1. How the Earth formed About 4.5 billion years ago From a cloud of gas and dust (nebula) that also formed the Sun and other planets and comets and asteroids… “chunks” stuck together, which attracted more chunks, which stuck and attracted more chunks…

2. How the Earth formed Kept getting hit with meteors (bombardment), volcanic eruptions Atmosphere not like today…CO 2, H 2 S First life may have formed 3.8 billion years ago…bacteria.

3. Spontaneous generation Theory stated that nonliving things could turn into living things We don’t believe that anymore Biogenesis: living things can only come from living things. Took some proof…

4. Frencesco Redi 1600’s People believed meat turned into flies Had 2 jars with rotting meat, 1 uncovered and 1 covered with screen Maggots only in the uncovered one Proved only that flies not from rotten meat

5. Frencesco Redi

6. Vital force 1700’s Microscope had been discovered, so the microbes they saw had spontaneously generated due to a “vital force” (life force) in the air. Those microbes grew into bigger forms of life

7. Larazzo Spallanzani 1700’s Believed microbes came from other microbes. 2 flasks, boiled broth, 1 left open and one sealed Open one became contaminated Supposedly the closed one had killed off the “vital force” during heating and seal wouldn’t let back in

8. Larazzo Spallanzani

9. Louis Pasteur Mid 1800’s Swan-necked flasks Boiled broth and left open to air Curve in neck trapped microbes Remained clear for up to a year! If neck broke, contaminated within a day Finally disproved spontaneous generation

10. Louis Pasteur

11. How life formed… The scientific explanation Earth formed about 5 billion years ago from cloud of gas and dust that condensed. Early atmosphere contained ammonia (NH 3 ), hydrogen gas, water vapor and methane (CH 4 ).

12. Oparin and Haldane: Proposed that these simple molecules at high temperatures (e.g. lightning) could form amino acids and proteins Miller and Urey proved it could happen Comets also have traces of amino acids

13. First living things About 3 billion years ago Archaea: simple, one celled, autotrophic (make own food), prokaryotes (no nucleus) Chemosynthesis: use chemicals to make energy Some species still around today, at bottom of ocean by volcano vents. Took CO 2 out of atmosphere and release O 2. Responsible for our atmosphere today

14. Other “advances” Photosynthesis: –First done by cyanobacteria (still alive today…stromatolites) Eukaryotes: –A large cell “swallowed” a small prokaryote –Over time, prokaryote multiplied inside of eukaryote and became mitochondria. –Proof: own DNA, in a ring, multiply on its own

15. Evolution Based on geological evidence, at first Rocks form in layers Older ones at bottom Fossils in rocks similar closer together Farther apart fossils are, more different Late 1700’s/early 1800’s

16. Fossils in rock strata

17. Catastrophism Georges Cuvier Noticed in rock layers that fossils changed as go farther down Notice many sudden changes Said they were due to catastrophes making species extinct

18. Uniformitarianism Charles Lyell Said that the processes going on today, geologically, were going on back then, too So change not by catastrophe, but slowly over long time

19. Jean Baptiste Lamarck Organisms change over time Believed in spontaneous generation, and that simple things could become more complex in their life time Inheritance of acquired characteristics Parents’ traits change and they pass that on to children

20. Jean Baptiste Lamarck

21. Charles Darwin And Alfred Russel Wallace (Darwin published book first) Noticed differences between species as traveled by ship around the world (HMS Beagle) Descent with modification –Traits passed on to children over time

22. Charles Darwin

23. Comparing Lamarck and Darwin

24. 4 Parts of the Theory Overproduction of offspring: nature produces more offspring than can survive. This leads to a Struggle to survive (need food, water, etc.). Within a population there is Genetic variation that makes some creatures better at surviving. These differences are called adaptations. Differential reproduction: Creatures with best adaptations survive to make more like themselves.

25. 4 Parts of the Theory

26. Proof for Evolution So over time, what a species looks like can change Transitional species –Fossils of species in between modern and older set up a series where can see changes

27. Transitional species

28. Proof for Evolution Embryology: –Creatures look very similar when young Homologous structures –Look alike between species (e.g. arm bones) Vesitigial structures –Seem to serve no function, but “left over” from ancestor (e.g appendix, tail bone)

29. Structures Homlogous Analogous

30. Structures Vestigial Humans: –Muscles that move ears –Appendix –Tonsils –Body hair –Tail bone –Wisdom teeth

31. Methods of Evolution Divergent evolution –1 ancestor gives rise to many descendants that are different –If fills up many ecological niches, called adaptive radiation Convergent evolution –Different ancestors’ descendents have similar traits –Called analogous structures (e.g wings)

32. Convergent Evolution

33. Divergent Evolution

35. Adaptive Radiation Evolve to fill many niches, e.g. live in many places or eat many different things

36. Adaptive Radiation