3.7.4 - POPULATIONS IN ECOSYSTEMS Flashcards
give two conditions for results from mark-release-recapture investigation to be valid (2)
- marking does not affect predation
- no immigration
- sufficient time for marked individuals to mix with the population
- no/little births/deaths/breeding
what is a community? (2)
populations of different species occupying the same place at the same time
what is an ecosystem? (2)
- community and the non-living components of an environment.
- ecosystems can vary in size
what is a habitat? (1)
the part of an ecosystem in which a particular organisms lives
what is the carrying capacity? (1)
the maximum population size an ecosystem can support
what is a niche? (2)
- an organisms role within an ecosystem (including its position in food web and its habitats))
- each species occupies its own niche, governed by adaptation to both biotic and abiotic conditions
suggest one reason for conserving woodlands (1)
- conserving habitats
- protecting endangered species
- reduces greenhouse effect/global warming
succession occurs in natural ecosystems.
describe and explain how succession occurs (4)
- colonisation by pioneer species
- pioneer species changes the environment
- so environment becomes less hostile and more suitable for other species
- change/increase in biodiversity
- to climax community
the sundew is a small flowering plant, growing in wet habitats such as bogs and marshes. the soil in bogs and marshes is acidic and has very low concentrations of some nutrients. the sundew can trap and digest insects.
describe how you could estimate the size of a population of sundews in a small marsh (5)
- use a grid OR divide areas into squares/sections
- use random number generator
- count number/frequency in a quadrat
- large sample and calculate mean
the sundew is a small flowering plant, growing in wet habitats such as bogs and marshes. the soil in bogs and marshes is acidic and has very low concentrations of some nutrients. the sundew can trap and digest insects.
