1. EVOLUTIONEVOLUTIONEVOLUTIONEVOLUTION

2. Questions to Ponder TRUE/FALSE 1. You can web your hands if you try. 2. You can acquire traits in your lifetime that will help you survive. 3. All organisms have the same chance for survival. 4. All organisms need the same favorable trait. 5. Evolution of most organisms occurs during their lifetime.

3. THEORIES OF EVOLUTION: LAMARCK VS. DARWIN  Lamarck (1744-1829)  Darwin (1809-1882)

4. LAMARCK’S THEORIES  Jean Baptiste de Lamarck (1744-1829)  Theory: Similar species descend from a common ancestor (evident in fossil record) To Explain how species change he hypothesized:  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. Acquired Trait Example: giraffes evolved their long necks by each generation stretching further to get leaves in trees and that this change in body shape was then inherited. Example: giraffes evolved their long necks by each generation stretching further to get leaves in trees and that this change in body shape was then inherited.

6. CHARLES DARWIN (1809-1882)  Darwin was recommended to be a naturalist on the ship H.M.S. Beagle  Sailed around the World in Beagle for five years-collected specimens and recorded lots of data

7. Voyage of the Beagle

8.  Darwin reasoned that Earth is dynamic, constantly changing –earthquakes, volcanoes, mountain formation-  Changes are a long slow process- organisms must adapt to changes or ?

10. The study of the Galapagos finches led Darwin to his TWO theories!

11. Darwin’s Theories Descent with Modification  Newer forms appearing in the fossil record are modified descendents of older species  All species had descended from one or a few original types of life

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

13. Modification by Natural Selection Describes how evolution occurs! 1. Living things face a constant struggle for existence **organisms in nature produce more than can survive**

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

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

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

17. 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**

18. 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...

19. Outcomes of Natural Selection  Most traits resemble bell curve for phenotypes Natural Selection can alter variation in a population in three ways:

20. Stabilizing Selection  Favors individuals with the average phenotype of the trait (average form have the highest fitness)

21. Directional Selection  Environmental conditions favor individuals of one extreme phenotype

22. Disruptive Selection  Environmental conditions favor individuals of both extremes of the phenotype.  Can lead to creation of a new species

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

26. Evidence of Evolution Comparative Anatomy  Analogous Structure - same function but different structures

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

28. Evidence of Evolution Embryology

29. Evidence of Evolution Fossil Record

30. Evidence of Evolution Molecular Biology

31. Patterns of Evolution Ways species change to adapt to their habitats: o Coevolution o Convergent Evolution o Divergent Evolution

32. Patterns of Evolution Coevolution: Two or more species change together! Examples: 1) Predator/Prey 2) Plant and pollinator

33. Patterns of Evolution Convergent: Two dissimilar species becoming similar Environment selects for similar phenotype (but ancestors were different)

34. Patterns of Evolution Divergent: Two similar species become dissimilar in response to environment