Question

2. Kevin is a member of an endangered species of large, flightless birds from the order Rheiformes that are native to South America. In the 1800s, intense hunting pressure from humans and habitat loss caused a drastic decline in population. (0.5 pt) What type of evolution has occurred in Kevin's species? a. b. (0.5 pt) In 2009, scientists discovered another population of Kevin's species! To prevent inbreeding, scientists moved some individuals from each population to the other population. What type of evolution are they facilitating?

Answer 1

a.

Bottleneck effect:

• The bottleneck effect results due to extreme condition of genetic drift.
• Bottleneck effect may be observed in relation to natural disasters like earthquakes, floods, fire, famine, or other catastrophic effect.
• This results in severe reduction in population size.
• There is selection of few alleles that results in survival of few individual in a population, while some alleles may be entirely eliminated or lost.
• Allele frequency changes, from the initial frequency.
• The reduced population size causes more effect by genetic drift.
• This leads to random selection of an allele, which is established in the population and increases its frequency, until the normal numbers are regained.

b. Immigration

• When a population or individuals from population migrate and interbreed with individuals of another geographic region, gene flow results. Immigration or emigration.
• Here uni-directional immigration, by stepping-stone model.