April 28, 2011

5.3 [ Homologous structures, Embryology, Vestigial Features, Biochemistry ]

     Features with similar structures but different functions are called homologous features. A bat’s wing and a whale’s flipper are homologous features because they have similar bone structures. But one is mainly for flying through the air while the other is to swim through water. Structures which are similar in appearance and function, although have different evolutionary attributes are named analogous features.  The wings of a fly, a moth or a seagull are analogous because they have all developed the same function and slight appearance but developed differently depending on the animal’s surroundings,  they all have one common function which is flight. With the power of technology moving at a ever consistent rate, scientists can pick traits they want. This is called artificial selection,a desired trait such as two dogs that are tall- are bred together and the next generation of dogs will be even bigger and taller. If artificial selection is continued, the population will be taller.
 



     Vestigial features are basically the useless structure that serves no function. Although at one point it may have served a purpose. Like in the wings of ostriches,emus and other flightless birds.They are remnants of their flying ancestors' wings, useless in there current state they have not been eliminated because nature works very slowly. Although they do nothing and serve no purpose they still are there. In embryonic development  evolutionary similarity  among species if evident. Similar features in development appear, human embryos posses a tail like feature similar to those of chickens or fish. The tail serves no function but later forms the first stages of the tailbone. Another way to determine if two species are related is to look at ammino acids. Amino acids are a chemicals that contains nitrogen which can form proteins. For example a ostrich will have different ammino acids from a red panda. 



      Another adorable animal that has vestigial features is the kiwi... bird. Its a bird with feet and a long beak. Its vestigial features are its former wings, it no longer has arms. Although it still has the bones that its ancestors had which means at one point in its evolution it had wings.


Ritter, B., Burley, K., & Fraser, D. (2007). Chapter 5 Evolution: Evidence of Evolution from Biology, Biology (p. 144-149). Nelson. (Original work published 2007)

http://www.photochart.com/photo_2457_Bad%20Hair%20Day.html N.p., n.d. Web. 28 Apr.2011

http://fc06.deviantart.net/fs39/i/2010/119/2/4/Kiwi_by_Alejandra_perez.jpg

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