4.4 Genetic Diversity and Adaptation

Question 1

What is genetic diversity?

Answer 1

The total number of different alleles within a population

Question 2

What is a gene pool?

Answer 2

The total number of all alleles of all the individuals in a population at a set time

Question 3

What is allele frequency?

Answer 3

The proportions of the different alleles in the gene pool

Question 4

What is population?

Answer 4

Group of individuals of the same species that live in the same place

Question 5

What is a species?

Answer 5

Individuals that can interbreed to produce fertile offspring

Question 6

What is an allele?

Answer 6

Different forms of a gene

Question 7

What is natural selection?

Answer 7

The natural process of stronger alleles surviving because they are better adapted to their environment
Therefore breeding which increases the frequency of those advantageous alleles in the next generation

Question 8

What is reproductive success?

Answer 8

Successfully producing fertile offspring

Question 9

What is fitness?

Answer 9

Ones that survive to reproduce

Question 10

Why is having a greater genetic diversity in a population better for its chance of survival?

Answer 10

More variety = more alleles in the population

Therefore with environmental change one individual may have an allele that would allow them to survive

Question 11

What can happen to populations with a low genetic diversity?

Answer 11

They are very vulnerable

Can lead to a genetic bottleneck eg cheetahs

Question 12

What changes allelic frequency in a population over time?

Answer 12

Natural selection
Survival of the fittest

As environmental change leads to selection and advantageous alleles survive to reproduce

Therefore allele frequencies will change and only some are passed to the next generation

Question 13

What decides if an allele is advantageous?

Answer 13

Depends on the environmental conditions at any one time

Question 14

What are the stages of natural selection?

Answer 14

Variation
Mutation
Environmental change 
Competition 
Survival
Reproduction 
Alleles

Question 15

What pneumonic helps remember natural selection?

Answer 15

Very
Massive
Eagles
Can 
Soar
Really
Aggressively

Question 16

What are the types of selection?

Answer 16

Directional
Stabilising
Disruptive

Question 17

What is directional selection?

Answer 17

Selection that favours a phenotype best suited to a changing environment at one extreme of the population

This results in changes to the characteristics of a population as these individuals are more likely to survive and breed - pass on their alleles

The ‘mean’ will therefore shift

Question 18

What is stabilising selection?

Answer 18

Selection against both extremes (eliminating extreme phenotypes) associated with non-changing/stable environments over many years

Those closest to the mean are more likely to pass their alleles on - maintaining favourable characteristics = a successful species

The range and distribution becomes smaller and narrower

Question 19

What is a normal distribution?

Answer 19

A bell shaped curve produced when a certain distribution is plotted on a graph

Question 20

What is an example of directional selection?

Answer 20

Antibiotic resistance

The bacterium that were resistant survived to reproduce
Therefore their population became greater than the non-resistant bacteria

Question 21

What is an example of stabilising selection?

Answer 21

Birth mass of babies

The mortality rate of babies is high at the two extremes of very underweight and very overweight

Question 22

What are the types of adaptations from natural selection?

Answer 22

Anatomical
- short ears, thick fur

Physiological
- different biomolecules as sources of energy

Behavioural
- migration of swallows