Genetic diversity and natural selection

Question 1

What is genetic diversity?

Answer 1

The number of different alleles of a gene in a species or population

Question 2

What increases genetic diversity?

Answer 2

Mutations in DNA which forms new alleles
Introduction of different alleles in a population when individuals from another population migrate into them and reproduce (gene flow)

Question 3

How is genetic diversity decreased?

Answer 3

By genetic bottlenecks (founder effect)

Question 4

What is a genetic bottleneck and what do they do?

Answer 4

An event that causes a big reduction in a population.
It reduces the number of different alleles in a gene pool and decreases the genetic diversity. Survivors reproduced and a bigger population is created from a few individuals

Question 5

What is natural selection?

Answer 5

When the allele codes for a characteristic that increases the chance of an organisms survival increases in frequency

Question 6

What does natural selection lead to?

Answer 6

A better adapted population

Question 7

Name and explain the 3 types of adaptation that occur as a result of natural selection

Answer 7

Behavioural adaptations - ways an organisms acts that increases the chance of survival and reproduction
Physiological adaptations - processes inside an organisms body that increases the chance of survival and reproduction
Anatomical adaptations - structural features of an organism that increases the chance of survival and reproduction

Question 8

Name 2 types of natural selection

Answer 8

Directional selection
Stabilising selection

Question 9

What is directional selection?

Answer 9

Where individuals with alleles for characteristics of an extreme type are more likely to survive and reproduce. Could be in response to an environmental change.

Question 10

What is stabilising selection?

Answer 10

Where individuals with alleles for characteristics towards the middle of the range are more likely to survive and reproduce. Occurs when the environment isn’t changing.