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Evolutionary History

Evolutionary History

Introduction

People have been naming and sorting things throughout history. Plant taxonomy follows specific rules for the identification and classification of a new species. Classification systems are based on similarities and dbetween species. We now know that these similarities are not simply due to coincidare the result of evolutionary history and sharedcommon ancestors. In this activity, you will havthe opportunity to gain a further understanding ohow all of the plant life around you is related by creating a simple phylogenetic tree.


Before creating a phylogenetic tree of plant specimens you identified, answer these questions from the video on identification and classification and be prepared to share your answers with your classmates:

  • What data have you collected that will help you understand the evolutinary relationships shared by the plants you identified?

 

  • The most closley related plants should have a similar classification. Are two species within the same genus more or less closely related than two species in different genera but in the same family?

 

 

Now you are going to have the opportunity to create an evlotionary tree, showing the relationships between each of your specimens. Follow these steps to create your tree:

1. Organize your specimens by analyzing their relatedness using their taxonomic ranks (see your Plant Classification Table). Note: All of your specimens share the same kingdom (Plantae). As you move to more specific taxonomic ranks, fewer and fewer species willhave the same classification.
Evolutionary History

2. Using a large sheet of paper, start to construct a phylogenetic tree like the ones you see on this sheet. Note: The diagram on the left shows that Specimens A and B are more closely related to one another than they are to Specimen C. This cannot be determined from the diagram on the right.

phylotree1

3. Next, put pictures of specimens you found outside into the diagram. Replace the letters A, B, and C, with pictures (as shown below for letter “A”). Plants in the same genus will be more closely related according to relationship of each specimen.

phylotree2

4. Underneath each picture, include the Family, Genus, and Species name of each specimen.

5. Compare your tree to those of your classmates.

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