Kelly Nienburg - Period 04 - AP Biology

All About Phylogenetic Trees

First… What is a Phylogenetic Tree, exactly?

The word combination Phylogenetic Tree is derived from the word “phylogeny,” which means the evolutionary history of a group or species. The “tree” part is added because the chart somewhat resembles a tree.

A phylogenetic tree, also known as a genetic tree, is a branching diagram showing chronological, evolutionary relationships between organisms and their ancestors. Phylogenetic trees are models of hypotheses of evolutionary history.

https://www.youtube.com/watch?v=fQwI90bkJl4
^Bozeman video on Phylogenetic Trees
Taxonomy, which also helps to organize species into phylogenetic trees, is the organization of organisms into categories. Species are organized by a method called hierarchical classification. The organisms are organized by the words below, with Domain being the broadest category and species the most specific:

“Dreadful King Phillip Came Over From Great Spain” is a good way to remember how to organize these words!

 

How is a phylogenetic tree organized?

It is organized based on some of their physical and genetic traits (DNA). Also, where the organism was discovered. The taxa joined in the tree are said to have descended from a common ancestor. They are put into categories showing their relation to other organisms, either ancestral or descendent.

https://www.youtube.com/watch?v=bILvTe2_FEE

Bozeman video of how organisms are classified and organized^

In a lab we recently did, we had to guess where an unknown fossil went in an example of a phylogenetic tree. We went onto a website and compared its DNA sequences to that of modern day organisms. Through those comparisons and observations, each of us decided where the organism belonged, based on relation to each animal its DNA was compared to.

Citations:

PowerPoint for Phylogenetic Trees

www.dictionary.com

http://www.wiley.com/college/pratt/0471393878/instructor/activities/phylogenetic_trees/index.html
https://bioweb.uwlax.edu/bio203/s2013/phillips_reb2/classification.htm