Transcript Power Point 1 - G. Holmes Braddock

SC.912.L.15.8
Conditions on early Earth
• The gases thought to be on early earth were
ammonia, methane, carbon dioxide, and NO
oxygen.
• The Miller-Urey experiment demonstrated
that organic compounds could be made by
passing a electric current (simulating
lightning) through a closed system that held a
mixture of gasses and water.
Theory of Endosymbiosis
• Explains the origin of chloroplasts and
mitochondria and their double membranes.
• That chloroplasts and mitochondria are the
result of years of evolution initiated by the
endocytosis of bacteria and blue-green algae.
Eukaryotic Cells
• A cell with a nucleus
• Present in all Eukaryotes (organisms whose
cells contain complex structures enclosed
within membranes).
Chemical Evolution
• The formation of complex organic molecules
from simpler inorganic molecules through
chemical reactions in the oceans during the
early history of the Earth
• The period of chemical evolution lasted less
than a billion years.
Organic Molecules
• Organic molecules are molecules that are
normally found in or produced by living
systems.
• The are essential for life on Earth.
Louis Pasteur contributions
• Pasteur discovered the role of bacteria in
fermentation.
• His experiments with bacteria conclusively
disproved the theory of spontaneous
generation and led to the theory that infection
is caused by germs.
Contributions of Oparin
• In 1924 he put forward a theory of life on
Earth developing through gradual chemical
evolution of carbon-based molecules in
primordial soup.
Contributions of Margulis
• Her most important work was the
development of the serial endosymbiotic
theory (SET) of the origin of cells, which posits
that eukaryotic cells (cells with nuclei) evolved
from the symbiotic merger of nonnucleated
bacteria that had previously existed
independently. In this theory, mitochondria
and chloroplasts, two major organelles of
eukaryotic cells, are descendants of once freeliving bacterial species.
Miller and Urey
• The Miller-Urey experiment demonstrated
that organic compounds could be made by
passing a electric current (simulating
lightning) through a closed system that held a
mixture of gasses and water.