Question

The example of ocean and lake stickleback fishes indicates that morphology can be altered

A. by environmental factors (in this case, pollution).
B. by the elimination of a gene (Pitx1) from a population, which leads to loss of the trait (body armor and spines).
C. by altering the expression of a developmental gene in some parts of the body but not others.
D. only by changing the sequences of protein-coding genes.

Answer 1

The correct answer is option c. Morphology of stickleback fishes can be altered by changing the expression of developmental genes in response to environmental factors, influencing the evolution of populations and leading to changes in speciation rates.

Step-by-step explanation:

The example of ocean and lake stickleback fishes indicates that morphology can be altered by altering the expression of a developmental gene in some parts of the body but not others (C). This is supported by the information provided, which highlights how environmental factors can influence the evolution of populations and their physical traits.

Factors such as different feeding habits, sun exposure, or temperature during egg incubation can lead to phenotypic changes without necessarily changing the sequences of protein-coding genes. Adaptations to environmental conditions can result in a change in speciation rate as organisms undergo natural selection due to the new stimuli or challenges they face.