1. Theory of evolution

2. Many ideas were out there to explain how species change over time but the first published was
Charles Darwin in the H.M.S. Beagle traveled the world for 5 years and made observations of living and fossilized plants and animals.
Started to notice relationships among species
Most significant stop- the Galapagos
Found many unique species similar but different then those of the mainland. IDEA
CAN SPECIES CHANGE OVER TIME?

3. Now that an idea was formed DARWIN had to collect evidence
For two decades Darwin worked and experimented and read and borrowed from Thomas Malthus.
Malthus idea was that human population grows faster than food supply
Darwin idea was that individuals struggle to compete in changing environmental conditions. Which individuals survive?

4. Natural selection Mechanism for change in populations.
In Nature organisms produce more offspring than can survive
Due to independent assortment in any population individuals have variations
Individual with useful variations will survive
Over time offspring with certain variations make up most of the population and may look nothing like their ancestors
In Indonesia Alfred Russell Wallace reached a similar conclusion but Darwin was the first to publish.

5. Interpreting evidence after Darwin
Much data has been gathered but as Humans have only been here a short time and what happened before us is subject to interpretation.

6. Evidence for Evolution
Adaptation is variation that aids an organism’s chance of survival in its environment.
Structural adaptations
Mimicry Camouflage
Physiological adaptations
Fossils
Anatomy
Homologous structure Analogous structure
Vestigial structure
Embryology- viruses
Biochemistry- Modern approach

7. Mechanisms of Evolution
What was missing from Darwins theory? Genes
Who evolves Populations or individuals?
Natural selection acts on the range of phenotypes
Evolution occurs as a population genes and their frequencies change over time
Gene pool
How much (percentage) of any specific allele in the gene pool is called Allelic frequency

8. Genetic equilibrium When the frequency of alleles remains
the same over generations
Does it evolve?

9. Changes in genetic equilibrium
Mutation -most lethal but some……. Are useful
Genetic drift- change of allelic frequencies by chance events…
can greatly affect small populations making recessive alleles more common than in the larger population,
Gene Flow- Can be affected by movement into and out of a population
                                                                                                                                                                                                                                            
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10. Three types of natural selection that act on variation
Stabilizing-favors
average individual
in a population

11. Directional selection
Occurs when Natural selection favors on of the extreme variations of the trait

12. Disruptive selection
Individual with either extreme of a trait’s variation are selected for.

13. Physical barriers can prevent interbreeding rendering a new species (speciation) can no longer interbreed
Geographic isolation-
When a physical barrier divides a population
Reproductive isolation
Change in chromosome numbers and speciation
Speciation rates
Gradualism-
slow change over time
Punctuated equilibrium-
rapid change

16. Patterns of evolution
Adaptative radiation

17. Divergent evolution- become more dissimilar over time

18. Convergent evolution Unrelated species occupy similar environments which have similar pressures which make them look similar

19. Review