History of Life on EarthJanuary 12, 2009
What is the age of the Earth?a) 4,500 years old
b) 4,500,000 years old
c) 4,500,000,000 years old
d) 4,500,000,000,000 years old
Miller-Urey ExperimentShowed that, under certain
conditions, organic compounds could form from inorganic molecules
The experiment
Life’s Building Blocks
Hydrothermal Vents: energy from the vents could have fueled chemical reactions and the depth of the sea would have offered protection from solar radiation
Space: some meteorites that have hit the Earth’s surface contain amino acids
Really, Mrs. G? Space??
Meteorite Room TourFriday, 8 June 2007
Kris Rhodes excitedly holds Allende, the oldest meteorite known, which
contains the first solids to condense out of the solar nebula over 4.556
Billion years ago! Allende also contains tiny diamonds from super
nova explosions of other solar systems. And last, but not least, it
contains amino acids not of our world.
http://www.nmnh.si.edu/rtp/students/2007/schedule07_mineral_tour_photo_meteorites.html
What process is used to estimate the age of fossil within strata, or layers of the Earth?
a. half-life
b. radioactive decay
c. radiometric dating
d. relative dating
Copralite = Dinosaur dunghttp://i.livescience.com/images/ig25_dinosaur_dung_09.jpg
What has shaped the geologic time scale of the Earth?
a. earthquakes
b. the formation of
the Earth
c. floods
d. mass extinctions
What do some scientists think provided the energy for chemical reactions that produced the first biological molecules?
a. meteors
b. heat from hydrothermal vents
c. ribozymes
d. microspheres
The First Cells Lipids make up cell
membranes Lipids do not mix with water In water, lipids can form tiny
spheres called microspheres. Microspheres may have been
the first step towards cellular organization
Endosymbiosis A mutually beneficial relationship in which one
organism lives within another Larger cells engulfed smaller cells, which then began
to live inside larger cells
Evidence for Endosymbiosis Size and structure: mitochondria are the
same size as most bacteria Genetic material: both chloroplast and
mitochondria contain their own DNA that is different from the DNA of their host cells
Ribosomes: both have ribosomes Reproduction: Like bacteria, chloroplasts
and mitochondria reproduce by simple fission
Which were the first animals to evolve and successfully live on land?a. arthropods
b. reptiles
c. amphibians
d. mycorrhizae
Tapping Timeline
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