Phylogenetic Trees

   

Figure 1 - Tree of life

     Its time, to speak on the unspeakable, the truth about phylogenetic trees. You may have been told things which are totally false of phylogenetic trees and unlike christmas trees, this is the tree of life. Phylogenetic trees represent traits that are either derived or lost due to evolution. For a better understanding, think of the absence of legs in some sea mammals.  Originally whales were four footed land animals but due to evolutionary changes these legs began to disappear and become a vestigial structure. The Phylogenetic tree can explain this process by illustrating the speciation that has occurred, in that relatedness of any two populations on the tree is illustrated by how recently two groups came from a common descendant.

     

 Figure 2 - Cladogram.

     Cladograms also play a major part when dealing with phylogenetic trees. A cladogram is a diagram used in cladistics which also shows relations among organisms. Basically these two diagrams are identical when explaining how organisms lost or gained certain traits. Click the link to have a more broad understanding of cladogram.  Video on Cladograms 

    Now that I have explained the significance and the use of Phylogenetic trees and cladograms. Stay tuned so I can explain how phylogenetic trees and cladograms can be constructed from morphological similarities of living fossil species, and from DNA and protein sequence similarities. Usually phylogenetic trees are constructed from morphological similarities. Such as if you begin to look at the vertebrae of one animal this can lead to the conclusion of how other animals may have, "so to speak", came from this this organism. If you take a glance at the image in figure 2  you can see that sharks were the first ones to have a vertebrae and from this came the Ray-finned fish and so on. Now when looking at DNA sequences you get the exact similarities in an organisms so this will be much easier to place organism along a phylogenetic tree or cladogram.

Newly founded skull.

     It is also important to remember that phylogenetic trees and cladograms are dynamic, meaning that they are constantly being revised. These changes happen because of the progression of technology and are based on the biological date used, new mathematical and computational ideas, and current and emerging knowledge. For example theres been a new skull that has been found recently and reports are saying that is will spark evolution controversy. If this skull is accepted by scientist it will have the possibility to change the current phylogenetic tree. 


Sources

"Reading Trees: A Quick Review." Reading Trees: A Quick Review. N.p., n.d. Web. 05 Oct. 2014.

"How to Read a Phylogenetic Tree." Emergence, Evolution and Epidemiology. N.p., n.d. Web. 06 Oct. 2014.

"UNM Biology Undergraduate Labs." Untitled 1. N.p., n.d. Web. 06 Oct. 2014.