ANATOMY

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 If two or more species share a unique physical trait they may all have inherited this trait from a common ancestor. Traits that are shared due to common ancestry are homologous structures. The similar bone arrangement of the human, bird, and whale forelimb is a structural homology.

Detailed explanation-3: -In genetics, homology is measured by comparing protein or DNA sequences. Homologous gene sequences share a high similarity, supporting the hypothesis that they share a common ancestor. Homology can also be partial: new structures can evolve through the combination of developmental pathways or parts of them.

Detailed explanation-4: -If different species share common ancestors, we would expect organisms to share similarities inherited from those ancestors. Features inherited from common ancestors-even if their appearance is quite different in close relatives-are known as homologies.