Extinction And Speciation

Question 1

For what six reasons do species become extinct?

Answer 1

1) environment changes too quickly
2) a new predator kills them
3) a new disease kills them
4) they can’t compete with another species for food
5) a catastrophic event happens that kills them all
6) a new species develops (speciation)

Question 2

What is a species?

Answer 2

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

Question 3

What is speciation?

Answer 3

Thé development of new offspring

Question 4

When does speciation occur?

Answer 4

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

Question 5

What two things lead to speciation?

Answer 5

Natural selection

Isolation

Question 6

What is isolation?

Answer 6

Where populations of species are separated

Question 7

Why does isolation happen?

Answer 7

Due to a physical barrier e.g. Floods and earthquakes can cause geological barriers that isolate individuals from the main population

Conditions on either side of the barrier will be different so different characteristics will become more common in each population due to natural selection

Question 8

What is natural selection?

Answer 8

Each population shows variation because they have a wide range of alleles

In each population individuals with characteristics that make them better adapted to their environment have a better chance of surviving so are more likely to successfully breed

Allèles that control the beneficial characteristic are more likely to be passed on to the next generation

Question 9

What happens when the different populations have changed? Yeh

Answer 9

They won’t be able to breed to produce fertile offspring so the two groups have become different species