Elephants are not the most common species in African grasslands. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands convert to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the following describes why elephants are the keystone species in this scenario?

#Question id: 3286

#Unit 9. Evolution & Diversity of Life Forms

 In a human population, the gene frequencies of the alleles for the ABO system are as follows:

A = 29%                         B = 7%                                    0=64%

Assuming complete random mating and Hardy-Weinberg equilibrium,

What are the blood type A frequencies in this population?

#Question id: 3287

#Unit 9. Evolution & Diversity of Life Forms

Which statement is not an assumption of the Hardy–Weinberg law?

a. The allelic frequencies (p and q) are equal.

b. The population is randomly mating.

c. The population is large.

d. Locus is di-allelic

#Question id: 3288

#Unit 9. Evolution & Diversity of Life Forms

Migration causes changes in the allelic frequency of a population by introducing alleles from other populations. The magnitude of change due to migration depends on

#Question id: 3289

#Unit 9. Evolution & Diversity of Life Forms

If, someday, an archaean cell is discovered whose SSU-rRNA sequence is more similar to that of humans than the sequence of mouse SSU-rRNA is to that of humans, the best explanation for this apparent discrepancy would be

#Question id: 3290

#Unit 9. Evolution & Diversity of Life Forms

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?

#Question id: 3291

#Unit 9. Evolution & Diversity of Life Forms

Which of the following is the most predictable outcome of increased gene flow between two populations?