Grade+9+1.3+Cladograms

=WEEK FOUR: CLADOGRAMS AND PHYLOGENY=

We could not begin looking at this concept without first viewing this brilliant introduction introduced by David Attenborough, one of the most famous naturalists in the world today.

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So, all life on earth has developed from a single, common ancestor. A cell that existed millions of years ago.

It is this organisation through evolutionary relationships that we will look at next. The process is called Cladistics and the tools used (which are considered tools just like the dichotomous key is seen as a tool) are called cladograms.

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What information can you get from a cladogram?

1. Shared derived characters

2. Probable relationships that exist between members of the group.

3. Probable sequence of origin (evolutionary history) of the group.

You should also be able to tell which members of the cladogram are still living as those who are extinct will not have a lineage line at the same level as all the others. BUT THIS IS NOT CONSIDERED ONE OF THE THREE MAIN PIECES OF INFORMATION.

For help understanding how to interpret a cladogram review the information below:



Please remember that a cladogram can be represented in different ways:

The two diagrams above the same relationships. It should be clear that Groups A and B are more closely related to each other than to Group C. Be sure that you can interpret either form of cladogram.

Try a sample version: [|Cladogram]

As part of your assessments you will need to construct a cladogram. The worksheet, rubric and some extra information are below.

You may find the following diagram helpful for the assignment.