Cladograms. Phylogenetic Trees, and Dichotomous Keys

Cladograms vs

Phylogenetic Trees

Objective

Interpret cladograms, and phylogenetic trees, and identify organisms by using dichotomous keys.

Cladograms

A branching diagram showing the cladistic relationship between a number of species. -Useful in mapping the evolutionary history of lineages of organism. -It is based on hypothesis. -Branches are equal in length because time is not specific.

Names for Grouping

Paraphyletic: Includes the most recent ancestory but not all the decendants

Polypheletic: unrelated organisms descended from more than one ancestor

Monophyletic: Contains the most recent ancestor and all of its decendants

Reading Cladograms

Vertebrae Cladogram

Things to Notice

-Organisms spaced out evenly-We know order of apperance but not the actual timeline -Cladograms do NOT indicate shared characteristics -A very simple system

Phylogenetic Trees

What is it?

Also demonstrate relationships between species accounting for time and features. -Can also be monophyletic, paraphyletic, polypheletic design

How is this different to a cladogram?

The term cladogram and phylogentetic tree terms are used interchangebly but what do you notice is the biggest difference?