Transcript The Origins Of Life

By
Aaron Hebson
Can Feng
Nya Smith
Formation of Earth and the Moon
 Giant Impact Hypothesis:
 4.56 billion years ago a Mars sized planet named Theia collided
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with young earth
Disintegrated mantles of both planets, and the debris formed
into Earth’s moon
Evidence: Lunar rocks rich in sodium, potassium, zinc, and lead
which is a result of the vaporization
If vaporization did not occur, lunar rocks would be composed of
heavy isotopes
HOW THE MOON FORMED!!
http://dsc.discovery.com/tv-shows/other-shows/videos/othershows-how-the-universe-works-videos.htm
Heavy Bombardment
 Started around 4.1 billion years ago and ending around 3.9
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billion years ago
A hypothesis that states a influx of planetary
bombardment of comets and asteroids
It was an essential for developing large plants, and were
expected to give the plants in our solar systems most of
there mass
A hypothesis predicts that the cause of this bombardment
was due to the planetary migration of the large gas planets
This caused the asteroid and comets the orbited around
them to continuously collide with terrestrial planets
Earth’s Cooling
 Occurred in the Hadeon eon,
around 4 billion years ago
 Water vapor was formed by
collision of large terrestrial
bodies
 Comets and asteroids that
collided with earth contained
large amounts of ice
 Condensation of this water
vapor formed the oceans we
know today
Stromatolites
 Time period: 3.5-2.5 billion
years ago
 Sheets of microbial collect
sedimentary particles and
undergo photosynthesis
 Pillow-like rock formation
formed as a byproduct
 Proliferation of
cyanobacteria soon
followed allowing for excess
oxygen in atmosphere
Primordial Soup
 The organic soup model
hypothesizes by Miller/Urey
suggested that life began from
a combination of chemicals
resulting in monomers
 These monomers were created
through some energy source,
such as lightning
 This organic soup of
monomers can then be used to
make more complex molecules
Hydrothermal Vents
 The Deep Vent Model suggests that
life formed in hydrothermal vents
 These vents are formed when two
geographical plates move apart,
releasing lava into the ocean
 This lava heats the ocean providing
safe havens for life to form
 Monomers could be present in these
vents to sustain life
Meteorites
 The Solid Reactive
Surface Models suggests
that organic materials
used to create life came
from meteorites and
comets
 These organic materials
would be deposited onto
the earth’s surface, and
later used to create
complex beings
Monomers- Nucleotides
 Nucleotides are simple organic
molecules
 Composed of one phosphate, a
pentose sugar, and a nitrogenous
base
 These monomers are used to build
nucleic acids
 The acids can be used for various
functions in life such as storage,
transfer of vital information, and
even enzymes
Monomers- Fatty Acids
 Monomers used to construct
fat through the combination
of the fatty acid and glycerol
 A long carbon skeleton
ending with carboxyl groups
 The carboxyl group may differ
from each other in their
functional group, designating
the name of the acid
 Extremely hydrophobic
Monomers- Phospholipids
 Similar to fats except only two
fatty acids are attached to the
glycerol
 Phosphate and Choline groups
are attached to glycerol to form
hydrophilic head
 Fatty acids are remain
hydrophobic
 Phospholipid bilayer is formed
in aqueous solutions, resulting
in a membrane
Monomers- Micelle
 A structural form of phospholipid bilayer in an
aqueous solution
 Hydrophilic heads form around the fatty acid chains
forming a small sphere
Monomers- Vesicle
 A small bubble that
forms inside a cell
 Enclosed by a
phospholipid bilayer
 Can form naturally such
as endocytosis or
exocytosis
 Used to organize cellular
function, transport,
metabolism, etc.
Protocells
 Aggregates of abiotically
produced molecules
surrounded by a
membrane or membranelike structure
 Exhibit certain properties
of life such as a simple
reproduction and
metabolism
Formation of Nucleotides
 Abiotically with the
help of clay
 Miller/Urey’s
experiment also
showed that an influx
of energy could cause
the creation of
nucleotides
RNA Hypothesis
 RNA First Hypothesis states that RNA played a
significant role in protein synthesis and catalytic
functions
 Most likely formed due to it’s diverse descendants,
mutations, and reduced uniformed structure
Ribozymes
 RNA functioning as
catalysts
 Make
complementary
copies of RNA
 Remove segments
from themselves
 Excising other
molecules
DNA in Cells
 DNA formation: one theory suggests that RNA organisms
made DNAs.
Evolution of Cells- Endosymbiosis
 Primitive prokaryotes engulfing: aerobic prokaryote
(mitochondrion)
photosynthetic prokaryote (chloroplast)
Multi-cellular Organisms
First
multicellular
organism: 1.2 bya,
small algae.
Cambrian Explosion
 Around 500 MYA
 Sudden Appearance of
phyla animals during
the first 20 million years
of Cambrian period
K-T Event
 Around 230-65
MYA
 CretaceousTertiary Extinction
Event occurred
 Thought to of
occurred by a large
asteroid or
increased volcanic
activity
Homo erectus
 Homo sapiens evolved from Homo erectus about 200
TYA
 Mass Inhabitation (We’re awesome)