CP Biology
2013-2014
Name
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UNIT 3A: Origins of Life
How did Life Begin?
 For thousands of years people believed that living
Where did the first life come from? _there are many
theories but nobody knows for sure
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organisms originated from nonliving matter.
1) Abiogenesis or Spontaneous Generation: the idea
that life can arise from nonliving material.
(Ex: haystacks; flies come from rotting meat;
bacteria arise from broth)
 Francisco Redi in the 1600’s and Louis Pasteur in
1862 conducted experiments which disproved the
theory of spontaneous generation.
2) Biogenesis: the idea of life arising from other living
things.
(Ex. Cats make cats; humans make humans, etc.)
Origins of the Earth
Big Bang Theory (1927): idea which explains what
happened at the very beginning of our universe (~13.7 bya)
– began as an infinitely small, hot dense “speck” that
inflated, expanded and cooled to the size and temperature
of our current universe. Earth formed around 4-5-4.6 bya.
Franceso Redi’s Experiment:_Two jars of meat, one jar
covered in cheese cloth and the other left open to the
air. Maggots formed on the meat in the jar left open
and did not form in the covered jar. This disproved the
theory of spontaneous generation.
Louis Pasteur’s Experiment: He had the goose neck
flask of boiled broth that allowed air to enter but not
living organisms (bacteria). As a result the broth
remained clear without any bacteria appearing.
Compounds in the Primitive Atmosphere
Compound
Elements Present
Molecular
Formula
methane
carbon, hydrogen
CH4
ammonia
nitrogen, hydrogen
NH3
hydrogen
hydrogen
H2
water
hydrogen, oxygen
H2O
carbon dioxide
carbon, oxygen
CO2
Your personal notes, summary of the lesson, and/or questions that you may have:
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Formation of the Oceans
Label the following in the diagram below: He, Ni, Cu, Fe, H2
1) Tremendous amounts of hydrogen and oxygen were
trapped below the crust. These elements combined
to form water vapor, which was released to the
atmosphere
atmosphere.
2) The water vapor condensed in the atmosphere and
NH3
rained down to form vast oceans for 40 million yrs. H2
Sequence of Conditions on Primitive Earth:
He
CH4
CaCO3
crust
core
Cl
Fe Cu
Ni
H2
1) Heavy particles such as iron, copper and nickel were
pulled to the center of the earth.
He
2) Lighter particles such as helium and hydrogen
remained at the surface.
3) Radioactive material and great pressure kept the
center of the earth in a molten state.
4) Over a period of years, the outer surface or crust of What major gas, necessary for life, is missing from the atmosphere
the earth formed over the molten center (4 BYA).
of primitive Earth? _oxygen gas (O2)_______
5) As the outside of the earth cooled, hot gases from the
interior escaped to form the primitive atmosphere.
Look at the pictures of Primitive Earth and Modern
Earth to the right 
What are the similarities between Primitive Earth and
Modern Earth? _Oceans were present along with the_____
__sun; Water vapor is present___________________
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What are the differences between Primitive Earth and
Modern Earth? _the gases in the atmosphere are _
_different (P: H2, CH4, NH3 and M: O2, N2, CO2);
ozone layer on modern earth; life on land; P: volatile
(lots of lightning and UV radiation)
Your personal notes, summary of the lesson, and/or questions that you may have:
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Primitive Earth’s Atmosphere
Two major differences between primitive Earth and
modern earth set the stage for the formation of organic
compounds (hydrocarbons) and, eventually, the origin of
living things.
1) Oxygen (O2) – a highly reactive compound. Will
break bonds that form between simple organic
compounds and destroy them. NOT PRESENT!
2) The atmosphere had abundant energy that could be
used to join atoms that form hydrocarbons.
a) Lacking an ozone (O3) layer, the atmosphere
had abundant UV radiation.
b) Lightning in the atmosphere.
c) Heat from volcanoes above and below ocean level
Theory of Chemical Evolution
In 1924, Alexander Oparin and J.B. Haldane developed
a theory for the origin of organic compounds:
Use your own words to describe the conditions of the
early Earth and the early atmosphere.
(This is #1 from the checklist on the USG of what you
should be able to do by the end of this unit)
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Use the word bank to fill in the blanks below:
precursors, inorganic, spontaneously,
oxygen, primitive Earth
Conditions on primitive Earth gave rise to simple
organic compounds, the precursors to life.
1) CO2, H2 and NH3 are types of __inorganic___
molecules found in the atmosphere on __primitive
Earth__________.
1) Inorganic Matter: like CO2 and NH3, (plus organics
like CH4) in the atmosphere combined using the
energy sources listed above.
2) Scientific evidence indicates that organic molecules
and cells may have formed __spontaneously__ on
ancient Earth.
2)
Simple Organic Molecules: like HCN (hydrogen
cyanide) and formaldehyde formed primitive clumps
of organic matter. – not life (living)…may have
eventually led to life!!!
3) The lack of free atmospheric _oxygen______ and the
abundance of energy on early Earth facilitated the
formation of organic compounds from inorganic
_precursors (to life)_____.
