4.2.1 Biodiversity

Question 1

Importance of biodiversity

Answer 1

Maintains a balanced ecosystem
All species interconnected
Provide food, oxygen, raw materials

Question 2

Measuring biodiversity; levels of study

Answer 2

• habitat biodiversity
• species biodiversity
• genetic biodiversity

Question 3

Habitat biodiversity

Answer 3

Number of diff habitats in an ears

Each supports number of species
Greater the habitat greater the biodiversity

e.g. meadow,woodland,streams

Question 4

Species biodiversity

Answer 4

Two components:

• species richness
(no of diff species living in that area)

• species evenness
(numbers of each species in that area)

Question 5

Genetic biodiversity

Answer 5

Variety of genes that make up a species

Diff alleles of each gene = genetic biodiversity

Question 6

What is sampling?

Answer 6

Means taking measurements of a limited number of organisms present in a particular area

Question 7

Random sampling

Answer 7

1) mark out a grid on the grass using two tape measures laid at right angles
2) use random numbers to determine the x and y coordinates on grid
3) take a sample at each coordinate

Question 8

Non-random sampling; Opportunistic

Answer 8

Weakest form of sampling

Uses organisms that are conveniently available

Question 9

Non-random sampling; Stratified

Answer 9

Populations divided into strata based on particular characteristic

Question 10

Non-random sampling; Systematic

Answer 10

Diff areas within habitat identified, sampled separately

Belt or line transect

Question 11

Reliability of sampling

Answer 11

• sampling bias - selection process may me biased

* chance - may not be representative of the whole population

Question 12

Sampling animals

Answer 12

• a pooter for small insects
• sweep nets for insects in long grass
• pitfall traps for small invertebrates
• tree beating
• kick sampling

Question 13

Sampling plants

Answer 13

Using quadrat
• point quadrat - frame w horizontal bar. Each species pin touches is recorded
• frame quadrat - grid

Question 14

Species richness

Answer 14

A measure of the number of different species living in a specific area

Use a combination of sampling techniques to measure

Question 15

Species evenness

Answer 15

How close in numbers the populations of each species in an environment are

Question 16

Using frame quadrats

Answer 16

• density
• frequency
• percentage cover

Question 17

Estimating animal population size

Answer 17

Capture, mark, release, recapture

Question 18

Measuring abiotic factors

Answer 18

Abiotic = non-living conditions
e.g. light and water availability

Probes/sensors:
• rapid changes detected
• human error is reduced 
• high precision 
• data stored and tracked on computer

Question 19

Calculating biodiversity; Simpson’s Index of Biodiversity

Answer 19

N = total no of organisms of all species
n = total no of organisms of a particular species 

0=no diversity
1=infinite diversity