4.4 Genetic Diversity

Question 1

Define genetic diversity

Answer 1

The number of different alleles of genes in a population

Question 2

Reasons for low levels of Genetic Diversity

Answer 2

• Small population
• Inbreeding

Question 3

Explain the process of natural selection

Answer 3

• A random mutation occurs in one cell, resulting in a new allele in a gene for XXX
• YYY provides a selection pressure
• The cell is more likely to survive, and reproduce, passing on allele to offspring
• Over generations, the allele increases in frequency in the population

Question 4

Why is there a time lag on a graph showing resistance

Answer 4

• Initally, only one individual has the desired allele
• Indiviiduals with allele will survivie to produce more offspring
• It takes many generations for the allele to increase in frequency in the population
• Become most dominant

Question 5

What are the type of adaptations that are created by natural selection

Answer 5

• Anatomical
• Physiological
• Behavioural

Question 6

Explain stabilising selection, and give an example

Answer 6

• Intermediate phenotypes best adapted to survivie in enviroment
• As intermediate phenotypes are advantageous, they become more common
• Extreme phenotypes disappear
• Birth weight in humans

Question 7

Example of stabilising selection

Answer 7

Birth weight in humans

Question 8

Explain directional selection and give an example

Answer 8

• Extreme phenotype is best adapted to survive in enviroment
• As extreme phenotypes are advantageous, they become more common, and intermediate phenotypes disappear
• Antibiotic resistance in rats

Question 9

Example of directional selection

Answer 9

Antibiotic resistance in rats