1. Abiogenesis The spontaneous generation of life from non-living matter.
It was widely held that maggots arose spontaneously in rotting meat or broth.

2. Francesco Redi (Italian 1668)
One of the first to disprove spontaneous generation. An Italian doctor who proved maggots came from flies.

3. Lazzaro Spallanzani
Some scientists believed that there was a life force in the air
He tried to disprove the life force theory
He was unsuccessful
There are microorganism in the air

4. Louis Pasteur Successful in proving there was no life force
The curved neck allowed air to pass but trapped microorganisms

5. But how did life first form?
Biogenesis
All living things arise from other living things
But how did life first form?

6. RNA Theory The first molecules of life were RNA RNA
Carried genetic information
Can be replicated
Can make proteins
Is a catalyst
Similar in form to ATP
RNA evolved into DNA

7. Oparin (1930)
Spontaneous generation did occur once at the beginning of life
Believed that at high temperatures and with electrical charge the early gases could combine to form simple organic compounds
As the Earth cooled the organic compounds collected in the oceans = Primordial soup

8. Miller & Urey (1953)
Tested Oparin’s Hypothesis under laboratory conditions and produced some amino acids and sugars

10. Alternative Theory
Metorites may have brought organic compounds (amino acids) to Earth

11. First Cells
They were:
Prokaryotic
Anaerobic
Herterotrophic

12. Endosymbiotic Theory Lynn Margulis
Evolution of eukaryotic cells
Eukaryotic cells evolved from large prokaryotic cells that were invaded by small aerobic and small photosynthetic prokaryotes

13. LaMarck
Lamark said organisms acquired traits by using their bodies in new ways
These new characteristics were passed to offspring
Lamark was totally wrong!

14. Decent with Modification (Change in Species Over Time)
Evolution
Decent with Modification
(Change in Species Over Time)

15. Mechanisms for Evolution
Natural Selection
Environmental Pressures
Variation
Competition
Isolation
Sexual Selection

16. Sexual Selection Sexual Selection Variation Competition for mates
Choice

17. Charles Darwin
As a result of his travels to the Galapagos islands and extensive studies of various organisms
He developed 2 major theories
Decent with modification
Modification by natural selection

18. Rules for Natural Selection
1. Organisms differ; variation is inherited
2. Organisms produce more offspring than survive
3. Organisms compete for resources
4. Organisms with advantages survive to pass those advantages to their children
5. Species alive today are descended with modifications from common ancestors

19. Natural Selection

22. Methods of Natural Selection
Stabilizing – Favors the average form of a trait
Directional – Favors the extreme form of a trait
Disruptive – Favors both extremes

23. Antibiotic Resistance

25. Speciation Geographic isolation Reproductive isolation
Geographic barrier between populations
Reproductive isolation
Pre-zygote – No breeding
Different mating seasons
Not recognizing an organism as a potential mate
Post-zygote – Fertilization
Offspring are sterile or no zygote is formed

26. Evidence for Evolution
Fossil record
Homologous body structures
Embryology
Geographic distribution
Biochemical evidence (Genetic)

27. Fossil Record The fossil record infers the history of the Earth
Shows new life forms have arisen during the Earth’s history
Shows diversity in the life forms

28. Relative Dating Vs. Radioactivity
Where fossils are located in the strata
Not as accurate
Uses the degradation of radioactive elements
Example: Carbon Dating
More accurate

29. Homologous Body Structures
Structures look similar but function differently

30. Vestigial Organs Organ that serves no useful function
e.g. Appendix, tailbone, Wisdom teeth

31. Embryology Similarities in Embryology
In their early stages of development, chickens, turtles and rats look similar, providing evidence that they shared a common ancestry.

32. Geographic Distribution

34. Biochemical Evidence Genetic material in all organisms is similar
Shows a common ancestor for all living things
DNA

35. Pace of Evolution Gradualism – Slow and steady change over time
Punctuated Equilibrium – abrupt change followed by little or no change