11.4 Calculating Biodiversity & Genetic Biodiversity

Question 1

How to calculate BD

Answer 1

Count up the no. of species present (species richness). However this doesn’t take into account the np. of individuals present.

Simpson’s Index of Diversity (D) is the better measure of BD as it accounts for species richness and evenness.

D= 1- (sum of)(total no. of organisms in one species/total no. of organisms of all species)^2

Always results in a value between 0 and 1; 0 is no BD, 1 is a lot of BD.

Question 2

Why do we Calculate Genetic BD

Answer 2

To monitor health of the popn. and ensure long-term survival.

Question 3

Importance of GBD

Answer 3

Within a species, individuals have very little variation within their DNA. All members of a species share the same genes however, they have different versions called alleles. These differences create variation and genetic biodiversity within the popn.
The more alleles, the more GBD.

Species that contain greater GBD are more likely to be better at adapting to environmental changes and so are less likely to become extinct.

Question 4

Measuring GBD

Answer 4

Measuring polymorphism; polymorphic genes have more than one allele.

For example, in blood types, different alleles exist for the immunoglobin gene, which determines human blood type.

Most genes aren’t polymorphic, those re monomorphic. Ensures a basic structure of individuals within a species remains consistent.

Proportion of polymorphic gene loci = no. of polymorphic gene loci / total no. of loci

(Loci refers to place of gene on the chromosome)>