1. Do Now: 5/17
Objectives:
Define homology and distinguish homologous structures from analogous ones.
Use homology to make a cladogram of vertebrate animals.
Task:
Any two species or organisms on Earth share a common ancestor in evolutionary history. The more related they are, the more recently the common ancestor lived. Arrange the organisms below from those that share the most recent common ancestor with humans to the most distant:
Snake, tree, chimpanzee, mouse, E. coli bacteria

2. Schedule Reminder Today: Homology (activity due tomorrow)
Tomorrow: Review
Thursday & Friday: Unit Test
Next week: HSA Review

3. Common Ancestry Explained:
1. Who are the most recent common ancestors (MRCA) of Individuals III-1 and III-2?
2. Who are the MRCA of individuals III-1 and III-6?
3. Which pair share a more recent common ancestor?
4. Which pair have the most genetic similarities?
With relatives and with other species, the more recently you share a common ancestor, the more genetics you have in common.
So: Humans didn’t “come from” monkeys or apes… but monkeys, apes, and humans share some ancient common ancestors.

4. Homology = Similarity
Homologous structures are alike in basic structure and ancestry (like flippers and wings)
Molecular homology (DNA or Protein) works the same way

6. Homology Matrices
Amino acid sequence differences in a homologous protein
Lemur
Gorilla 10
Chimpan-zee 14 3
Human 15 2 1
Bonobo 7 4
Orangutan 9
Macaque 8 6
Based on the data above,
Which two species are the most closely related?
Which are the most distantly related?
Which pair shared a common ancestor more recently, bonobos and humans or bonobos and chimps?

7. Organisms are Classified by their Similarities and Differences
Phylogeny is how groups of organisms are related to each other
A cladogram or phylogenetic tree is a diagram that shows these relationships

8. Cladogram

10. Making a Cladogram
We will be making a cladogram that shows how 7 different organisms are related to one another based on their characteristics

11. The animals

12. The Characteristics
Paired Appendages
Canine Teeth
Mammary Glands

13. Amnion
Paired Legs
Vertebral
Column

14. Foramen Magnum