1. Evolution

2. History of the theory
Jean-Baptiste Lamarck  one of the first to recognize organisms have changed
Published ideas in 1809
Proposed that through selective use or disuse of organs, organisms could acquire or lose certain traits during their lifetime
He did not understand how traits were inherited, but he realized that organisms adapt

3. Thomas Malthus  1798 published a book that said the human population was growing faster that the earth could supply
He was afraid that the growing population would result in not enough living space or resources

4. Darwin's observations
Darwin sailed around the world on the H.M.S. Beagle in 1831 took 5 years
He noticed that the same type of animals had noticeable differences
On each island, he would see different traits unique to that particular island
Published observations in On the Origin of Species

5. Natural Selection Darwin’s evolution explanation
Struggle for existence – all organisms compete for resources
Survival of the fittest – each organism has an environmental fitness
This fitness is the result of adaptations
Whoever is the most fit for the environment will survive

6. Certain traits are beneficial and enable the organism to survive
These will be passed on to future offspring's
He also proposed that “bad” traits will not be passed on

7. Evidence for evolution
Structural Adaptations
Mimicry
camouflage
Physiological adaptations
Changes in metabolic activities
Fossils
Biochemistry
Nearly all organisms share DNA, ATP, and enzymes
Embryology
At one point, all embryos look similar

8. Mimicry

9. Camouflage

10. Bacterial Adaptations

11. Anatomy Homologous structures Analogous structures
Similar in arrangement and function
Forelimbs in crocodiles, whales, birds
Analogous structures
Similar function, different structure
wings
Vestigial structures
No modern-day purpose
Ostrich wings, pelvic bones in whales

12. Vestigial Structures

13. Homologous structures

14. Mechanisms of Evolution
Populations, not individuals, evolve
Gene pool – all of the population’s genes put together into 1 pool
Allelic frequency - percentage of a specific allele within the population
If alleles stay the same  genetic equilibrium
Anything that changes the alleles results in evolution

15. Natural selection and variation
Some variations may increase or decrease chances of survival
Stabilizing – favors the average individuals
Directional – favors one of the extreme variations of a trait
Disruptive – both extremes are favored

17. Evolution of Species
Speciation  process that produces two species from one
Reasons:
Geographical isolation
Reproductive isolation
Changes in the gene pool
Ecological competition
Continued evolution

19. Patterns of Evolution
Adaptive radiation  species evolve to fit habitats
Divergent radiation  members of a species become less alike (adapt to environment)
Convergent evolution  unrelated species become more alike