Genetic Diversity and Adaptation

Question 1

What is genetic diversity?

Answer 1

The variety of alleles present in a population

Question 2

Explain how natural selection occurs

Answer 2

Mutation leads to the presence of different alleles within a population. Some of these alleles may be advantageous to the species, some may be disadvantageous. Depending on the environmental selection pressures, those with disadvantageous traits are selected against. Those with advantageous traits are more likely to survive and pass on their genes. Over time, the frequency of the advantageous allele will become more prevalent, whereas the disadvantageous alleles will be less frequent - this is natural selection.

Question 3

Describe directional selection, and give an example

Answer 3

Directional selection is where one extreme either side of the mean is favourably selected, the population will shift in this direction. E.g. antibiotic resistance

Example sentence: Antibiotic resistance is an example of directional selection

Question 4

Describe stabilising selection, and give an example

Answer 4

Stabilising selection is where the mean is favourable, and the extremes either side of the mean are selected against. E.g. human birth weight

Example sentence: Human birth weight is an example of stabilising selection

Question 5

What are the different types of adaptation?

Answer 5

Behavioural, physiological, anatomical

Question 6

What is an anatomical adaptation?

Answer 6

Anatomical adaptations are physical features e.g. the organism’s shape. Examples include having shorter ears and thicker fur to reduce heat loss to the environment

Example sentence: Anatomical adaptations help organisms survive in their environment

Question 7

What is a physiological adaptation?

Answer 7

A physiological adaptation is an adaptation at the cellular or molecular level. Examples include oxidising fat rather than carbohydrates to produce additional water in desert animals

Example sentence: Physiological adaptations enable animals to thrive in extreme conditions

Question 8

What is a behavioural adaptation?

Answer 8

Behavioural adaptations are where the activities of an organism are suited to their environment. Examples include migration or being nocturnal

Example sentence: Behavioural adaptations help organisms survive by changing their behavior