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 version of the same gene found at the same locus on a chromosome

Question 3

Define genetic diversity

Answer 3

Total number of different alleles in a population

Question 4

What advantage does a high Genetic Diversity provide?

Answer 4

The ability to adapt to a change in environment (allows natural selection to occur)

Question 5

How does Natural Selection result in development of new characteristics?

Answer 5

• Random mutations result in new alleles
• Some alleles provide an advantage making an 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
- Overtime the mean of the population will move towards these characteristics

Question 7

Give an example of Directional selection

Answer 7

Antibiotic resistance
- Bacteria with a mutation allowing them to survive in the presence of antibiotics will reproduce
- Therefore frequency of this allele will increase and the population will shift to have greater antibiotic resistance

Question 8

What is Stabilising selection?

Answer 8

Occurs when 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 Stabilising selection

Answer 9

Birth weight
- Babies that weigh around 3 kilogrammes are more likely to survive than those at lower or higher weights

Question 10

Define a niche

Answer 10

The role of a species within its environment and species sharing the same niche will compete with each other

Question 11

What are the 3 types of adaption?

Answer 11

• Anatomical
• Physiological
• Behavioural

Question 12

What is meant by Anatomical?

Answer 12

Changes to body structure e.g. oily fur

Question 13

What is meant by Physiological?

Answer 13

Changes to bodily processes e.g. venom production

Question 14

What is meant by Behavioural?

Answer 14

Changes to actions e.g. hibernation