Through extensive research and investigation, scientists have determined that birds are the closest living relatives to dinosaurs. There are many characteristics that link dinosaurs to birds, most of which can be seen by comparing their anatomies and looking at fossils.
The bone structure of dinosaurs is very similar to that of birds. They both have elongated arms, clawed, three fingered hands and four toed feet and flexible wrist bones. Dinosaurs’ leg bones are also in an upright position, similar to birds and mammals, very different from the sprawling leg position of lizards.
The bone structure of dinosaurs is very similar to that of birds. They both have elongated arms, clawed, three fingered hands and four toed feet and flexible wrist bones. Dinosaurs’ leg bones are also in an upright position, similar to birds and mammals, very different from the sprawling leg position of lizards.
Another big piece of evidence is the Archaeopteryx, the oldest known bird. This fossil was first discovered in 1860 in Germany in limestone from the late Jurassic period. It was very unusual, as it appeared to be a mixture of a dinosaur and a bird. We now know that this an example of a transitional species, meaning it ”transitions” from dinosaur-like reptiles to birds. This was extremely important, because it provided a link in the evolutionary history of birds and showed that dinosaurs and birds are related.
One other reason we believe birds and dinosaurs are
closely related is because of their eggs. Both groups lay eggs that are fairly similar. They are hard-shelled, but they allow gases to easily pass through them. This is different from most of the other reptiles, as they have soft, leathery shells that are easier to break open. Many reptiles need this because they don’t have beaks, whereas most dinosaurs and birds do have beaks.
Despite the extensive evidence, there has been some controversy regarding the relationship between dinosaurs and birds. One issue that has been discussed is the lack of bird fossils between the Archaeopteryx and the dromaeosaurs, a group of birds from the Early Cretaceous period. This disregards the partial remains of dromaeosaurs from the Late Jurassic, as well as the fact that other species very similar to the dromaeosaurs existed in the Late Jurassic, so it is very likely that ancestors of the dromaeosaurs was also present during this time.
As their closest relative, dinosaurs would have to be evolved from birds if they were to come back, but we believe it is extremely unlikely that this would happen. Modern birds have adapted so they are better suited to the current environment. They are well suited to our industrialized, human populated world. Dinosaurs are not well suited to this environment. If
they were to evolve again, it is likely that they would be selected against because they would not survive as well as other birds, even if the climate can support them.
One other reason we believe birds and dinosaurs are
closely related is because of their eggs. Both groups lay eggs that are fairly similar. They are hard-shelled, but they allow gases to easily pass through them. This is different from most of the other reptiles, as they have soft, leathery shells that are easier to break open. Many reptiles need this because they don’t have beaks, whereas most dinosaurs and birds do have beaks.
Despite the extensive evidence, there has been some controversy regarding the relationship between dinosaurs and birds. One issue that has been discussed is the lack of bird fossils between the Archaeopteryx and the dromaeosaurs, a group of birds from the Early Cretaceous period. This disregards the partial remains of dromaeosaurs from the Late Jurassic, as well as the fact that other species very similar to the dromaeosaurs existed in the Late Jurassic, so it is very likely that ancestors of the dromaeosaurs was also present during this time.
As their closest relative, dinosaurs would have to be evolved from birds if they were to come back, but we believe it is extremely unlikely that this would happen. Modern birds have adapted so they are better suited to the current environment. They are well suited to our industrialized, human populated world. Dinosaurs are not well suited to this environment. If
they were to evolve again, it is likely that they would be selected against because they would not survive as well as other birds, even if the climate can support them.