Living Environment Regents Practice Test

Which of the following is an indicator of similar evolutionary traits among species?

1. Similar habitats and feeding behaviors

2. Different DNA sequences with no overlap

3. Similar overall size and shape

4. Shared amino acid sequences in proteins

The correct answer is: Shared amino acid sequences in proteins

The presence of shared amino acid sequences in proteins serves as a strong indicator of similar evolutionary traits among species because amino acids are the building blocks of proteins, which play essential roles in the functioning of living organisms. When species share amino acid sequences in their proteins, it often suggests that they have evolved from a common ancestor. The similarity in protein sequences reflects closely related genetic makeup, indicating that the species might possess similar biochemical pathways or functions due to their shared ancestry. This molecular evidence is crucial in evolutionary biology as it provides concrete data that can be compared across different species, helping to unveil their evolutionary relationships. In contrast, while similar habitats and feeding behaviors could indicate ecological relationships, they do not directly demonstrate a shared evolutionary path. Different DNA sequences with no overlap suggest divergent evolutionary paths rather than similar traits. Lastly, similar overall size and shape may arise from convergent evolution, where unrelated species develop similar traits due to experiencing similar environmental pressures, rather than reflecting a common ancestry.