4.4 Genetic diversity and adaptation

Question 1

What is a 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, found at the same locus on a chromosome. A single gene could have many alleles

Question 3

What is genetic diversity?

Answer 3

the total number of different alleles in a population

Question 4

What advantage does a high genetic diversity provide?

Answer 4

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

Question 5

How does natural selection result in the 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.
• Over time the mean of the population will move towards these characteristics

Question 7

Whats an example of direction 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 a 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

What is an example of stabilising selection?

Answer 9

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

Question 10

What is a niche?

Answer 10

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

Question 11

What are the 3 types of adaptation?

Answer 11

• anatomical
• physiological
• behavioural

Question 12

What is anatomical adaptation?

Answer 12

• changes to a body structure
• e.g. oily fur, shorter ears, thicker fur

Question 13

What is physiological adaptation?

Answer 13

• changes to bodily processes
• e.g. venom production, oxidising of fat

Question 14

What is behavioural adaptation?

Answer 14

• changes to actions
• e.g. hibernation, migration