The DNA sequence for the same gene found in several species of mammals_________.
a. Is identical among all species.
b. Is equally different between all pairs of mammal species.
c. Is more similar between closely related species than between distantly related species.
d. Provides evidence for the hypothesis of common descent
e. More than one of the above is correct.

Verified step by step guidance

1. Understand the concept of DNA sequence similarity: DNA sequences in genes are inherited and can accumulate mutations over time. Closely related species share a more recent common ancestor, so their DNA sequences are more similar compared to distantly related species.
2. Analyze the options: Option (a) states that the DNA sequence is identical among all species. This is incorrect because mutations and evolutionary divergence cause differences in DNA sequences over time.
3. Evaluate option (b): This option suggests that DNA differences are equal between all pairs of mammal species. This is also incorrect because evolutionary relationships determine the degree of similarity, with closer relatives having more similar sequences.
4. Consider option (c): This option states that DNA sequences are more similar between closely related species than between distantly related species. This is correct because closely related species share a more recent common ancestor, leading to fewer accumulated mutations.
5. Assess option (d) and (e): Option (d) is also correct because the similarity in DNA sequences across species supports the hypothesis of common descent. Therefore, the correct answer is (e), as more than one of the options (c and d) is correct.

Key Concepts

DNA Sequence Conservation

DNA sequences can be conserved across different species, particularly for essential genes. This conservation often reflects the evolutionary relationships among species, where closely related species tend to have more similar DNA sequences due to shared ancestry.

Phylogenetics

Phylogenetics is the study of evolutionary relationships among biological entities, often using DNA sequences to construct evolutionary trees. It helps in understanding how species are related and can indicate that closely related species will have more similar genetic sequences compared to those that are distantly related.

Common Descent

The hypothesis of common descent posits that all living organisms share a common ancestor. Evidence for this can be found in the similarities of DNA sequences across different species, supporting the idea that species diverged from a shared lineage over time.