Question

Which of the following are considered to be essential parts of species formation (select all that are correct)

		The ancestral or starting species is in fact a reproductively isolated community (a single population)
		Barrier formation - subgroups are divided and isolated reproductively
		Divergence - different selection pressures operate on the divided subgroups producing different rates of success for various phenotypes
		If the barrier were to disappear (secondary contact) the groups would not be an interbreeding community - they have become genetically isolated from one another.
		Interbreeding and hybrid formation - some members of the divided groups find a way to meet and mate producing hybrids
		Barrier maintained in perpetuity - the barrier that initially divides the subgroups must be maintained over geological time in order for the new species to stay separate

Answer 1

Ans. Correct essential parts of species formation are-

Barrier formation - subgroups are divided and isolated reproductively

Divergence- different selection pressures operate on the divided subgroups producing different rates of success for various phenotypes.

Barrier maintained in perpetuity - the barrier that initially divides the subgroups must be maintained over geological time in order for the new species to stay separate.

Explanation: For new species to form, there should be isolation of sub-populations of an ancestral population and reproductive mating between the individuals in the two sub-populations is inhibited due to the physical barrier between the two sub-groups. Different selection pressures occur in the sub-groups and it leads to phenotypic difference. The barrier needs to be maintained for reproductive isolation so that there is no gene flow.