy from sunlight
food chain
the flow of energy from one organism to the next. It shows the feeding relationships between species in an ecosystem
trophic level
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
producers (autotrophs)
an organism which produces its own food
photoautotrophs (green plants, algae, etc)
make their own food from carbon dioxide and water using energy from sunlight
chemoautotrophs
make their own food from simple compounds such as ammonia, hydrogen sulphide or methane, not requiring sunlight
consumers (heterotrophs)
obtain their food by eating other organisms
food web
a complex network of interrelated food chains
ecological pyramids
quantitative models, usually measured for a given area and time. Includes pyramids of numbers, biomass and productivity
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.
biomass
the living mass of an organism or organisms. Measured by obtaining the dry mass and usually calculated per unit area.
biome
a collection of ecosystems sharing similar climatic conditions
biosphere
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.