Birds

Birds are phylogenetically considered to be members of the theropod dinosaurs; their closest non-avian relatives are the dromaeosaurid theropods. The first known fossil bird is Archaeopteryx, from the late Jurassic of Bavaria, Germany, which is represented by seven skeletons and a feather. There is no fossil evidence from before this time that has been proven to be of avian origin. The fossil record of modern birds began in the early Tertiary (Padian et al., 1998).

There are a lot of anatomical terms used to describe the evolution of birds, therefore diagrams showing the skeletons of a theropod dinosaur, Archaeopteryx and a modern bird are shown

Consider for a minute the diversity of birds. There are nearly 10,000 species! Is it possible to trace these birds back to one common ancestor, and if so, who is it.

One of the major criticisims of Darwin's Origin of Species was the apparent lack of any evidence showing the evolution of birds. Then, as luck might have it, only two years after he first published his book Archaeopteryx appeared.

Today there are 8 preserved fossils of Archaeopteryx in various museums of the world. What an amazing find for since though as it stirred scientists to try and figure out how birds were related to other creatures.

Archaeopteryx was amazing for a few reasons. First it looked like a dinosaur. Infact, except for the feathers and the fact that it had a wishbone it didn't really look like a bird. The jaws had teeth in them, of which no bird today has teeth. Clearly this bird had features of dinosarus AND birds. So where did birds evolve?

| Bird Evolution | |

| | |

| | |

| | |

| | |

| | | | | |

This family tree is not a chronological progression. Rather, it illustrates how evolution incorporates traits that evolved for unrelated reasons into a novel structure -- the wing of a bird. The skeletal adaptations that gave theropod dinosaurs an advantage of better balance or a swift strike to capture...