Topic 6c- Speciation / natural selection

Question 1

What is a species?

Answer 1

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

Question 2

What is speciation?

Answer 2

Speciation is the development of a new species. Speciation occurs when populations of the species become so different that they can no longer succesfully interbreed to produce fertile offspring.

Question 3

What is isolation (in terms of speciation)

Answer 3

Isolation is where populations of a species become separated due to a physical barrier (e.g. a flood or an earthquake that geologically isolate some individuals from the main population.)

Question 4

How does speciation occur?

Answer 4

1. A physical barrier isolates populations of a species
2. Each population shows genetic variation because they have a wide range of alleles
3. Individuals in each population have characteristics that are more beneficial for survival and so are more likely to breed successfully
4. The alleles that control the beneficial characteristics are more likely to be carried on to the next generation
5. The two populations are under different environments in which different alleles are beneficial
6. The populations become so different that they can no longer interbreed to produce fertile offspring and therefore a new species has formed

Question 5

Who worked with Darwin on natural selection?

Answer 5

Alfred Russel Wallace

Question 6

What did Wallace study and give examples of eventually?

Answer 6

He looked at warning colours used by butterflies to deter predators and from this concluded on natural selection and the concept of speciation.