AP BIOLOGY

Detailed explanation-1: -DNA sequences are often used to determine relationships between organisms. DNA sequences that code for a particular gene can vary, though organisms that are closely related will have very similar sequences.

Detailed explanation-2: -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-3: -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, both alive and extinct, are related to each other.

Detailed explanation-4: -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.