1. theory (casual usage of the word) vs. scientific theory theory- guess scientific theory- an explanation of a natural phenomenon supported by a large body of scientific evidence obtained from various investigations and observations.

2. Germ Theory of Disease- a specific disease is caused by a specific type of microorganism. –The germ theory of disease is considered by many to be one of the most important contributions to science and medicine (if not THE most important) –Before the work of Van Leeuwenhoek, Pasteur, Koch, and others, most doctors believed that diseases were caused by SPONTANEOUS GENERATION- that is, infections arose from nonliving material. –Since it was believed that microorganisms could arise from nonliving substances, scientists and doctors of that time saw no purpose in trying to discover ways to prevent diseases. –In fact, before the germ theory was proposed, doctors would actually perform autopsies on people who died of an infectious disease and then go care for patients WITHOUT WASHING THEIR HANDS IN BETWEEN, not realizing that they were actually transmitting the disease themselves!

3. Atomic Theory- –Even today after hundreds of years of research, no one has yet seen a single atom. –How can we then be certain that atoms exist? –Tested by experimentation- Dalton’s atom Thompson’s atom Rutherford’s atom Bohr’s atom Current electron cloud model.

4. How did life begin? (pgs 8-14) –Spontaneous generation theory- fully formed LIFE could come from NONLIVING matter Recipes for living things- – fish  dried mud –mosquitoes  water –moths  old clothes –flies  meat

5. Francesco Redi- 1668 (pgs. 8-9)

6. Lazzaro Spallanzani 1700’s (pg. 11)

7. Louis Pasteur- 1864 (pgs.12-13) he proved BIOGENESIS- new organisms come from existing organisms

8. Life does not arise from NON-LIVING things. (BIOGENESIS!!) If life comes only from life, then how did life on Earth first begin? (question from page 423 in your bio. book) Life does not come from non-life (chemicals) today but it could have under the conditions of the early earth.

9. Formation of the Earth to multi-cellular life –Big Bang- universe expanding, galaxies are moving apart, like raisins in a loaf of raisin bread! (pg. 423) –Swirling mass of gas and dust –Collapsing in to form the sun (evolution of a star) –Collected as clumps to form the planets-more dense elements to core, less dense to crust, even less dense to form atmosphere – Earth 4.6 billion years old –About 3.8 bya the surface cooled enough for the oceans to form –3.5 bya 1 st fossil evidence of prokaryotic life –1 bya 1 st fossil evidence of eukaryotic life (pg 427 endosymbiotic theory) –Sexual reproduction arises and SPEEDS up the evolutionary process! Leads to much more variation!! (pg. 428) –A few hundred million years after sexual repro. evolved we begin to see the fossil evidence of MULTICELLULAR life forms.

10. galaxies are identified in 2D images (right), then have their distance determined from their spectrum to create a 2 billion light-years deep 3D map (left) where each galaxy is shown as a single point, the color representing the luminosity - this shows only those 66,976 our of 205,443 galaxies in the map that lie near the plane of Earth's equator.

12. First organic molecules-leading to the first life forms –Primordial Soup 1. simple compounds like AMINO ACIDS- can these form from what was believed to be present on the early earth? YES! »Oparin’s Hypothesis- NH 3 ammonia, H 2 hydrogen gas, H 2 O water vapor, and CH 4 methane » other substances-HCN hydrogen cyanide, CO 2 carbon dioxide, CO carbon monoxide, H 2 S hydrogen sulfide »Miller and Urey experiment (pg. 424) formation of amino acids, ATP (an energy molecule) and DNA nucleotides!! 2. Complex compounds formed like PROTEINS (amino acids link together to make proteins) YES! 3. concentration and enclosure- cluster together (pg. 425) YES! 4. clusters grow, reproduce and metabolize CAN’T GET THIS!!