Speciation

Question 1

Define ‘speciation’

Answer 1

The development of a new species

Question 2

Define a ‘species’

Answer 2

A group of similar organisms that can reproduce to give fertile offspring

Question 3

When does speciation occur?

Answer 3

When populations of the same species become so different that they can no longer breed together to produce fertile offspring

Question 4

What 2 things lead to speciation?

Answer 4

1. Isolation
2. Natural selection

Question 5

Define ‘isolation’

Answer 5

Where populations of a species are separated

Question 6

What can cause isolation?

Answer 6

A physical barrier

Question 7

Gibe 2 examples of what can cause physical isolation, and how

Answer 7

1. Floods
2. Earthquakes

Can cause barriers that geographically isolate some individuals from the main population

Question 8

What on either side of a physical barrier might be slightly different? (plus examples)

Answer 8

Conditions e.g. different climates

Question 9

Because the environment is different on each side, different ____ will become more common in each population due to ____ ____

Answer 9

Because the environment is different on each side, different characteristics will become more common in each population due to natural selection

Question 10

Explain who natural selection causes different characteristics to appear in each population?

Answer 10

1. Each population shows variation because they have a wide range of alleles
2. In each population, individuals with characteristics that make them better adapted to their environment have a better chance of survival and so are more likely to breed successfully
3. So the alleles that control the beneficial characteristics are more likely to be passed on to the next generation

Question 11

Eventually, individuals from the different populations will have ____ so much that they won’t be able to ____ with one another to produce ____ offspring

Answer 11

Eventually, individuals from the different populations will have changed so much that they won’t be able to breed with one another to produce fertile offspring

Question 12

List the 4 basic steps to speciation

Answer 12

1. Two populations of the same species
2. Physical barrier separates them
3. Populations adapt to new environments
4. Development of new species

Question 13

So in summary:

Speciation happens when two or more populations of the same species ____ so much that they can no longer ____ ____ to produce ____ ____ . It can be caused by species becoming ____ from each other.

Answer 13

Speciation happens when two or more populations of the same species change so much that they can no longer breed together to produce fertile offspring. It can be caused by species becoming isolated from each other.