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Title: Chapter 14 Diagram Booklet Draw, label, and color:. Fig. 14.2 p. 372 Fig. 14.3 p. 373 Fig. 14.9 p. 379 Fig. 14.11 p. 381 Fig. 14.12 p. 382 Fig. 14.15 p. 385. The Origin of Life. 14.2 Discussion Notes. Origins: The Early Ideas.
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Title: Chapter 14 Diagram BookletDraw, label, and color: • Fig. 14.2 p. 372 • Fig. 14.3 p. 373 • Fig. 14.9 p. 379 • Fig. 14.11 p. 381 • Fig. 14.12 p. 382 • Fig. 14.15 p. 385
The Origin of Life 14.2 Discussion Notes
Origins: The Early Ideas • Spontaneous Generation: the idea that nonliving material can produce life.
Disproving Spontaneous Generation • Francesco Redi: completed an experiment that disproved spontaneous generation in large organisms • Louis Pasteur: completed an experiment that disproved spontaneous generation in microorganisms
Redi’s Experiment • He placed raw meat in jars. • He left some jars uncovered and he covered some jars with cloth. • Flies could not get to the meat in covered jars • Only the jars left uncovered grew maggots • Proving the maggots did not grow from meat.
Redi’s Experiment Maggots No Maggots
Pasteur’s Experiment • Set up an experiment in which air could reach the broth, but not microorganisms • Nothing grew in the broth • He tipped the jar allow microorganisms to enter, and they grew in the broth.
Pasteur’s Experiment Nothing Grew Something Grew
Origins: The Modern Ideas • Biogenesis: the idea that living organisms come only from other living organisms • No one has yet proven scientifically how life on Earth began. • However, there are many theories about the beginning of life.
Simple Organic Molecules • For life to have begun: • Simple organic molecules with carbon must have formed • Molecules organized into complex organic molecules, such as proteins and nucleic acids
Important Scientists • Alexander Oparin: Hypothesized that life began in the oceans • Miller & Urey: tested Oparin’s hypothesis, were able to make simple organic molecules.
Formation of Protocells • Protocell: a large, ordered structure, enclosed by a membrane that carriers out some life functions. • Sidney Fox: completed an experiment in which he made protocells
The first true cells • Anaerobic, heterotrophic prokaryotes: did not use oxygen, did not make food, no membrane bound organelles • Once the food supply was diminished, autotrophs evolved.
Archaebacteria: first autotrophs, live in harsh environments • Photosynthesizing prokaryotes then evolved and supplied the atmosphere with oxygen. • Also lead to the ozone layer being made. • Allowing more complex eukaryotes to evolve
Endosymbiont Theory • Proposed by Lynn Margulis • States that eukaryotic cells evolved from a symbiotic relationship between two prokaryotes
Evidence for Theory • Cyanobacteria resemble chloroplast found in eukaryotic cells • Chloroplast and Mitochondria have their own DNA • Chloroplast and Mitochondria have their own ribosomes