Comparative anatomy is used to determine the relationships between species but also to study the anatomy of different species. This allows links to be made between species and thus determine common ancestors between creatures that may seem to have varied descendants. Paleo-biologists use similar characteristics of any fossil to trace common ancestry and find out how different groups are related to each other. The most convincing evidence of these fossil relationships are transitional fossils. Comparative anatomy also allows the study of evolution within a creature and how they have developed due to the adapting to different environments. Organisms with similar structures, were concluded to have come from a common ancestor. In today's society, comparative anatomy can serve as the first line of reasoning in determining the relatedness of species. Darwin had already used fossils to compare the anatomy of several species long before the discovery of DNA.
Homologous and Analogous Traits
A major problem in determining evolutionary relationships based on comparative anatomy can be seen when we look at wings. Wings are present in a number of very different groups of organisms. Birds, bats and insects all have wings, and it is easy to conclude that the three groups must have had a common winged ancestor. However, the wings of bats and birds are both derived from the forelimb of a common, probably wingless, ancestor. Both have wings with bone structures similar to the forelimbs of four-legged, animals. Traits that are derived from a trait found in a common ancestor are called homologous traits. Studying bird wings and insect wings, it is noticeable that the bird wing has bones inside and is covered with feathers, while the dragonfly wing is missing both of these structures. A trait that has developed independently in two groups of organisms from unrelated ancestral traits are called analogous.
We can look at similar species today and compare their structures. Take, for example deers, moose, zebra and horses. They share a similar body structure, but deers and moose have antlers and zebras and horses don’t. The reason for that is because deers and moose live alone they need to be able to protect themselves from predators while zebras and horses live in large herds which provide protection from predators since it’s easier to attack an individual than a huge herd. Also, grazing or running with antlers is much harder to do in a herd. This supports the theory of Natural Selection.
In today's society, comparative anatomy is commonly used in the field of paleontology but also phylogeny, the evolutionary development of the human race. So while anatomical evidence for evolution was the first and most famous method, it is not the most useful. It was important because it provided the first hard evidence for evolution, but it is extremely dependent on having the right conditions to form the fossil, making it impossible to form a complete and accurate fossil record. So while comparing anatomical structures of species is the most notable method of proving evolution and tracing ancestry, it is not as useful and accurate as DNA evidence. It is, however, the most important method as it was the one that first opened the door to evolution.
Homologous and Analogous Traits
A major problem in determining evolutionary relationships based on comparative anatomy can be seen when we look at wings. Wings are present in a number of very different groups of organisms. Birds, bats and insects all have wings, and it is easy to conclude that the three groups must have had a common winged ancestor. However, the wings of bats and birds are both derived from the forelimb of a common, probably wingless, ancestor. Both have wings with bone structures similar to the forelimbs of four-legged, animals. Traits that are derived from a trait found in a common ancestor are called homologous traits. Studying bird wings and insect wings, it is noticeable that the bird wing has bones inside and is covered with feathers, while the dragonfly wing is missing both of these structures. A trait that has developed independently in two groups of organisms from unrelated ancestral traits are called analogous.
We can look at similar species today and compare their structures. Take, for example deers, moose, zebra and horses. They share a similar body structure, but deers and moose have antlers and zebras and horses don’t. The reason for that is because deers and moose live alone they need to be able to protect themselves from predators while zebras and horses live in large herds which provide protection from predators since it’s easier to attack an individual than a huge herd. Also, grazing or running with antlers is much harder to do in a herd. This supports the theory of Natural Selection.
In today's society, comparative anatomy is commonly used in the field of paleontology but also phylogeny, the evolutionary development of the human race. So while anatomical evidence for evolution was the first and most famous method, it is not the most useful. It was important because it provided the first hard evidence for evolution, but it is extremely dependent on having the right conditions to form the fossil, making it impossible to form a complete and accurate fossil record. So while comparing anatomical structures of species is the most notable method of proving evolution and tracing ancestry, it is not as useful and accurate as DNA evidence. It is, however, the most important method as it was the one that first opened the door to evolution.