Name:
Location: pretoria, gauteng, South Africa

i completed my Bsc (microbiology physiology) degree in 2005 at University of Limpopo, now im doing my honns in ecological informatics at university of the western cape.

Friday, May 12, 2006

ARE BIRDS LIVING RELATIVES OF DINOSAURS?

In general dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years ago. At the end of the Cretaceous period 65 million years ago, dinosaurs suffered a catastrophic extinction, which ended their dominance on land. Modern birds are considered to be the direct descendants of theropod dinosaurs (3). Birds are bipedal (two feet moving) warm-blooded animals which are characterized by feathers, forelimbs modified as wings and hollow bones (1).

There is evidence that birds evolved from theropod (beast foot) dinosaurs, specifically, members of Maniraptora, a group of theropods which includes dromaeosaurs and oviraptorids, among others (2). Non-avian (dinosaurs) theropods which were closely related to birds were discovered, which shows a clear distinction between non-birds and birds. In northeast China scientists discovered that the small theropod dinosaurs had feathers just like the modern birds (2)

Paleontologists discovered that Cryptovolans are better examples of birds than Archaeopteryx which is from where modern birds evolve. Ornithischian (bird-hipped) dinosaurs share the same hip structure as birds, but paleontologists believe that birds originate from the saurichian (lizard-hipped) dinosaurs. Dinosaurs are descendants of the most recent common ancestors of modern birds and Triceratops (1).

Modern birds are classified as Neornithes, which are split into the Paleognathae and Neognathae. The paleognaths include the tinamous (ancient groups of birds) and the ratites (flightless birds). The ratites are large flightless birds, and include ostriches, cassowaries, kiwis and emus (1).

Paleontologists believe that birds are the descendants of theropod dinosaurs. Descendants of a single common ancestor are related, modern birds are dinosaurs and dinosaurs have, therefore, not become extinct!. Modern birds are classified by most paleontologists as belonging to the subgroup Maniraptora, which are coelurosaurs, which are theropods, which are saurischians, which are dinosaurs. Paleontologists refer to birds as avian dinosaurs and to all other dinosaurs as non-avian dinosaurs. Dinosaurs are referred to as a synonym for non-avian dinosaur, and bird as a synonym for avian dinosaur (meaning any animal that evolved from the common ancestor of Archaeopteryx and modern birds) (3).

Birds are living dinosaurs because birds evolved from theropod dinosaurs which means when the dinosaurs died out birds continued with the legacy. Some of birds resemble dinosaurs like the ostrich; they have feathers but cannot fly the same as some dinosaurs. They are both warm blooded animals and they take care of their offsprings. Some paleontologists believe that birds are dinosaurs so dinosaurs did not die out because birds are carrying the dinosaurs legacy.

Reference:

1. Wikipedia contributors. Council of Science Editors [Internet]. Wikipedia, The Free Encyclopaedia; 2006 May 8, 20:26 PTA [cited 2006 May 10]. Available from: http://en.wikipedia.org/wiki/Birds
2. Wikipedia contributors. Theropoda [Internet]. Wikipedia, The Free Encyclopaedia; 2006 Apr 2, 04:52 PTA [cited 2006 May 10]. Available from: http://en.wikipedia.org/wiki/Theropoda
3. Wikipedia contributors. Council of Science Editors [Internet]. Wikipedia, The Free Encyclopaedia; 2006 May 9, 17:38 PTA [cited 2006 May 10]. Available from: http://en.wikipedia.org/wiki/Dinosaurs#Evolution_of_dinosaurs

Lethabo Mosomane
CSIR
Pretoria
0001
Tel: 27 12 841 2133
Fax: 27 12 842 3676
mail: lmosomane@csir.co.za
http://lmosomane.blogspot.com

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