1. Biodiversity

Question 1

What is biodiversity

Answer 1

The variety of living organisms in an area.

Question 2

What is a species

Answer 2

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

Question 3

What is a habitat

Answer 3

The area inhibited by a species. It includes the abiotic factors (soil, temp), & the biotic factors (availability of food, predators).

Question 4

What does high biodiversity mean

Answer 4

Areas w a high biodiversity are those w lots of different species

Question 5

Biodiversity can be consider at different levels

Answer 5

1. Habitat diversity
2. Species diversity
3. Genetic diversity

Question 6

Biodiversity can be consider at different levels: Habitat diversity

Answer 6

• The no. of different habitats in an area.
• For eg, a particular area could contain many diff habitats - sand dunes, woodland, meadows, streams, etc.

Question 7

Biodiversity can be consider at different levels: Species diversity

Answer 7

• The no. of different species (species richness) & the abundance of each species (species evenness) in an area.
• For eg, a woodland could contain many diff species of plants, insects, birds & mammals.

Question 8

Biodiversity can be consider at different levels: Genetic diversity

Answer 8

• The variation of alleles within a species (or a population of a species).
• For eg, the variation of alleles within dog species give rise to diff breeds (lab, poodle).

Question 9

How can we measure biodiversity

Answer 9

Sampling - in most cases it’d be too time-consuming to count every individual organism in a habitat. Instead, a sample of the population is taken.
Estimates abt the whole habitat are based on the sample.

Question 10

What does sampling involve

Answer 10

1. Choose area to sample - small area within habitat being studied.
2. Count no. of individuals of each species (using, pitfall trap, sweep net, quadrat)
3. Repeat process - take as many samples as possible as this gives better indication of whole habitat.
4. Use results to estimate total no. of individuals/different species in the habitat.
5. When sampling different habitats & comparing them, always use same sampling technique.

Question 11

Different sampling techniques

Answer 11

How you find out how many individuals are in sample area depends on the organism you are studying.
These include for:
- Crawling ground insects
- Organisms living in long grass
- Plants

Question 12

Different sampling techniques: Crawling ground insects

Answer 12

Pitfall trap (small pit that insects cant get out of) OR pooter (device that allows you to safely suck small insects through a tube into a jar).

Question 13

Different sampling techniques: Organisms living in long grass

Answer 13

Sweep net (net lined w strong cloth on a pole)

Question 14

Different sampling techniques: Plants

Answer 14

Place a quadrat (square frame divided into grid of smaller squares) on the ground & record no. of individuals in the quadrant, or % of quadrant covered by particular species.

Question 15

Sampling can be…

Answer 15

• Random
• Non-random

Question 16

Random sampling

Answer 16

• To avoid bias in results, sample should be RANDOM
• For eg, if you were looking at plant species in field, you could pick random sample sites by dividing field into a grid using measuring tapes & using a rndm no. generator to select coordinates).

Question 17

Non-random sampling

Answer 17

• Sometimes, its necessary to take a NON-RANDOM SAMPLE
• Eg. when theres a lot of variety in the distribution of species in the habitat & you want to make sure all the diff areas are sampled.

Question 18

3 types of non-random sampling

Answer 18

1. Systematic
2. Opportunistic
3. Stratified

Question 19

What is systematic sampling

Answer 19

• When samples are taken at fixed intervals, often along a line.
• Eg, if you were counting plant species in a field, quadrats could be placed along a line (transect) from an area of shade in corner to middle of field. Each quadrat would be a sample site.

Question 20

What is opportunistic sampling

Answer 20

• When samples are chosen by the investigator.
• Used bc its simple to carry out, but data will be biased.

Question 21

What is stratified sampling

Answer 21

• When different areas in a habitat are identified & sampled separately in proportion to their part of the habitat as a whole.

Question 22

What affects biodiversity

Answer 22

• Species richness
• Species evenness

The greater the species richness & evenness in an area, the higher the biodiversity.

Question 23

What is species richness

Answer 23

• The no. of different species in an area.
• The higher the no. of species, the greater the species richness.
• Measured by taking random samples of a habitat & counting no. of diff species.

Question 24

What is species evenness

Answer 24

• Measure of the relative abundance of each species in an area.
• The more similar the population size of each species, the greater the species evenness.
• Measured by taking random samples of a habitat, & counting no. of individuals of each diff specie.

Question 25

How is diversity measured

Answer 25

Using Simpson's Index of Diversity

Question 26

What is Simpson's Index of Diversity

Answer 26

- Species present in a habitat in very small no.'s shouldn't be treated the same as those w bigger populations. - SIoD takes into account both species richness & species evenness. - SIoD is always a value 0-1 - closer to 1 the index, the more diverse the habitat. The greater the species richness & evenness, the higher the no.

Question 27

Formula for Simpson's Index of Diversity (D)

Answer 27

SEE PG111 FOR FORMULA + EG n = total no. of individuals of one species N = total no. of organisms of all species Σ = sum of D = 1 - (Σ (n/N)^2 ) - GIVEN IN EXAM