A. Describe how embryological similarities across vertebrate species give some evidence of those species having descended from a common ancestor.
A. There is a popular belief among developmental biologists that "Ontogeny recapitulates phylogeny." This means that as an embryo develops it progresses through stages that are similar to an ancestral form. By examining embryogenesis of various species of vertebrates one can establish similarlities between traits that were derived from a common ancestor. A classic image drawn by Haeckel notes the similarities between embryonic stages of fish, salamander, tortoise, chick, hog, calf, rabbit and human. Each of these diverse species have embryonic stages with similar features such as gills (in the case of humans pharygneal arches have been proposed to resemble primitive gill slits), ...
Paragraph answers with web references to answer two questions regarding evolution.