The evolution of birds is one of the great mysteries of science. The fossil record does not provide a complete picture of how these titans of nature got together and where they went. In this article, we will discuss some of the facts about the development of birds.
Unlike vertebrates, birds are composed of more than one body part. A pair of wings is the basic structure that together forms the body of a bird. Flies have only one set of paired wings, while ducks and whales have two. In the case of birds, the two wings are joined in a middle area called the cerebra. Along with their wings, birds have a tail, which has several limbs like claws and feathers. The arrangement of the different parts of the body is clearly evident in the shape of the head and the tail.
Birds Evolution – the Science Factor
Birds emerged from a bunch of meat-eating dinosaurs called theropods. That’s the very group that Tyrannosaurus rex belonged to, although birds evolved from small theropods, not enormous ones like T. rex. The oldest bird fossils are approximately 150 million years old.
As birds emerged and developed from these theropod dinosaurs, nature cleverly modified many of their features. However, it’s essential to remember that the animals were not “attempting” to be birds in any sense. The more closely we look, the more obvious it is that the suite of features that distinguish birds evolved through a complicated series of steps and worked different functions along the way.
Take their delicate feathers, for example. Small theropods related to Compsognathus perhaps evolved the first feathers. These hair-like, short feathers grew on their necks, heads, and bodies and presented insulation. The feathers seem to have had distinct color patterns as well, although whether these were for camouflage, display, species recognition, or another function is hard to tell.
As we have known, the first, hair-like delicate feathers obviously served an insulator function in birds. But in later theropods, such as oviraptorosaurs, the feathers on the hands and arms are long, even though the forelimbs are short. What did these mammals do with long feathers on short arms? One idea comes from some unusual fossils of oviraptorosaurs preserved in the Cretaceous sediments of the Gobi Desert. The animal skeleton is hunched up on an eggs nest, like a brooding chicken. The hands are scattered out over the eggs as if to protect them. So maybe these feathers served the function of warming the eggs and preserving and saving them from predators.
Evolution usually occurs at a scale far too slowly to be observed by humans. However, sadly the bird species are presently going extinct at a far higher rate than any potential speciation or other breeds of new species. The disappearance of a subspecies, population, or species represents the sad loss of a variety of genes.
