Paleobiologists use similar characteristics of any fossil to trace common ancestry and look how different groups are related to each other. The most convincing evidence of these fossil relationships are transitional fossils. Darwin had already used fossils to compare the anatomy of several species long before the discovery of DNA.
What Darwin noticed during his travels was that fossils in the oldest layers are vastly different from species today, but the fossils in younger and younger layers started to resemble current existing species until they were almost identical. He also noticed that their structures tended to become more and more complex.
From this, Darwin concluded that species have not remained the same since the beginning of the earth and that they gradually change over time. He also noted that as new species arise, old species die out- he called this process Natural Selection, in which the new species are more evolved and more capable versions of their ancestors, and therefore, more likely to thrive.
The problem is that- according to Darwin’s theory of evolution which states that evolution takes place through minute changes over an extended period of time- most of the fossils discovered have extremely varied differences, with no common ancestor in sight. Therefore basing the entire research on fossil record isn’t very productive. It’s hard to prove that chicken are closely related to the dinosaurs without substantial DNA evidence as well.
Also, the fossil record is very incomplete due to the extremely lucky circumstances needed in order for a fossil to exist and still remain in identifiable condition.
Thankfully fossils aren’t the only way of comparing animal anatomies. 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.
Therefore using structural similarities to prove evolution is substantially easier and less time consuming however, a lot less accurate when it comes to plotting the closest ancestor. Once again, take the Tyrannosaurus Rex and the chicken. Most people assume crocodiles are the closest related ancestors because of their large reptilian appearance, but the closest ancestor is in fact, the chicken, and this was only proven through DNA evidence and the study of their molecular structures.
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.
What Darwin noticed during his travels was that fossils in the oldest layers are vastly different from species today, but the fossils in younger and younger layers started to resemble current existing species until they were almost identical. He also noticed that their structures tended to become more and more complex.
From this, Darwin concluded that species have not remained the same since the beginning of the earth and that they gradually change over time. He also noted that as new species arise, old species die out- he called this process Natural Selection, in which the new species are more evolved and more capable versions of their ancestors, and therefore, more likely to thrive.
The problem is that- according to Darwin’s theory of evolution which states that evolution takes place through minute changes over an extended period of time- most of the fossils discovered have extremely varied differences, with no common ancestor in sight. Therefore basing the entire research on fossil record isn’t very productive. It’s hard to prove that chicken are closely related to the dinosaurs without substantial DNA evidence as well.
Also, the fossil record is very incomplete due to the extremely lucky circumstances needed in order for a fossil to exist and still remain in identifiable condition.
Thankfully fossils aren’t the only way of comparing animal anatomies. 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.
Therefore using structural similarities to prove evolution is substantially easier and less time consuming however, a lot less accurate when it comes to plotting the closest ancestor. Once again, take the Tyrannosaurus Rex and the chicken. Most people assume crocodiles are the closest related ancestors because of their large reptilian appearance, but the closest ancestor is in fact, the chicken, and this was only proven through DNA evidence and the study of their molecular structures.
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.