1. What is biological Evolution?
Genetic change over time
AKA
Descent with modification (pg 297)

2. Each generation is a little different from the previous, and the original
The differences between individuals in a population is called variation
What are some variations between the people at school?

3. Biological Evolution
Is based on common descent which means different species descend from a common ancestor
***Think of a common ancestor you share with your sibling.
*** Think of a common ancestor to you and your cousins.

4. Species
A group of similar organisms with the ability to breed and produce fertile offspring (pg 324)

5. Species?
Species: Equus asinus x Equus caballus

6. Pg 343
Phylo-genetic Tree
Chart
Diagram
Genes
Inheritance
DNA
Tribe
Race
Kind
Type
A phylogenetic tree is a branching diagram that classifies species into groups based on evolutionary relationships

7. Like a time line, from bottom to top.
How do they work?
Like a time line, from bottom to top.
A, B, C and D are all modern species… and anywhere on the lines are species that once existed.
Present
Past
A B C D
Common ancestor to C and D
Speciation (new species arises)***
Common ancestor to all, A, B, C and D

8. Stop and think about it!
A B C D
But now think – different species, not different people

9. When new species arise due to
Speciation
When new species arise due to
Behavioral Isolation (326)
Reproductive Isolation (326)
Geographical Isolation (327)
Different courtship behaviors prevent them from reproducing
Different timing of reproduction prevent them from reproducing
Different locations prevent them from reproducing

10. Look at the figure on pg 325 Read the caption for figure 15-3
How are the skunks isolated?
Behaviorally?
Geographically?
Reproductively?

11. The more characteristics organisms have in common, the more closely related they are, and the closer together they are on a phylogenetic tree.

12. Important things to know:
Each branch shows a different characteristic (ex – hair, four limbs), and everything after that branch has that characteristic

13. Important things to know:
The length and number of branches in between indicate how closely related organisms are to each other
For example: Rabbits and Primates are more closely related than Rabbits and Amphibians.
Short branches, close together = closely related

14. Important things to know:
Right to left doesn’t matter. The organization of branches is what matters
Both show human and mouse are closest relatives, human and fish are the most distant relatives

15. Important things to know:
Length of line matters!!!
REMEMBER it is like a timeline too!
Present ≠
Past

16. Trees – not ladders

17. Scientists agree humans did not evolve from a chimpanzee or gorilla
Humans and chimps are evolutionary cousins, and came from a common ancestor that was neither a human or a chimpanzee
Humans are not “higher” or “more evolved” than other organisms. Since our lineages split, each species has evolved unique traits specific to our own species

18. HOMEWORK
Phylogentic Tree Practice!