Speciation

Question 1

Define speciation

Answer 1

The evolution of a species (which can reproduce to produce fertile offspring) branching from its ancestors in a phylogenetic tree and may result in the extinction of a previous species

Question 2

What is a hybrid?

Answer 2

The offspring of two organisms of different species

Question 3

Genetically, why are hybrids infertile?

Answer 3

Their gametes are haploid, but they might not be able to join with the gametes of another organism to produce a zygote with diploid cells

Question 4

What might result in the development of a new species?

Answer 4

• Founders effect

- Bottle-neck effect

Question 5

What is epistasis?

Answer 5

The interaction of genes that are not alleles, in particular, the suppression of the effect of one such gene by another

Question 6

What is allopatric speciation?

Answer 6

When a given group has been separated from the original group. Geographic isolation.

Question 7

What is sympatric speciation?

Answer 7

Speciation occurs even when the two groups are living in the same area. Genetic isolation.

Question 8

Suggest how two species may arise by sympatric speciation.

Answer 8

1. Occurs in the same habitat
2. Mutations cause different alleles
3. Reproductive isolation/ No gene flow/ Gene pools remain separate
4. Different alleles passed on/ Change in frequency of alleles
5. Disruptive selection
6. Eventually different species cannot reproduce
   to produce fertile offspring;

Question 9

What is a gene pool?

Answer 9

All alleles present within a population

Question 10

Explain how different subspecies may have evolved from a common ancestor (whose population had been separated).

Answer 10

1. No interbreeding due to geographical isolation
2. Mutation linked to different alleles
3. Selection for new alleles
4. increased reproductive success;
5. Change in allele frequency

Question 11

What is genetic drift?

Answer 11

The random change of the frequency of a particular allele