Evolution

Question 1

What is the gene pool?

Answer 1

Sum of all genetic material within a population at a particular time.

Question 2

What does a large gene pool have?

Answer 2

Increased genetic diversity.

Therefore, the population will be better able to withstand selection pressures.

Question 3

What are changes in allele frequency usually caused by?

Answer 3

Gene flow

Question 4

What is gene flow?

Answer 4

The movement of genetic information between populations.

Question 5

What are two primary mechanisms of gene flow?

Answer 5

Immigration - introducing alleles

Emigration - removing alleles

Question 6

What are barriers to gene flow?

Answer 6

Geographical

• oceans
• mountains
• lakes
• deserts
• ice sheets

Sociocultural

• economic status
• educational attainment
• religion
• language

Question 7

What is genetic drift?

Answer 7

The occurrence of characteristics in a population due to chance instead of natural selection.

Can play a large role in evolution in small populations.

Question 8

What is the founder effect?

Answer 8

When a new population is formed by a small number of people.
This means that the new population may not reflect the allele frequency of the original population.

Can lead to decreased genetic diversity.

Question 9

What is the bottleneck effect?

Answer 9

When a population’s size suddenly decreases, usually due to a natural disaster.
The allele frequency of the population post-disaster may not be reflective of the allele frequency of the pre-disaster population.

Question 10

What are the steps of speciation?

Answer 10

1) Variation
There is variation between individuals in the species

2) Isolation
Populations of the same species are isolated with no gene flow between populations

3) Selection
Isolated populations are subjected to different selection pressures

4) Speciation
Allele frequencies change, eventually becoming so different that the different populations are unable to interbreed