Biodiversity-4.2

Question 1

Define biodiversity

Answer 1

A measure of the variation found in the living world

Question 2

Define a species

Answer 2

A group of individual organisms that are very similar in appearance ,anatomy, physiology,biochemistry and genetics. Whose members are able to reproduce freely to produce fertile offspring.

Question 3

What is a habitat?

Answer 3

A place where an organism lives

Question 4

What is habitat biodiversity?

Answer 4

-the range of habitats in which different species live
-e.g. sand dunes, woodland,meadows,streams

Question 5

What contributes to species biodiversity?

Answer 5

Species richness and species evenness

Question 6

What is genetic biodiversity?

Answer 6

-different breeds within a species

Question 7

How can non-random sampling be carried out?

Answer 7

-sample sites are randomly selected
-e.g.
.using randomly generated numbers as coordinates for your samples

Question 8

What is the advantage of random sampling?

Answer 8

-ensures that the data is not biased by selective sampling

Question 9

What are the disadvantages of random sampling?

Answer 9

-may not cover all areas of habitat equally
-species with a low presence may be missed, leading to an underestimate of biodiversity

Question 10

What are three examples of non-random sampling?

Answer 10

-opportunistic
-stratified
-systematic

Question 11

How is opportunistic sampling carried out?

Answer 11

-when the researcher makes sampling decisions based on prior knowledge or during the process of collecting data
-the researcher may deliberately sample an area that they know or can see contains a particular species

Question 12

What are the advantages of opportunistic sampling?

Answer 12

-easier and quicker than random sampling

Question 13

What are the disadvantages of opportunistic sampling?

Answer 13

-the data may be biased
-can lead to an overestimate of biodiversity or an overestimate of a particular species (e.g. if it is very colourful?

Question 14

How is stratified sampling carried out ?

Answer 14

-dividing a habitat into areas that appear different and sampling each area separately

Question 15

What are the advantages of stratified sampling?

Answer 15

-ensures that all different areas of habitat are sampled and species are not underrepresented due to the possibility that random sampling misses certain areas

Question 16

What are the disadvantages of stratified sampling?

Answer 16

-may lead to the over-representation of some areas in the sample
-e.g. a disproportionate number of samples are taken in small areas that look different

Question 17

How is systematic sampling carried out?

Answer 17

-when samples are taken at fixed intervals across the habitat
-e.g. line transects and belt transects

Question 18

What is an advantage of systematic sampling?

Answer 18

-very useful when the habitat shows a clear gradient in some environmental factors
-such as getting drier further from a pond

Question 19

What is a disadvantage of systematic sampling?

Answer 19

-only the species on the line or within the belt can be recorded
-other species may be missed, leading to an underestimate of biodiversity

Question 20

What is species evenness?

Answer 20

• a measure of how evenly represented the species are
  -to measure this you need to carry out a quantitative survey

Question 21

What is species richness?

Answer 21

-a measure of how many different species are present
-to measure you need to count all the species present in a habitat

Question 22

How can you interpret the value of Simpson’s index?

Answer 22

-a high value indicates a diverse habitat-the habitat tends to be more stable and able to withstand change

-a low value indicates a habitat dominated by a few species- a small change to the environment (e.g. a disease, a new predator) that affects one of those species species could damage or destroy the whole habitat.