'Comparative anatomy' is the study of similarities and differences in the
anatomy of
organisms. It is closely related to
evolutionary biology and
phylogeny (the
evolution of species).
Two major concepts of comparative anatomy are:
#
Homologous structures - structures (body parts/anatomy) which are similar in different species because the species have
common descent. They may or may not perform the same function. An example is the forelimb structure shared by
cats and
whales.
#
Analogous structures - structures which are similar in different organisms because they evolved in a ''similar environment'', rather than were inherited from a recent common ancestor. They usually serve the same or similar purposes. An example is the torpedo body shape of
porpoises and
sharks. It evolved in a water environment, but the animals have different ancestors.
The rules for development of ''special'' characteristics which differ significantly from general homology were listed by
Karl Ernst von Baer (the Baer laws).
History
Edward Tyson is regarded as the founder of comparative anatomy. He is credited with determining that marine mammals are, in fact, mammals. Also, he concluded that
chimpanzees are more similar to humans than to
monkeys because of their arms.
See also
★
Cladistics
★
Phylogenetics