Diversity and Adaptation

Question 1

What is genetic diversity?

Answer 1

The number of different alleles in a population.

Question 2

What is the genome?

Answer 2

The entire genetic makeup of an organism.

Question 3

How do mutations increase genetic diversity?

Answer 3

They increase the number of alleles in the gene pool.

Question 4

What is natural selection?

Answer 4

Where fitter animals survive, reproduce and pass on genes while weaker animals die out, removing weaker genes from the gene pool.

Question 5

What is a gene pool?

Answer 5

All of the different genes present in a population.

Question 6

What is gene flow?

Answer 6

Introduction of new alleles from another population.

Question 7

Name 2 ways that genetic diversity could be reduced by.

Answer 7

Bottle necking
The founder effect

Question 8

What is bottle necking?
How does it effect the gene pool?

Answer 8

Where a chance event removes an allele from a population, causing a large proportion of the population to die. This reduces the number of genes in the gene pool.

Question 9

Give an example of an event that could lead to bottle necking.

Answer 9

New pathogen.

Question 10

What is the founder effect?

Answer 10

Where a small group of organisms split from the main population and colonise a new region. This creates a new population with a much smaller gene pool.

Question 11

What is genetic drift?

Answer 11

Where there is a gradual change in allele frequency due to natural selection/chance in a population.

Question 12

How can natural selection benefit animals?

Answer 12

It ensures that only the most advantageous alleles are passed onto future generations.

Question 13

Why can random mutation benefit alleles?

Answer 13

It can cause changes to genes that increase organism survival more.

Question 14

What are selection pressures?

Answer 14

Environmental factors the affect the chance of survival.

Question 15

Name 2 types of selection.

Answer 15

Stabilising
Directional

Question 16

What is stabilising selection?

Answer 16

Where allele frequencies are kept constant over many generations until a change in environment occurs.

Question 17

Explain an example of stabilising selection.

Answer 17

For example, very high and very low human birthweights are selected against, which ensures that average, healthy birthweights are most common.

Question 18

Describe the shape of a distribution curve showing stabilising selection.

Answer 18

Bell shape curve.

Question 19

What is directional selection?

Answer 19

A change in environment/selection pressure causes a gradual shift in allele frequency over time.

Question 20

Explain an example of directional selection.

Answer 20

Presence of antibiotics in the body acts as a selection pressure so mutations in bacteria start to occur randomly. These mutations can be beneficial for the bacteria as it allows them to survive in an environment containing antibiotics.

Question 21

Describe the shape of a graph representing directional selection.

Answer 21

Directional selection favours one phenotype causing the mean frequency of the allele to shift. A previously uncommon allele may start to be selected, so the graph shifts to the left or right.

Question 22

What are anatomical adaptations?

Answer 22

Structural/physical features.

Question 23

What are physiological adaptations?

Answer 23

Adaptations that alter biological processes in the body.

Question 24

What are behavioural adaptations?

Answer 24

Change how organisms act in environments to increase chance of survival.