Chapter 14 – where did it all begin? Origin of Life Chapter 14 – where did it all begin?
Disproving Spontaneous Generation Life from nothing Bio/Genesis Life coming from life
Key players Redi Spallanzani Pasteur
Redi’s Experiment Mid-1600’s – People though that flies spontaneously arose from meat Francesco Redi (1668) hypothesized that meat kept away from adult flies would remain free from maggots Experiment gave good evidence for flies coming only from eggs laid from other flies
Spallanzani’s Experiment Lazzaro Spallanzani (1700’s) – designed an experiment to test for microorganisms Hypothesized that microorganisms living in the air and would contaminate the broth in the unsealed flask Opponents claimed that he killed the “vital force” by boiling the broth too long Failed to disprove spontaneous generation
Pasteur’s Experiment Louis Pasteur (mid-1800’s) – Also believed that microorganisms lived in the air Proved, with his year-long experiment, that microorganisms (life) lead to life, not a “vital force” in the air
Needs for life CHON Heat Electricity WATER!!
The First Organic Compounds Miller and Urey (1953) experimentally recreated Earth’s early conditions and found amino acids
Life from Organic Compounds Microspheres Proteins organized as a membrane Coacervates - globs of organic compounds - pre-cursers to first cells
1st Cells Prokaryotes Anaerobic Heterotrophic/Chemosynthetic ozone Autotrophic Aerobic ozone
The First Eukaryotes Endosymbiosis – engulfing simple prokaryotes leads to more complex cells “Specialization” and division of labor