Question

Which of the following statements about human population in wealthy countries is incorrect?

		life history is r-selected
		age distribution is relatively uniform
		average family size is relatively small
		the survivorship curve is Type I

The sickle-cell anemia allele is an example of the heterozygote advantage.

True

False

Which of the following is not a pre-zygotic reproductive barrier?

		hybrid sterility
		temporal isolation
		habitat isolation
		behavioral isolation

Answer 1

Ans 1.life history is r selected. This is incorrect about human population of wealthy countries . Actually they are k selected.

Ans 2 true. Sickle cell anaemia allele is an example of heterozygote advantage. Heterozygote advantage means those cases in which the heterozygous genotype has higher relative fitness either than homozygous recessive or dominant.

Ans 3 prezygotic barrier means prevent or stop fertilisation before its occurrence . Hybrid sterility is not a prezygotic reproductive barrier.