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. Identify the key concept: The question is about the similarity of DNA sequences in different species and its implications for evolutionary biology.
2. Understand the options: Each option proposes a different relationship between DNA sequence similarity and species relatedness or evolutionary theory.
3. Analyze the options in relation to basic genetic principles: DNA sequences tend to be more similar among closely related species due to shared ancestry and less time for mutations to accumulate.
4. Consider the concept of common descent: This principle suggests that all organisms share a common ancestor, and thus, DNA sequences can provide evidence supporting this theory if they show patterns of similarity consistent with the evolutionary relationships.
5. Evaluate the options based on evolutionary biology: Determine which options are supported by the understanding that DNA sequence similarity varies with the degree of relatedness among species and can provide evidence for common descent.

Key Concepts

DNA Sequence Conservation

DNA sequences can be conserved across different species, particularly for essential genes. This conservation indicates that these sequences have remained relatively unchanged throughout evolution, suggesting their importance in biological functions. The degree of conservation often correlates with the evolutionary relationship between species.

Phylogenetic Relationships

Phylogenetics is the study of evolutionary relationships among biological species based on similarities and differences in their physical or genetic characteristics. Closely related species tend to have more similar DNA sequences, while distantly related species exhibit greater differences, reflecting their divergence over time.

Common Descent

The hypothesis of common descent posits that all living organisms share a common ancestor. This concept is supported by genetic evidence, as similarities in DNA sequences among different species can indicate shared ancestry. The more closely related two species are, the more similar their DNA sequences will be, reinforcing the idea of common descent.