1. Evolution

2. Evolution What is evolution?
It is the process of biological change by which descendents come to differ from their ancestors

3. Scientists Scientists who began studying evolution: Linnaeus (1700’s)
Developed classification system of organisms
Proposed that organisms arose from hybridization

4. Scientists Buffon (1700’s) Used evidence of past life
Proposed that species shared ancestors instead of arising separately
Proposed earth was much older than 6000 years

5. Scientists Erasmus Darwin (1731)
Proposed all living things were descended from a common ancestor
Later expanded upon by his grandson

6. Scientists Lamarck (1809) Didn’t believe in extinction
Species evolved instead
Proposed that changes in environment caused behavior to change
Organism passes on these traits to offspring
“Inheritance of acquired characteristics”

7. Charles Darwin
Darwin took a trip to the Galapagos Islands aboard the HMS Beagle
He studied the inhabitants of the island

8. What did Darwin find?

9. Charles Darwin Findings and conclusions: Variation among species
Led him to believe species adapt to their environment
Adaptation- feature allows an organism to better survive in an environment
Leads to change in populations over time

10. Examples of Adaptations

11. horned lizard
pistol shrimp
aye aye
archer fish

12. Charles Darwin Natural Selection
Individuals inherit beneficial adaptations and produce more offspring than others

13. Charles Darwin 4 principles of natural selection: 1. Variation
- Differences among organisms
2. Overproduction
- More offspring increases chance for survival
3. Adaptation
- Certain variations allow to survive better
4. Descent with Modification
- Over time, more individuals in the population will have the beneficial traits

14. Natural Selection Variation Overproduction Descent with Modification
Adaptation

15. Fossil Evidence
No fossil evidence that contradicts evolution has been found
Allows us to see transitions of species over time

16. Anatomical Evidence Homologous structures
Features that are similar in structure, but different in function in different organisms
Supports common descent

17. Anatomical Evidence Analogous structures
Structures that perform similar function

18. Anatomical Evidence Vestigial structures Unused features
Structure had a function in early ancestor
Helps support common ancestry and evolution

19. Molecular Evidence All living things have DNA
Organisms carry pseudogenes
Genes that do not function (vestigial)
Cells have very similar proteins
Marine worms have same proteins in the eye as vertebrates
Comparison of milk protein in whales and hippos:
Hippo
TCC TGGCA GTCCA GTGGT
Humpback Whale
CCC TGGCA GTGCA GTGCT

20. Match the structure Homologous, analogous, or vestigialB A C

21. Population Distributions
Normal Distribution
Frequency of a certain phenotype is near the mean

22. Population Distributions
Directional Selection
Selection favors phenotypes at one extreme
Population shifts toward advantageous trait

23. Population Distribution
Stabilizing Selection
The intermediate is favored and becomes the most common

24. Population Distribution
Disruptive Selection
Both extreme phenotypes are favored

25. Genetic Drift Bottleneck Effect
Occurs after an event greatly reduces the size of a population
Ex. Overhunting of elephant seals

26. Genetic Drift Founder Effect
Occurs after a small # of individuals colonize a new area
Ex. Emerald ash borer

27. Sexual Selection Occurs when certain traits increase mating success
Two types:
Intrasexual
Physical competition among males
Intersexual
Displays among males
Examples:
Intrasexual
Intersexual
Giraffe fight
Bird display

28. Long-tailed Widowbird
Male
Female

29. Evolutionary Classification
Cladogram
Evolutionary tree that proposes how species may be related to each other through common ancestors
Clade
Group of organisms that share certain traits

30. Evolutionary Classification
Cladogram for modes of transportation:
Bicycle
Car
Motorcycle
Airplane
On foot
walking
bicycle
motorcycle
car
airplane
wings
Passengers
enclosed
motor
wheels