Biology STAAR (State of Texas Assessments of Academic Readiness) Practice Test

What kind of evolution does the concept of homologous structures support?

1. Convergent evolution

2. Adaptive radiation

3. Divergent evolution

4. Artificial selection

The correct answer is: Divergent evolution

Homologous structures support the concept of divergent evolution because they illustrate how different species can evolve from a common ancestor while developing different functions and adaptations over time. These structures, which may have similar anatomical features but serve different purposes, highlight the idea that species adapt to their particular environments while retaining a common evolutionary background. For instance, the forelimbs of mammals, such as humans, whales, and bats, all share a similar underlying skeletal structure, which indicates that they have diverged from a common ancestor. This divergence leads to the formation of new species as they adapt to their specific ecological niches. In contrast, other concepts such as convergent evolution involve unrelated organisms developing similar traits due to similar environmental pressures, while adaptive radiation refers to an organism rapidly diversifying into a variety of forms to adapt to different environments. Artificial selection, on the other hand, is the process by which humans breed organisms for desired traits. Thus, the distinct characteristics of homologous structures firmly align with the idea of divergent evolution.