Evolutionary Trees
An evolutionary tree is a branching diagram system that portrays the relationship between different biological organisms. To classify species as related, taxanomists use their physical and or genetic characteristics as clues. If a taxonomist wanted to classify a plant they would take note of its flower and leaf structure, color, root system, embryology, life cycle, behavior, chromosomes, and its biochemistry to determine which other organisms are the most simular. Another term for Evolutionary tree is a phylogenetic tree.
Generalized cladogram
Generalized cladogram

The diagram to the left helps one to understand how the evolutionay tree works. Organism A and B share a common ancester represented by the single asterick. A, B, and C all share a common ancestor represnted by the double asterick, and the same pattern continues down the diagram. The root represents the organism that all of the other organisms have in common making them related. Organism A is also the closest related to organism B according to where it is located.

This video goes through Darwins Evolutionary tree step-by-step from the Earth's earliest cells to today most common species.

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external image phylogenetictreeoflife.jpg


Use the Evolutionary Tree below for question #1.

1. Which species is the most closely related to the Dog?
A) Coyote
B) Golden Jackal
C) Short-eared Dog
D) Gray Wolf

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2. What else is an Evolutionary Tree called?
A) Oak Tree
B) Darwinian Tree
C) Phylogenetic Tree
D) Psychotropic Tree

3. Identify the tecniques that scientists use to classify species as related.

4. Which statement is correct?
A) Archaebacteria evolved from animals, plants, and fungi.
B) Animals, plants, and fungi evolved from protists.
C) Eubacteria and archaebacteria appeared on Earth after protists.
D) Eukaryotes evolved form eubacteria.