section 2: biodiversity - topic 1: investigating biodiversity

Question 1

what does biodiversity mean?

Answer 1

it refers to the variety of living organisms in an area.

Question 2

what are the 3 levels of biodiversity?

Answer 2

habitat diversity.
species diversity.
genetic diversity.

Question 2

what is a habitat?

Answer 2

the area inhabited by a species.

Question 3

what is habitat diversity?

Answer 3

the number of different habitats in an area.

Question 3

what is a species?

Answer 3

a group of similar organisms able to reproduce to give fertile offspring.

Question 4

what is species diversity?

Answer 4

the number of different species (species richness) and the abundance of each species (species evenness) in an area.

Question 5

what is genetic diversity?

Answer 5

the variation of alleles (versions of a gene) within a species or population of a species.

Question 6

how do you collect data on biodiversity?

Answer 6

by finding out the number of different species in a habitat or the number of individuals in each species.

Question 7

what are the 2 categories of sampling?

Answer 7

random.
non-random.

Question 8

what are the 3 types of non-random sampling?

Answer 8

systematic.
opportunistic.
stratified.

Question 9

how would you conduct random sampling?

Answer 9

if you were looking at plant species in a field you could pick random sample sites by dividing the field into a grid using measuring tapes and use a random number generator to select coordinates.
^ makes sure that each sample site has the same probability of being chosen.

Question 10

when is it necessary to take a non-random sample?

Answer 10

when there’s a lot of variety in the distribution of a species in the habitat and you want to make sure that all the different areas are sampled or that all the different species are sampled.

Question 11

what is systematic sampling?

Answer 11

when samples are taken at fixed intervals, often along a line.

Question 12

example of systematic sampling.

Answer 12

if you were looking at plant species in a field, quadrants could be placed along a line (a transect) from an area of shade in the corner to the middle of the field.
each quadrant would then be a sample site.

Question 13

what is opportunistic sampling?

Answer 13

this is when samples are chosen by the investigator.
it’s used because it is simple to carry out, but the data will be biased.

Question 14

what is stratified sampling?

Answer 14

this is when different areas in a habitat are identified and sampled separately in proportion to their part of the habitat as a whole.

Question 15

example of stratified sampling.

Answer 15

a heathland may have patches of gorse in it - the heath and gorse areas would be sampled separately according to how much of each there was in the habitat.

Question 16

describe the PAG of estimating biodiversity using samples.

Answer 16

1. choose a site to sample.
2. record the number of different species or count the number of individuals of each species.
3. repeat the process - take as many samples as possible. this gives a better indication of the whole habitat. all samples should be chosen in the same way as your first.
4. the number of individuals for the whole habitat can then be estimated by calculating the mean for the data collected in each sample and multiplying it by the size of the whole habitat.
5. when sampling different habitats and comparing them, always use the same sampling technique.

Question 17

what is species richness?

Answer 17

the number of different species in an area.