Genetic Diversity And Natural Selection

Question 1

What is genetic diversity?

Answer 1

The number of different alelles or genes in a species or population

Question 2

Factors that increase genetic diversity within a population

Answer 2

• mutations in the DNA forming new alleles
• Different alleles being introduced into a population when the individuals from another population migrate to them and reproduce( gene flow)

Question 3

What is a genetic bottleneck?

Answer 3

An event that causes a big reduction in a population

Question 4

What does genetic bottleneck cause?

Answer 4

• Reduces the number of different values in the gene pool so reduces genetic diversity
• Survivors reproduce and a larger population is created from few individuals

Question 5

What is the founder effect?

Answer 5

Describe what happens when just a few organisms from a population start a new colony and there are only a small number of different alleles in the initial gene pool

Question 6

What happens to the gene frequencies in the founder effect?

Answer 6

The frequency of each allele might be very different
- For example and allele that was rare in the original population might be more common in the new colony

Question 7

What can the founder affect lead to?

Answer 7

Higher incidence of genetic disease

Question 8

Natural selection increases advantageous alleles in a population
- Describe how this happens

Answer 8

• Not all individuals are as likely to reproduce as each other
• Individuals that have an allele which increases their chance of survival are more likely to survive reproduce and pass on their genes
• This means that a greater proportion of the next generation inherit the beneficial allele
• b they intern are more likely to survive, reproduce and pass on their genes
• Say the frequency of beneficial allele increases from generation to generation
• This leads to evolution

Question 9

What are behavioural adaptations?

Answer 9

What is an organism at that increases its chance of survival for reproduction?

Question 10

What are physiological adaptations?

Answer 10

Processes inside an organism’s body that increase its chance of survival

Question 11

What are anatomical adaptations?

Answer 11

Structural features of an organism’s body but increase its chance of survival