Evolution of birds: Research and Education


The fossil record of birds and their evolutionary history is not well documented. Birds are generally thought to have evolved from Maniraptora, a group of dinosaur theropods. Archaeopteryx, the first feathered animal fossil, was found about 150 million years ago in Upper Jurassic deposits. Archaeopteryx is regarded famously as the ' missing link ' between reptiles and modern birds. Bird fossils, as we know them, do not occur until 80-120 million years ago, the Cretaceous period. Some Mesozoic birds include the Enantiornithes, Ichthyornis (toothed seabirds), and Hesperornithiformes (primitive teeth flightless diving birds).

Birds dented and dinosaurs died at the end of the Cretaceous Period. Fossils of non-passerines, including ostriches, penguins, and storks, can be described by the Eocene period (50 million years ago).The passerines showed up 36-45 million years ago. Giant birds like New Zealand's Moas, and Africa's Elephant Birds lived until 10,000 years ago.

Recent discoveries of many small feathered theropod dinosaurs in north-east China complicate our understanding of bird evolution. The recently discovered flight-capable Cryptovolans, was a bird with uncinate processes including a keel and ribs. Cryptovolans actually appears more ' bird-like ' than Archaeopteryx, which lacks some of these modern bird characteristics. Because of this, some paleontologists and ornithologists have proposed that dromaeosaurs are basal birds whose larger members are secondarily flightless, i.e. dromaeosaurs have evolved from birds and not the reverse.

Modern birds are categorized as Neornithes, split into the Paleognathae and Neognathae. The Paleognaths include the ratites and the tinamous. The ratites are large flightless birds with ostriches, cassowaries, kiwis and emus included. Many scientists believe that the ratites have lost their ability to fly independently while others claim that the ratites have always been flightless and are more directly related to the dinosaurs than other modern birds. The basal divergence from the remaining Neognathes was that of the Galloanseri, the superorder that comprises the Anseriformes and the Galliforms. The wide variety of present-day forms shows the evolutionary success of birds. For taxonomists they were long common subjects of study. Bird classification is a contentious issue.

Current classifications are based primarily on anatomical and morphological variations in form, plumage and so on. More recently, personality characteristics, compositions, and biological (including DNA) approaches have been used. The Phylogeny and Classification of Birds by Sibley & Ahlquist (1990) is a seminal work on bird classification However, while there is general agreement on the families to which the approximately 9,000 current bird species belong, there is a variety of views on the relationships within and between orders and families.

Entomology, Ornithology & Herpetology: Current Research journal is typically peer-reviewed journals that publish theoretical discussions and articles that critically review published work. It is the evaluation of work by one or more reviewer to assess that article. Peer review is fundamental to integration of new research findings. It allows other researchers to analyse findings and society at large to weigh up research claims and make sure that it fit’s both the journal’s subject-matter focus and its editorial platform.