1. 1.6: Phylogenetic trees and cladograms are graphical representations (models) of evolutionary history that can be tested.
1. Phylogeny

2. Cladograms- Diagrams that group items together based on the number of common characteristics
Determine number of shared characteristics.
Arrange items as a tree showing most commonality possible

3. Clade- an ancestral species and all of its descendents

4. Phylogenetic Tree- cladogram that represents evolutionary relationships.
Use two types of data:
Shared Derived Characters: Physical traits that represent evolutionary history (homologous structures).
DNA/Protein sequence Data: Differences in sequences accumulate as species evolve away from each other.

5. Ex. Vertebrate Phylogeny.

6. Ex. Complete Phylogeny

7. Phylogenetic Tree Construction
Determine similarities among organisms (character table works well).
Arrange organisms in a tree diagram showing simplest possible evolution.
Principle of Maximum parsimony: All else being equal, a trait is assumed to evolve once and be present in all descendants
**strive to make trees as simple as possible

8. SKILL: Create a tree- Selected Vertebrates
Character Table:
Animal
Opposable Thumb
4-chamber heart
Amniotic egg
lungs
Spinal column
Chimpanzee 1
Mouse
Turtle
Frog
Fish
Lamprey

9. Trees are Hypotheses Continual revision:
As more data is gathered, the phylogenetic relationships among organisms are continually revised.
Role of computers:
Computer analysis is needed to determine the similarities in large amounts of DNA/protein sequence information.

10. Lungs
Jaws
Feathers
Notochord
Gizzard
Hair
Lamprey x
Antelope
Bald Eagle
Alligator
Sea Bass

11. Things to Know
The order does not imply any sort of ranking from “primitive” to “advanced”
evolution ≠ progress
The most closely related organisms have the most recent common ancestor
There are many ways to represent a cladogram, and many of these may look different, but will actually be identical.

13. The lines between branches represent time, but they generally aren’t directly related to the length of time Unless there is a labeled axis, do not assume that a longer line represents a longer length of time