Commonly called gross anatomy, macroscopic anatomy involves studying the structures and forms which can be seen on organism with the naked eye. The type of organism does not matter. A botanist may study the macroscopic anatomy of a plant, such as the shape and size of its leaves. A doctor might study the proportions of his patients, measuring their weight and height. Both of these scientists are using skills of gross anatomy.
Many branches of biology use gross anatomy to evaluate their subjects. While this is often combined with microscopic anatomy and physiology, sometimes the macroscopic anatomy is the only observable system. This definitely true of archeology and evolutionary biology. Both of these branches of biology use evidence from the fossil record to establish relationships between extinct animals. Soft tissue does not often fossilize, thus these scientists must have a comprehensive knowledge of skeletal anatomy. Different species and fossils can be compared using comparative anatomy, which recognizes similarities between specimens.
For instance, a scientist using comparative anatomy could hypothesize the evolutionary relationships between a bat, a blackbird, and an ostrich. At first glance, the blackbird and the bat may be more related based upon size. But the scientist would quickly notice that the bat is covered in hair, while the blackbird has feathers. Upon examination of the wings and their bones, the scientist would find that the bat wing resembles an outstretched hand, while the blackbird bones have fused into a large bone that extends the length of the wing, with the feathers and skin supporting the rest of the wing. Even though the ostrich cannot use its wings to fly, the structure of the bones are the same. They might be different sizes, but it is clear that the blackbird and ostrich are more closely related to each other than either is related to the bat. This simple exercise in gross anatomy provides the basis of the classification of many organisms.
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