Question

Biology 2.3.2

Question 2: Speciation

A booby is a type of seabird that lives in warm coastal environments. Boobies hunt ocean fish and make nests on shore. The booby has the unusual characteristic that its feet are bright blue, while the rest of its body is gray and black.

Suppose a population of boobies becomes separated after a flood creates a major water barrier across the island. One group is very large (N = 1000) while the other group is very small (N = 25). The conditions on the two islands are quite different including the presence of many more predators on the island with the larger population. Neither predators nor boobies can move between the islands.

a) Describe the necessary factors for speciation to occur within the booby population. Explain how the researchers would know that speciation did occur.

b) Describe the mechanism that would drive speciation in the big population. Explain how the mechanism would function differently in the small population.

c) Compare the gene frequencies of the two groups of boobies just after the flood. Explain any differences that will occur in the 20 years following the flood.

d) Fifty years after the flood, a biologist visits the islands and observes that the two groups of boobies are about the same size in population (about 1000), but one group has blue feet while the other group has red feet. Compare the gene frequencies of the two groups of boobies fifty years after the flood. Explain any differences.

e) Describe two tests that the biologist could run to determine whether the two groups are still the same species or not.

Answer 1

A) First we should know the meaning of speciation. It can be defined as emergence of new species through evolution. The Speciation occurs in the Island with larger population. Since, many predators are present in that Island. Booby's should shoe structural and genetical changes to survive against the attacks of the predators.

Researchers would come to know about speciation through phenotypic changes i.e bright blue feet, grey/black colour body changes with due course of time.

B) As explained in previous answer. Due to threat from predators, evolutionary changes are signidsigni in large population. Whereas in small population, it takes more time to evolve into a new species.

C)Gene frequencies are constant untill there is no migration, Mutation, genetic drift etc. In this case the smaller population, there is a low possibility for migration and Mutation.G ene frequency remains constant. Whereas in larger population Gene frequencies may become random after 20 years.

D) blue feet boobies are belongs smaller population. Because, Gene frequency remains constant in small population. WgereWh red feet boobies belongs to large population as they are in process of evolution due to the threat from predators.

E) by comparing external characters and DNA sequences, Polymerase Chain Reaction(PCR) technique.