NEET BIOLOGY

Detailed explanation-1: -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-2: -Comparative Embryology 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.

Detailed explanation-3: -Similarities in structure among distantly related species are analogous if they evolved independently in similar environments. They provide good evidence for natural selection. Examples of evidence from embryology which supports common ancestry include the tail and gill slits present in all early vertebrate embryos.

Detailed explanation-4: -These likenesses in structure, called homologies, are the result of descent from a common ancestor. In related species, the same anatomical features evolved into distinct forms as they were used in different environments or for different functions.

Detailed explanation-5: -Similar anatomy across different species highlights their common origin and can be seen in homologous and vestigial structures. Embryology provides evidence for evolution since the embryonic forms of divergent groups are extremely similar.