Question

1. dolphins and sharks have streamlined body structures, making both animals well adapted for life in a marine environment. this common trait is best explained by which of the following? marks : 1.00 b. genetic drift. c. convergent evolution. e. founder effect. d. stabilizing selection. a. mimicry.

Explanation:

• Option A (Mimicry): Mimicry is when one species evolves to resemble another for protection or other benefits (e.g., Batesian mimicry where a harmless species mimics a harmful one). Dolphins and sharks having a streamlined body is not about one mimicking the other for such purposes, so A is incorrect.
• Option B (Genetic drift): Genetic drift is random changes in allele frequencies in a population, often in small populations. It doesn't explain the development of a similar adaptive trait (streamlined body) in two different species due to environmental pressure, so B is incorrect.
• Option C (Convergent evolution): Convergent evolution occurs when unrelated species independently evolve similar traits because they adapt to similar environments or ecological niches. Dolphins (mammals) and sharks (fish) are unrelated but both live in marine environments, so they evolved streamlined bodies (an adaptation for efficient movement in water) independently. This matches the scenario, so C is correct.
• Option D (Stabilizing selection): Stabilizing selection favors intermediate phenotypes and reduces variation, acting on a single population. It doesn't explain the similarity between two different species, so D is incorrect.
• Option E (Founder effect): The founder effect is a type of genetic drift where a new population is established by a small number of individuals, leading to reduced genetic variation. It has no relation to the evolution of similar traits in different species, so E is incorrect.

Answer:

C. Convergent evolution.