AP BIOLOGY

Detailed explanation-1: -Because the DNA sequence determines a protein’s amino acid sequence, a gene shared by two closely related organisms should have similar, or even identical, amino acid sequences. That’s because closely related species most likely diverged from one another fairly recently in the evolutionary span.

Detailed explanation-2: -Proteins are made from amino acids and the sequence of these amino acids is controlled by genes. Comparing how many of the amino acids are in the same positions on the protein chain can provide some idea of how closely related two species are.

Detailed explanation-3: -Molecular clocks are used to determine how closely two species are related by calculating the number of differences between the species’ DNA sequences or amino acid sequences. These clocks are sometimes called gene clocks or evolutionary clocks.

Detailed explanation-4: -Similarities and differences among biological molecules (e.g., in the DNA sequence of genes) can be used to determine species’ relatedness. Biogeographical patterns provide clues about how species are related to each other.