Speciation-the evolution of new species

Question 1

What is speciation?

Answer 1

The formation of new species.

Question 2

What are the factors required for two populations of the same species to evolve into two different species?

Answer 2

1. Reproductive isolation: any genetic changes will move into both populations eventually.
2. Genetic divergence: Genes must change via new mutations or chromosomal abnormalities.

Question 3

What are the pre-zygotic isolating mechanisms? EX

Answer 3

1. Ecological isolation: individuals do not mate because they do not live in the same habitat.
2. Behavioural isolation: individuals do not mate because one sex does not display the right ritual.
3. Temporal isolation: they do not mate at the same time.
4. Mechanical isolation: sexual organs are not compatible.
5. Gamete incompatibility: sperm cannot fertilize the egg

Question 4

What are the post-zygotic isolating mechanisms? EX

Answer 4

1. Zygote mortality: when the zygote cannot survive due to gene combinations that are harmful to his health.
2. Hybrid fertility: Cannot reproduce

Question 5

What are the two ways speciation can happen? EX

Answer 5

1. Allopatric speciation: where two populations are geographically separated.
2. Sympatric speciation: when new species arise even though the two populations share the same geographical location.

Question 6

How is sympatric speciation possible?

Answer 6

1. From ecological isolation
2. From polyploid: plants only

Question 7

What is adaptive radiation?

Answer 7

When a new species move to a new ecosystem with many different habitats to adapt to.