4.4 - Genetic Diversity & 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,
Found at the same locus on a chromosome.
A single gene could have many alleles.

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 provide?

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 & reproduce.
• their offspring receive 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, 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 presence of antibiotics will reproduce.
So frequency of this allele will increase & population will shit 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

Give an example of stabilising selection.

Answer 9

Birth weight.
Babies with average birth weight are more likely to survive than those with lower or higher weights.

Question 10

Define a niche.

Answer 10

The role of a specieswithin 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 an anatomical adaptation. Give an example.

Answer 12

Changes to body structure
E.g. oily fur

Question 13

What is a physiological adaptation? Give an example.

Answer 13

Changes to bodily processes
E.g. venom production

Question 14

What is an behavioural adaptation? Give an example.

Answer 14

Changes in actions
E.g. hibernation