AP BIOLOGY

Detailed explanation-1: -Homologous structures provide evidence for common ancestry, while analogous structures show that similar selective pressures can produce similar adaptations (beneficial features). Similarities and differences among biological molecules (e.g., in the DNA sequence of genes) can be used to determine species’ relatedness.

Detailed explanation-2: -Homologous structures are structures that are similar in related organisms because they were inherited from a common ancestor.

Detailed explanation-3: -DNA and the genetic code reflect the shared ancestry of life. DNA comparisons can show how related species are.

Detailed explanation-4: -Similarities in embryos are likely to be evidence of common ancestry. All vertebrate embryos, for example, have gill slits and tails. All of the embryos in Figure 9.3. 4, except for fish, lose their gill slits by adulthood, and some of them also lose their tail.