Calculating biodiversity 11.4

Question 1

what is species diversity normally proportional to

Answer 1

habitat stability
the greater the species diversity the greater the habitat stability

Question 2

what is Simpsons index of diversity (D)
and what is its formula

Answer 2

It is a measure of biodiversity that takes into account both species richness and evenness

Question 3

what do the values of the simpsons index of diversity mean

Answer 3

simpsons index of diversity always results in a value between 0 and 1, where 0 always represents no diversity and a value of 1 represents infinite diversity.
The higher the value of simpsons index of diversity the more diverse the habitat

Question 4

what do low and high biodiversity values tell us about a habitat

Answer 4

Question 5

Why is genetic biodiversity important

Answer 5

All members of a species share the same genes. However, they may have different versions of some of these genes (alleles).

Species that contain greater genetic biodiversity are likely to be able to adapt to change in their environment, and hence are less likely to become extinct. This is because there are likely to be some organisms within the population that carry an advantageous allele, which enables them to survive In altered conditions.

Question 6

what are some factors that can increase genetic biodiversity

Answer 6

• mutations in the DNA of an organism
  ^creating a new allele.
• breeding between different populations. (gene flow)

Question 7

what is meant by gene flow

Answer 7

when an individual migrates from one population and breeds with a member of another population, alleles are transferred between the two populations. This is known as gene flow

Question 8

Name some factors that can decrease genetic biodiversity

Answer 8

• selectively breeding
• captive breeding programmes
• rare breeds
• artificial cloning
• natural selection
• genetic bottlenecks
• the founder effect
• genetic drift

Question 9

How can selective breeding decrease genetic biodiversity

Answer 9

only a few individuals within a population are selected for their advantageous characteristics and bred. For example, the breeding of pedigree animals or of human food crops

Question 10

How can capative breeding lead to deacreased genetic biodiversity

Answer 10

Captive breeding programmes in zoos and conservation centres, where only a small number of captive individuals of a species are available for breeding. Often the wild population is endangered or extinct

Question 11

Why do rare breeds often have lower genetic biodiversity

Answer 11

when only a small number of individuals of a breed remain and are available for breeding and all of these animals will have been selected for the specific breed traits, the genetic diversity of the remaining population will be low. This can cause serious problems when trying to restore numbers yet maintain breed characteristics, for example a Gloucester old spot pig must have at least one spot on the body to be accepted into the registry of this rare breed

Question 12

How can natural selection cause decreased genetic biodiversity

Answer 12

species will evolve to contain primarily the alleles which code for advantageous characteristics. Over time, alleles coding for less advantageous will be lost from a population, or only remain in a few individuals

Question 13

What is genetic bottlenecks and how can it cause a decrease in genetic biodiversity

Answer 13

where few individuals within a population survive an event or change (disease, environmental change or habitat destruction), thus reducing the gene pool. Only the alleles of the surviving members of the population are available to be passed on to offspring

Question 14

What is the founder effect and how can it cause decreased genetic biodiversity

Answer 14

where a small number of individuals create a new colony, geographically isolated from the original. The gene pool for this new population is small

Question 15

What is genetic drift and how can it cause decreased genetic biodiversity

Answer 15

due to the random nature of alleles being based on from parents to their offspring, the frequency of occurrence of an allele will vary. In some cases, the existence of a particular allele can disappear from a population altogether. Genetic drift is more pronounced in populations with a low genetic biodiversity

Question 16

which is one way scientists quantify genetic biodiversity

Answer 16

One way is by measuring polymorphism

Question 17

What do polymorphic genes have more than one of

Answer 17

polymorphic genes have more than one allele
For example, different alleles exist for the immunoglobulin gene, which plays a role in determining human blood type-this is therefore defined as a polymorphic gene. The 3 allele are:
- I^A resulting in the production of antigen A
- I^B resulting in the production of antigen B
- I^O resulting in the production of neither antigen

Question 18

Are more genes polymorphic or monomorphic

Answer 18

most genes are not polymorphic

Question 19

What does monomorphic mean

Answer 19

a single allele exists for the gene

Question 20

Why are most genes monomorphic

Answer 20

This ensures that the basic structure of individuals within a species remains consistent.

Question 21

what formula can be used to calculate the proportion of genes that are polymorphic

Answer 21

Question 22

what are loci

Answer 22

The locus (plural-loci) of a gene refers to the position of the gene on a chromosome

Question 23

How is the proportion of polymorphic gene loci related to genetic biodiversity

Answer 23

The greater the proportion of polymorphic gene loci, the greater the genetic biodiversity within the population