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A level Biology > Biodiversity > Flashcards

Flashcards in Biodiversity Deck (10):
1

What is sampling?

Taking measurements of a limited number of individual organisms present in a particular area

2

What does the abundance of an organism tell us

The number of individuals of a species present in an area

3

What is random sampling

Means selecting individuals by chance

4

What is non random sampling

When the sample is not random

5

What are the three main techniques if non random sampling

Opportunistic
Stratified
Systematic

6

Explain opportunistic sampling

Weakest form of sampling. Uses organisms the are conveniently available.

7

Explain stratified sampling

Population can be divided into a number of strata based in particular characteristics. A random sample is then taken from each strata proportional to its size.

8

Explain systematic sampling

Areas within an overall population are identified and sampled separately. Often carried out using a line or belt transect.

9

What is sample bias

Selection may be biased. May be by accident or deliberate. Effects may be reduced using random sampling.

10

What is chance

Organisms selected may by chance not be representative of the whole population. Can never be completely removed. Can be minimised using a larger sample.