1. Evolution A. What is Evolution? 1. Several definitions
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a. descent with modification (Darwin)
b. change in gene frequencies within a population
c. All the changes that have transformed life on earth from its earliest beginnings to the immense diversity existing today

2. Evolution History A. Historical Development 1. Jean Baptiste Lamarck
a. French biologist: proposed a theory of evolution in 1801
b. Lamarck’s Theory
i. Organisms strive to improve themselves: “need”
ii. Most used structures develop and less used structures are lost: “use and disuse”
iii. Offspring inherited the acquired characteristics of parents
History

3. Evolution History A. Historical Development 1. Jean Baptiste Lamarck
2. August Weismann
a. Disproved Lamarck ideas by chopping of the tails of mice
b. What?
History

4. Evolution History A. Historical Development 1. Charles Darwin
a. Study theology at Cambridge
b appointed naturalist aboard the ship HMS Beagle
i. mission was to create maps for the British Navy
c. Darwin took surveys and collected samples of plants, animals, rocks, and fossils
History

5. Evolution History A. Historical Development 1. Charles Darwin video1
d. Most famous observations: Galapagos Islands where he spent 2 months
e. Eventually sailed around the world
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History

6. Evolution WHY? History A. Historical Development 1. Charles Darwin
f. Wrote a 200+ page thesis in 1844 outlining his theory but he did not publish
WHY?
g. Alfred Wallace: came to similar conclusions as Darwin in 1858 from observations collected in another area of the world
h. Darwin agreed to a joint presentation with Wallace to the same scientific body.
History

7. Evolution A. 5 ideas of Darwin’s Theory 1. Overpopulation
a. Organisms produce more young than will survive
b. example:
Fly eggs: 250 eggs by one female in one laying
Baby sea turtles
Praying Mantis young from one cocoon

8. Evolution A. 5 ideas of Darwin’s Theory 1. Overpopulation 2. Variation
a. There exists in a population a large amount of variation

9. Evolution A. 5 ideas of Darwin’s Theory 1. Overpopulation 2. Variation
3. Struggle for existence
a. What do organisms struggle for?
i. Lion attack
b. Carrying Capacity: how many individuals can the environment support
i. example: deer in CVNP
4. Survival of the
strongest
fittest
a. Those that survive are the best adapted

10. Evolution A. 5 ideas of Darwin’s Theory 5. Natural Selection
b. Individuals that survive reproduce and pass on favorable traits
c. “Fittest”: those that reproduce most successful
i. Differential reproductive success
5. Natural Selection
a. Environmental pressures select for the best adapted
b. Animated example: DDT and flies

11. Evolution B. People who helped Darwin 1. Thomas Malthus
a. minister, economist
b. Wrote: Essay on Populations
c. Predicted that population would grow faster than food supply
d. Lead to Darwin’s idea of struggle for existence

12. Evolution B. People who helped Darwin 1. Charles Lyell a. geologist
b. Wrote: Principles of Geology
c. Proposed the idea of Uniformitarianism
i. Geological processes are constant through time
ii. Challenged the prevailing thought that the earth was young
iii. Darwin needed large periods of time for natural selection to work
iv. Uniformitarinism provided Darwin the time element needed for his theory

13. Evolution B. People who helped Darwin 1. Charles Lyell/
Uniformitarianism

14. Evolution Natural Selection: How Evolution Works Overpopulation
Genetic Variation
Struggle for Existence
Differential Reproductive Success
Selection occurs based on:
the interaction of the environment and the existing population variations
the more severe the environmental pressure, the more severe the selection process

15. Evolution Natural Selection:
the environment shapes or refines organisms adaptations
Environmental Pressures
resources: food, water, shelter
climate: cold, hot, wet, dry
predation: how does one survive?

16. Evolution Evidences A. Anatomical 1. Fossils
a. Remains or traces left in rock strata (layers) by previous organisms (video: becoming a fossil)
b. Preserved in: rocks, bogs, tar amber, ice
c. Types of preserved samples: imprints, castings, and amber

17. Evolution Evidences A. Anatomical 1. Fossils d. Transitional records
i. Classic example: the horse
e. Famous fossils
archeopteryx;
bird or reptile?

18. Evolution Evidences A. Anatomical 1. Fossils e. Famous fossils
Coelocanth: living fossil