Genetic diversity & adaptation

Question 1

Define Population

Answer 1

All organisms of particular species that live in same place

Question 2

Define Genetic Diversity

Answer 2

Total no. of different alleles in population

Question 3

What advantage does high genetic diversity provide?

Answer 3

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

Question 4

Explain how natural selection results in development of new characteristics

Answer 4

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

Question 5

What is directional selection?

Answer 5

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

Question 6

Give example of directional selection

Answer 6

Antibiotic resistance. Bacteria with mutation allowing them to survive in presence of antibiotics will reproduce. So frequency of this allele will increase & the population will shift to have greater antibiotic resistance

Question 7

What is stabilising selection?

Answer 7

Occurs when environmental conditions stay same. Individuals closest to mean are favoured, & any new characteristics are selected against.

Result in low diversity

Question 8

Give example of stabilising selection

Answer 8

Birth weight; babies that weigh 3kg are more likely to survive than those at lower or higher weights

Question 9

Define a niche

Answer 9

Role of a species within its environment. Species sharing same niche will compete with each other

Question 10

What are 3 types of adaptation? (give examples)

Answer 10

• Anatomical (changes body structure) e.g. oily fur
• Physiological (changes to bodily processes) e.g. venom production
• Behavioural (changes to actions) e.g. hibernation