ecosystems Flashcards
how can you measure wind speed?
anemometer
list 3 biotic factors that influence small mammals living in woodlands
- predation
- disease
- competition
how to work out population size of an area
mean number of individuals in quadrat / fraction of the total habitat covered by 1 quadrat
what is the definition of systematic sampling
investigating changes along an environmental gradient
what is the most crucial aspect of stratified sampling
sample each area proportional to its size as a percentage of whole habitat
what is opportunistic sampling and why is this a weakness?
based on prior knowledge e.g. safe areas - may not be representative
what is a climax community
final community that is stable and changes very little overtime.
what is succession
progressive change in an ecosystem overtime
when does secondary succession occur
once all land has been cleared of all plants and animals, but the soil remains
what is deflected succession
occurs when human activities prevent succession, stopping the normal climax community forming = this community is instead called plagioclimax
how does primary succession cause change in conditions
pioneer species build up dead organic matter and increase water in soil so that other species can survive
as succession increases…
ecosystem becomes more complex, soil organic matter and nutrient levels increase, more niches available and total biomass increases
general adaptations of pioneer species
- large number of seeds
- seeds germinate easily
- tolerance to extreme conditions
- ability to fix nitrogen
biomass
the mass of living material, including organic and inorganic components and can be used to determine energy content.
why does plant matter vary?
due to fluctuations in water uptake and transpiration
