Evolution And Speciation

Question 0

How does DNA support Darwin’s theory?

Answer 0

Prove adaptations (mutations) controlled and passed on by genes

Question 1

What are the 5 steps of Darwin’s theory of natural selection?

Answer 1

1. organisms have to compete for limited resources
2. Best adapted organisms live - survival of the fittest
3. Surviving organisms pass on successful adaptations to offspring
4. Less well adapted organisms less likely to survive and reproduce
5. Over time successful adaptations become more common - species evolves

Question 2

What is speciation?

Answer 2

Over time organisms change so much create new species

Question 3

What does reproductively isolated mean?

Answer 3

Populations of species change so much they can’t interbreed to produce fertile offspring

Question 4

Explain how reproductive isolation is caused by geographic isolation.

Answer 4

1. Physical barrier divides population, eg river changes course
2. Mutations create new features in different groups of organisms
3. Natural selection spreads features through populations
4. Conditions on each side of barrier are slightly different so developing features will be different
5. Eventually individuals from the 2 populations will be so different they won’t breed fertile offspring - separate species