The Evolutionist Theory of the Origin of Life Packet #62 Chapter #26 11/28/2018 4:33 AM

Geologists & The Early Earth Already discussed are macro and micro-evolution, but how do scientists hypothesize the origin of life? Biologists generally agree that life originated from non-living matter. Chemical Evolution The spontaneous production, and accumulation, of small organic molecules from inorganic molecules. 11/28/2018 4:33 AM

Chemical Evolution Is very difficult to test experimentally Four Requirements Little or no free oxygen A source of energy The availability of chemical building blocks Water Minerals Gases present in the atmosphere (All necessary to form organic molecules) Time Necessary for molecules to accumulate and react. 11/28/2018 4:33 AM

Formation of Organic Molecules There are two hypotheses proposed Prebiotic Soup Hypothesis Organic molecules formed near Earth’s surface in a “sea of organic soup” or on rock or clay surfaces. Iron-sulfur World Hypothesis Suggests that organic molecules were produced at hydrothermal vents Cracks in the deep ocean floor 11/28/2018 4:33 AM

RNA World Model FORMATION OF CELL 11/28/2018 4:33 AM

Formation of Cells RNA World Model After small organic molecules were formed, macromolecules were assembled from them. Protobionts were formed from macromolecules Macromolecular assemblages Cells then arose from the macromolecular assemblages The first cell is thought to be a prokaryote bacteriophage Anaerobe 11/28/2018 4:33 AM

RNA—The Organic Molecule RNA, a type of nucleic acid, is a type of organic macromolecule. RNA World Model RNA was the first informational molecule to “evolve” in the progression towards a self-sustaining and self-supporting cell Natural selection at the molecular level resulted in the information sequence DNA-->RNA-->protein 11/28/2018 4:33 AM

Endosymbiont Theory FORMATION OF CELLS 11/28/2018 4:33 AM

Endosymbiont Theory Endosymbiont Theory Eukaryotic cells arose from prokaryotic cells. Certain organelles found within eukaryotic cells evolved from prokaryotic endosymbionts with larger prokaryotic hosts. 11/28/2018 4:33 AM

IMPACT OF CELLS 11/28/2018 4:33 AM

How Prokaryote Hetereotrophs Impacted the Environment Autotrophs, organisms that produce their own food, arose from the prokaryotic hetereotrophs The evolution of photosynthesis changed early life because oxygen was generated Oxygen accumulation in the atmosphere allowed the evolution of aerobes Organisms that use oxygen for a more efficient cellular respiration. 11/28/2018 4:33 AM

The Geologic Record Table 26.1 Page 519 11/28/2018 4:33 AM

Figure 26.20 11/28/2018 4:33 AM