1. Biogenesis and Origin of Life
Chapter 14 -1
Pg and

2. Where did these mice come from?

3. Origin of Life Biogenesis: life comes from other living organisms
Spontaneous generation: early theory that life comes from non-living organisms

4. Evidence Against Spontaneous Generation
Redi’s experiment
Indicated that maggots didn’t come from rotting meat because flies couldn’t land

5. Evidence Against Vital Force
Early Idea
Vital force: Something in the air that gave rise to life
Spallanzani’s experiment: Disproved that organisms came from “vital force” by preventing air contact

6. Evidence Against Vital Force
Pasteur’s experiment: Showed that micro-organisms in the air contaminated the flasks disproving “vital force”

7. First Life Forms/First organic compounds
Spontaneous Origin: the process of life developing from non-living chemical interactions
Ex. “Primordial Soup”

8. Evidence Supporting Spontaneous Origin
Oparin: (1920) Hypothesized that primitive Earth’s atmosphere was
NH3, H2, H2O, and CH4
[No Oxygen]
Miller-Urey: (1953) Produced organic compounds based on the hypothesized composition

9. Primordial Soup: Water
Water has a positive (+) and a negative (-) pole
This makes it polar
Polar substances like water will dissolve other polar substance
Like dissolves like
Pulls apart ionic molecules like NaCl

10. Water bonding
Hydrogen bonds: bonds BETWEEN water molecules (the hydrogen from one water molecule bonds with the oxygen from another water molecule)

11. Molecules to cell-like structures
Non-polar molecules start to group up to avoid water
Leading to cell-like structures beginning to form
Coacervates: Droplets that are made of different macromolecules
Microspheres: small spheres that are made of many protein molecules organized into a membrane
Coacervates can grow, microspheres can bud: show that some aspects of cellular life can arise without direction from genes

12. First Life Forms Role of RNA
Amino acids linked to make a chain that could make shapes like ribozymes (early ribosome) which could replicate itself

13. First Life Forms - The First Cells
Prokaryotes before eukaryotes
3 major trends all interrelated:
Anaerobic  Aerobic
Heterotrophic  Autotrophic
Chemosynthetic  Photosynthetic

14. The First Eukaryotes Endosymbiosis Theory Supporting evidence:
Mitochondria (aerobic prokaryote) and chloroplasts (photosynthetic prokaryote) are thought to be prokaryotic cells that were engulfed by a bigger prokaryote
Created mutually beneficial relationship
Safer environment in exchange for energy source
Supporting evidence:
They have their own DNA
DNA is circular like other prokaryotes
Replicate on their own

15. Sequence of First Cells
Anaerobic
Heterotrophic
Prokaryotes
Chemosynthetic
Prokaryotes
Photosynthetic
Prokaryotes
Endosymbiosis Occurs Here!
Aerobic
Eukaryotes
Photosynthetic
Eukaryotes