All living things and their surrounding make up an ecosystem.
Many ecosystems are still unexplored and could contain new species.
Artificial Ecosystems - usually controlled using pesticides(control pests), herbicides (remove weeds) and fertilisers(increase crop yield)
Keys-can be used to identify the animals and plants in a habitat
Different counting methods are used to estimate populations.estimates are often inaccurate if the sample size is not large enough. To increase accuracy- repeat the process, make the sample size as large as possible.
Quadrats- method of this. place on ground in a random way (fairness). Percentage cover of each plant is recorded.
pop formula - no of animals 1st x no of animals 2nd
no of marked animals 2nd