Question

Scientists have discovered homeotic genes in many kinds of organisms, including fruit flies, mice, and humans. These homeotic genes regulate gene expression and control patterns of development in specific regions of young embryos. Molecular biologists have learned that homeotic genes share a very similar nucleotide sequence, which controls the development of similar portions of fly and mouse embryos. They have found a similar set of genes in humans, which also control corresponding regions of the developing human embryo.
Which of the following statements summarizes a conclusion based upon the evidence contributed by molecular biologists?

Homeotic Genetics

A.
Patterns of development among different animal species did not evolve from a common ancestor.
B.
Humans evolved from flies.
C.
Similar patterns of development increase an organism’s likelihood of surviving and reproducing.
D.
Fruit flies, mice, and humans provide evidence of divergent evolution.

Answer 1

Answer:

D

Explanation:

The presence of homeotic genes shows that all of the listed organisms (mice, flies, humans etc) all evolved from a common ancestor.

(A) is wrong as the evidence of the same gene existing in vastly different species shows the evolutionary relationship between these organisms.

(B) is wrong as there is insufficient evidence to prove that flies are the precessor of humans. We do know that flies and humans have evolved from a common ancestor though.

(C) is non-conclusive as the passage said nothing about the gene allowing the species to have a higher chance of surviving and reproducing. Hence, an errornous claim.

(D) is the correct answer as from a common ancestor, all of the listed organisms undergo and accumulates mutation, undergoes selective pressures that resulted in divergent evolution (aka branching evolution that results in many noval species forming) after millions of years.