Evolution 7.3, 7.4

Question 1

Explain Allopatric speciation

Answer 1

1. A population is separated by a geographical barrier
2. Variations occur due to mutations, different selection pressures
3. No gene flow, reproductive isolation
4. Different alleles past on, change in allele frequency
   5.Eventually after repeated process, populations cannot breed to produce fertile offspring

Question 2

Explain symatric speciation

Answer 2

1. No geographical barrier, a group of the same species living in the same space
2. An isolation factor occurs such as ecological separation, behaviour separation
3. No gene exchange, Respiration isolation
4. Selection pressures can change allele frequency
5. Can lead to the increase in one population and the decline of the other

Question 3

Wjhat is ecological separation?

Answer 3

When two different populations live in different environments within the same area

Question 4

Describe Succession

Answer 4

1. Hostile environment such as bare rock. Pioneer species such as lichen are adapted to survive in these conditions
2. Lichens die and decompose, soil thickens meaning moss can grow
3. Larger plants can move into the area as they require more water, soil deepens
   4.shrubs ferns and trees start to grow, becoming dominant and diversity increases
4. Tress grow and become dominant, climax community reached