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Organization of Life on
earth
Its Origin and Evolution
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Levels of Organization
Biosphere
l
Ecosystems
l
Communities
l
Populations
l
Organisms
l
Organs and Organ Systems
l
Tissues
l
Cells
l
Organelles
l
Molecules
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Levels of Organization
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Biosphere
Everywhere within the Earth’s
atmosphere where life exists.
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Ecosystems
The biotic and abiotic factors within an
environment
Interactions between organisms
Interactions between organisms and the
environment
Cycling of Nutrients
Energy flow
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Community
All living organisms in a particular region
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Population
All individuals of a species in a particular
area
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Organism
A single living thing
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Organs & Organ Systems
Organ
Specialized body parts made of tissues
Tissues work together to perform a specific
function
l
Organ System
Groups of organs that work together to
perform specific functions
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Tissue
A group of similar cells
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Cell
l
Basic unit of:
Life
Structure and function
l
Contains DNA
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Organelle
Structural component of a cell
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Molecule
Chemical structure consisting of atoms
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Diversity of Life
Domain Bacteria
Prokaryotic
l
Domain Archaea
Prokaryotic
Live under extreme conditions
l
Domain Eukarya
Protists (unicellular eukaryotes)
Kingdom Plantae (photosynthetic)
Kingdom Fungi (decomposers)
Kingdom Animalia (ingest others)
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Evolution
On the Origin of Species,
Charles
Darwin
Contemporary species arose from a
succession of ancestors
○
“descent with modification”
Natural Selection
○
Mechanism for descent with modification
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Early Earth & the Origin of
Life
Chemical and physical processes on
early Earth may have produced very
simple cells through a sequence of
stages:
1. Abiotic synthesis of small organic molecules
2. Joining of these small molecules into polymers
3. Packaging of molecules into “protobionts”
4. Origin of self-replicating molecules
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l
Earth formed about 4.6 billion years ago
l
Earth’s early atmosphere contained
water vapor and chemicals released by
volcanic eruptions
l
Experiments simulating an early Earth
atmosphere produced organic
molecules from inorganic precursors,
but such an atmosphere on early Earth
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10/5/09
Water
vapor
C
H
4
N
H
3
H
2
Electrod
e
Conden
ser
Col
d
wat
er
Cooled
water
containing
organic
molecules
Sample for
chemical
analysis
H
2
O
Miller & Urey
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Other Explanations
synthesis near submerged volcanoes
and deep-sea vents
