3.4.4 Genetic diversity and adaptation

Question 1

Define population

Answer 1

All the organisms of a particular species that live in the same place

Question 2

What is an allele

Answer 2

Different forms of a particular gene

Question 3

Define genetic diversity

Answer 3

The total number of different alleles in a population

Question 4

What advantage does a high genetic diversity produce

Answer 4

Ability to adapt to a change in environment; allows natural selection to occur

Question 5

Explain how natural selection results in development of new characteristics

Answer 5

Random mutations result in new alleles
Some alleles provide an advantage, making individual more likely to survive and reproduce
Their offspring receive the new allele and frequency continues to increase over many generations

Question 6

What is directional selection

Answer 6

Occurs when environmental conditions change
Individuals with phenotypes suited to the new conditions will survive and pass on their genes
Over time the mean of the population will move towards these characteristics

Question 7

Give an example of directional selection

Answer 7

Antibiotic resistance
Bacteria with mutation can survive and can reproduce therefore frequency of allele increase and population shifts to have greater resistance

Question 8

What is stabilising selection

Answer 8

Occurs when the environmental conditions stay the same
Individuals closest to the mean are favoured and any new characteristics are selected against
Results in low diversity

Question 9

Give an example of a stabilising selection

Answer 9

Birth weight
Babies that weigh around 3kg are more likely to survive

Question 10

Define a niche

Answer 10

The role of a species within its environment
Species sharing same niche will compete with eachother

Question 11

What are the 3 types of adaption
Give examples of each

Answer 11

Anatomical - body structure eg oily fur
Physiological - body processes eg venom production
Behavioural - actions eg hibernation