Comparative Anatomy The study of similarities and differences anatomy of different species.
The study of body structures of different animal species for the purpose of understanding adaptive changes that these species have undergone throughout the course of evolution from a common ancestor. Comparative anatomy is seen when homologous structures appear in very different species, where the structure has a similar appearance but a different function. This concept of the observation of similarities in bodily structure (particularly focusing on vertebrates thus far) has been used as evidence for evolution since up to 300 year pre-Darwinian times.
Homologous structures are anatomical structures that appear in different species, exemplifying anatomical commonalities possibly demonstrating descent from a common ancestor.
An example of comparative anatomy is the similarity between felines (cats), cetaceans (porpoises), chiroptera (bats) and homo sapiens (humans), all demonstrate the presence of phalanges, metacarpal, carpal, ulna, radius and humerus bones, found in the front/upper limbs. Which shows a correlation between them, and this may relate to these species having a common ancestor, therefore coinciding with theory of evolution.
Darwin used the prevalence of comparative anatomy across numerous species to support his theory of evolution. However in the early 19th century, Baron Richard Cuvier argued that an animals' structural and functional characteristics related more to their interaction with their environment, and opposed Darwin's theory of evolution. Though technically Cuvier's theory does not completely disregard the theory of evolution from a common ancestor, as in order for an adaptive change of a species to occur the species must interact with their environment. Hence why bats fly, whales swim, cats walk and humans grip things with the same homologous structures. Each fills a different niche in a different environment, upper canopy, water, land (four and two-legged) respectively.
An example of similar bodily structures appearing in different species that is not an example of comparative anatomy is the similarity in wing structure of birds and bats in comparison to flying insects. This is because the wing structure has the same function and these two groups of species do not descend from a common ancestor, (therefore this structure is an analogous structure).
Comparative anatomy also coincides with palaeontology, which provides evidence of now extinct species providing the basis for the homologous structures seen in modern-day species. For example the archaeopteryx, a transitional fossil that shows the connection between non-avion dinosaurs and birds.
Hayley, Natasha, Georgie and Amy