Key Area 7: Speciation

Question 1

What is a species?

Answer 1

A species is a group of organisms that are able to interbreed with each other and produce fertile offspring

Question 2

What is speciation?

Answer 2

Speciation is the formation of new biological species from one or a few original species

Question 3

What are the three factors contributing to speciation?

Answer 3

• isolation
• mutations
• selection

Question 4

Describe isolation factors

Answer 4

Two gene pools become separated by a barrier and are unable to successfully mate with each other

Question 5

Describe mutation factors

Answer 5

Beneficial mutations that occur within on sub-population will be different than the other sub-population which results in new variations arising within both groups.

Question 6

Describe selection factors

Answer 6

Each sub-population will have different desirable alleles best suited to the environment

Question 7

Name the three isolation barriers

Answer 7

• geographical barrier
• behavioural/reproductive barrier
• ecological barrier

Question 8

What is allopatric speciation?

Answer 8

When gene flow between populations is prevented by a geographical barrier

Question 9

What is sympatric speciation?

Answer 9

When two or more populations live close to each other in the same environment yet they become genetically isolated due to a behavioural or ecological barrier

Question 10

What is a hybrid zone?

Answer 10

A region occupied by several populations of an organism that can interbreed with each other