1. E V O L U T I O N

2. Questions to Ponder TRUE/FALSE You can web your hands if you try.
You can acquire traits in your lifetime that will help you survive.
All organisms have the same chance for survival.
All organisms need the same favorable trait.
Evolution of most organisms occurs during their lifetime.

3. THEORIES OF EVOLUTION: LAMARCK VS. DARWIN

4. LAMARCK’S THEORIES: wrong
Acquired trait: a trait NOT determined by genes, it arises during an organisms lifetime as a result of behavior and can be passed onto offspring

5. WRONGLamarck: Acquired Trait
Example: giraffes evolved their long necks by stretching further to get leaves in trees and that this change in body shape was passed on. 

6. CHARLES DARWIN ( )
voyage of the Beagle

8. The study of the Galapagos finches led Darwin to his TWO theories…
Decent With Modification
Natural Selection

9. Darwin’s Theories 1) Descent with Modification
Newer forms appearing in the fossil record are modified descendents of older species
All species had descended from one common ancestor

10. Descent With Modifications - tree of life that links all living things!

11. Modification by Natural Selection
Describes how evolution occurs
organisms in nature produce more than can survive
THEREFORE living things face a constant struggle for existence

12. POPULATIONS HAVE VARIATIONS
2. Variation exists within populations because: - mutation
- Crossing Over/Independent
Assortment (make different gametes)
- Sexual reproduction - Random fusion
of two gametes
Through mutation three variations of neck length exist: Short, Medium and long necks.

13. Let’s review Mutations
Start here A

14. SOME VARIATIONS ARE FAVORABLE
Having a high number of favorable traits gives the organisms an adaptive advantage
3. Non-random Survival and Reproduction
-Individuals with traits best suited to their environment (favorable traits) survive and reproduce in high numbers
The long neck giraffe has the “best advantage” and therefore reproduces more than the others

15. Fitness: organisms ability to survive and pass on its genes
4. These favorable traits have to be heritable (able to be passed down to offspring)
Fitness: organisms ability to survive and pass on its genes
SURVIVORS HAVE FAVORABLE TRAITS TO PASS TO OFFSPRING
Long neck giraffes have baby long neck giraffes

16. POPULATIONS CHANGE OVER TIME
5. Adaption: The number of organisms with favorable traits increases
Populations genetically change to become more suited to the environment
The entire population of giraffes now ALL have long necks
POPULATIONS
CHANGE OVER
TIME

17. Summary:
Natural selection is not an active process: the environment “selects” the traits that are favorable and those that are not
If the environment changes, so must the ...population
**The environment decides which alleles are favored not the individual**

20. Evidence of Evolution 1) Fossil Record

21. Evidence of Evolution Comparative Anatomy
Homologous Structures: same structure but different function

22. Evidence of Evolution Comparative Anatomy
Analogous Structure: Same function but different underlying structures

23. Evidence of Evolution Comparative Anatomy
Vestigial Structure - body part that is evolutionarily reduced or has no use

24. Evidence of Evolution Embryology

25. Evidence of Evolution Molecular Biology