Biodiversity

Wednesday, May 10, 2006

DISCUSSION OF BIRDS AS THE LIVING RELATIVES OF THE DINOSAURS

The idea that birds have the close relationship with the dinosaurs remains a controversial issue among the paleoanthropologists. This is because scientists also remain divided among themselves about the issue surrounding the relationship between the two species, the ''birds and the dinosaurs'' (Willis, 1997). Some of the scientists believe that birds have descended from the dinosaurs. In other words dinosaurs are thought to be the ancestors of the birds. Scientists made their assumptions based upon the relationship between the birds and the dinosaurs by studying the fossil remains.

Some scientists based their argument in the fact that the resemblance which exists between the ''fossils of the birds and the dinosaurs suggest the closely relationship'' (Wikipedia contributors, 2006). They were arguing on the basis of the similarities without considering the dissimilarities between the fossils of the two species. For example, birds do not have the same number of the toes, some have three while others have five and more, depending on the continent in which the species are found. In the other cases, some of the bones found in the toes of the birds resemble that of the reptile. Therefore, the question remains, can we say that reptiles are the ancestors of birds?

Scientists further argue that there is no relationship between the birds and the dinosaurs. This time they based their argument in the fact that the ribcage in the fossils of the dinosaurs are compressed from side to side, where on the other side the ribcage in the fossils of the birds are compressed more from back to their belly. By citing the above mentioned differences in ribcage, some scientists believe that the differences between species do not matter most, what matter most is their similarities. The bones in the wing of the bird has been also compared with the bones of the front feet of the dinosaur and the results which have been found indicated that the bones in the wing of the bird and the bones in the front feet of the dinosaur are similar to the bones of any species.

The ''fossils of the birds were also compared with the fossils of the reptiles than that of the dinosaurs'' (Willis, 1997). This is because it has been found that birds and reptiles have many features that they share which are also common in both the species. Characteristics such as long bones; wingless or wings with four functional fingers; long, slender, vertebrated tail; slender, recurved teeth, set in socket and vertebrae biconcave are also found in both the birds and the reptiles. The above mentioned characteristics are different from those which are found in the dinosaurs, such as very hollow bones, fore legs very short, feeble and not used in locomotion.

In conclusion one can also say that the relationship which is thought to have being existed between the birds and the dinosaurs is still unknown. In other words the missing link which is the information confirming the relationship between the birds and dinosaurs is still not known. This is because scientists believe in the process of evolution in order to find the link which can show us that dinosaurs are the ancestors of the birds. The process of evolution is still on, which means that new evidence may be found which will add to the evidence which is already available.

References:

Wikipedia contributors. Dinosaurs [Internet]. Wikipedia, The Free Encyclopaedia; 2006 May 09, 18: 48 UTC [cited 2006 May 10, 15: 12]. Available from: http://en.wikipedia.org/wiki/Dinosaurs

Wikipedia contributors. Birds [Internet]. Wikipedia, The Free Encyclopaedia; 2006 May 08, 22: 58 UTC [cited 2006 May 10, 15: 28]. Available from: http://en.wikipedia.org/wiki/Birds

Willis, P. 1997. Working out relationships. [Online]. Available from: http://www.txtwriter.com/onscience/Articles/dinoblood.html


Peter Muvhali
CSIR PTA
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URL: http://blogsoccer-peter.blogspot.com/

1 Comments:

  • Me again...

    Again, the whole grammar thing...Your opening sentence is especially confusing. The way you examine the debate around the dinosaur-bird relationship is interesting, if a bit confusing (what do you mean when you say "the missing link is still not known"?). I'm glad to see you using non-Wiki references, though.

    Nick

    By Blogger NcK, at May 17, 2006 9:23 AM  

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