3.7.4 Populations in ecosystem

Part of ecosystem in which organisms live

A community and non living components of an environment(biotic/abiotic factors).

An organisms role within an ecosystem. Can lead to competition

Interspecific = competition between memebers of different species for resources/habitats
Intraspecific = compettion between member of same species for usually MATES

Used to estimate population size when theyre unevenly distributed eg sandy shores

BELT TRANSECT:Quadrat placed at every position along tape.
INTERRUPTED BELT TRANSECT: Quadrat placed at intervals along tape eg every 5 metres

1)Place tape measure at right angle to shore line
2)Place quadrats at every interval/every position
3)Collect data
4)Repeat by placing another 30 transects along beach at right angles to shore line

1)Capture initial sample ethically, count how many and mark them.
2)Release them and wait for a period of time so they randomly disperse
3)Capture second sample and count how many captured and how many of them are marked
- This data is then used to calculate size of population.

Non-toxic and doesnt harm
Doesnt increase chance of predation
DOesnt reduce chance of reproduction

Assumes population size is constant and animals distribute evenly across