Genetic Diversity and Natural Selection 4B

Question 1

Define genetic diversity

Answer 1

the number of different alleles of genes in a species or population

Question 2

What increases genetic diversity

Answer 2

Mutations in the DNA - forming new alleles
Different alleles being introduced into a population when individuals from another population migrate into them and reproduce

Question 3

Define gene flow

Answer 3

Different alleles being introduced into a population when individuals from another population migrate into them and reproduce

Question 4

What process allows natural selection to occur

Answer 4

genetic diversity

Question 5

What effect does a genetic bottleneck have on genetic diversity

Answer 5

Causes a big reduction in genetic diversity, eg when a large number of organisms die within a population before reproducing

This reduces the number of different alleles in a gene pool so reduces genetic diversity

The survivors reproduce and a larger population is created from a few individuals

Question 6

Describe the founder effect

Answer 6

This is 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

The frequency of each allele in the new colony might be very different to the frequency of those alleles in the original population this may lead to a higher incidence of genetic disease

Founder effect can occur as a result of migration or geographic separation

Question 7

Natural selection process

Answer 7

Not all individuals are as likely to reproduce as each other, there’s differential reproductive success in a population, individuals that have an allele that increases their chances of survival are more likely to survive, reproduce and pass on their genes.

This means that a greater proportion of the next generation inherits the beneficial allele

They are more likely to survive, reproduce and pass on their genes

The frequency of the beneficial allele increases

The advantageous allele becomes more common

Question 8

Describe behavioural adaptations

Answer 8

Ways an organisms acts to increase its chances of survival and reproduction eg possums play dead when threatened by a predator

Question 9

Describe physiological adaptations

Answer 9

Processes inside an organisms body that increase its chances of survival eg brown bears hibernate over the winter and lower their metabolism, this conserves energy so they don’t need to look for food when it is scarce

Question 10

Describe anatomical adaptations

Answer 10

Structural features of an organisms body that increases its chance of survival , eg whales have a thick layer of blubber which keeps them warm in the cold sea