Your personal notes, summary of the lesson, and/or questions that you may have:
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Miller and Urey Support the
Theory of Chemical Evolution
Label Miller and Urey’s apparatus using the word bank
below:
C
Primitive
atmosphere
________
F
lightning
______
 In 1953, Stanley Miller and Harold Urey
developed a model to test the Oparin/Haldane
Hypothesis.
 Gases in the apparatus are CH4, NH3, H2O, & H2 - C
 Sources of energy: electricity (to represent
lightning) - F
_oceans_B
D
Rainfall /
condensation_
_________
 Analysis of substances (organic soup) collected in
the trap: HCN (hydrogen cyanide), lactic acid, acetic
acid, simple amino acids, formaldehyde. - E
 What would happen if you add O2 to the above
mixture?: it would reduce the amount of organic
molecules formed or would not allow them to
form at all (O2 is highly reactive).
E
“organic soup”__
_Heat / i.e. - volcanoes__ A
 Other scientists used UV light in this model and
formed simple organic molecules like HCN which
can be used to form adenine, a nitrogen base.
organic soup, lightning (electricity), oceans,
rainfall, heat source, primitive atmosphere
Your personal notes, summary of the lesson, and/or questions that you may have:
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The Heterotroph Hypothesis
Once simple, organic compounds were formed, polymers of carbohydrates, proteins, lipids and nucleic acids could give
rise to protocells. Protocells: simple precursors to cells then evolved into primitive cells with RNA as the genetic
material.
simple organic compounds  polymers  protocells  primitive cells
Were the first primitive cells autotrophs or heterotrophs?
1) Heterotroph: an organism which requires an
external supply of energy in the form of food as it
cannot make (synthesize) its own.
2) Autotroph: an organism that produces complex
organic compounds from simple inorganic molecules
using energy from light (by photosynthesis) or
inorganic chemical reactions.
Forms of Cellular Respiration
1) Aerobic Respiration: form of cellular respiration
that requires oxygen
Which form of life – autotrophic or heterotrophic – is a
simpler design? Explain.
_synthesis of high-energy organic molecules by
autotrophs requires many enzymes and extra genes.
Heterotrophs are a simpler design than autotrophs;
autotrophs have to make their own food AND break it
down AND require oxygen (which was not present on
primitive Earth.)
Which form of cellular respiration was used by the first
organisms? Why?
_heterotrophs must have been undergoing some type of
anaerobic respiration (fermentation) because O2 gas
2) Anaerobic Respiration: form of cellular respiration
was not present on primitive Earth.
that does not require oxygen
Your personal notes, summary of the lesson, and/or questions that you may have:
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Anaerobic heterotrophs consumed organic matter (organic
“soup”) and underwent anaerobic respiration.~4 BYA
The first autotrophs: 2.5 bya – primitive cyanobacteria –
blue green algae
Photosynthesis provide two important things:
1) a source of food for heterotrophs
AND
2) free oxygen (O2 gas) for the environment and
aerobic respiration
The evolution of O2-producing autotrophs transformed
Earth's atmosphere to one suitable for the evolution of
aerobic metabolism and complex life
Weigh the significance of the evolution of autotrophs in
changing the conditions on early earth.
(This is #7 from the checklist on the USG of what you
should be able to do by the end of this unit)
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The effects of photosynthesis on the development of the
ozone layer:
1) some of the O2 formed by producers is used to form
the ozone layer
O2 + UV light  O3 (ozone)
2) ozone blocks most ultraviolet (UV) radiation from
reaching the Earth
3) One source of energy for formation of organic
compounds is reduced BUT
4) Organisms exposed to the atmosphere are not harmed
by the UV radiation
5) O2 becomes available for aerobic cellular respiration
Your personal notes, summary of the lesson, and/or questions that you may have:
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Evidence About the Past
Based on the following information and the geological
“clock”, label the outside of the clock with the occurrence
of each type of organism listed.
By studying fossil records, we can determine the
occurrence of different types of organisms.
Geological Clock
E
Time from the Present
First Records of:
4.5 BYA
A
origin of the Earth
* ~ 4 BYA
B
prokaryotic heterotrophs
*2.5 – 3 BYA
prokaryotic autotrophs, first
C Evidence of photosynthesis
1.5 BYA
D
unicellular eukaryotes
650 million years ago E
multicellular eukaryotes
400 million years ago F
plants invade the land
300 million years ago G
animals invade the land
200 million years ago H
first mammals
150 million years ago I
first dinosaurs
100 million years ago J
last dinosaurs
*100,000 years ago
K
human development
F
G, H, I, J, K
1
A
4 BYA
B
1 BYA
D
1
2 BYA
C
3 BYA
Your personal notes, summary of the lesson, and/or questions that you may have:
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Phylogenetic Tree
Diversity of Life
3 Domain and Kingdom System of Classification
Eukaryotic
1) Label the kingdoms as eukaryotic or prokaryotic.
2) Label the kingdoms as unicellular, multicellular, or both.
see chart below!
3) Label the kingdoms as heterotrophic, autotrophic, or both.
see chart below!
4) Did the Fungi evolve from Plants? _no_______
5) Are Protists the ancestors of Animals? _yes_______
6) Are Archaebacteria the ancestors of Eubacteria? no___
Prokaryotic
7) Did plants evolve from Protists? _yes______
1ST living organisms
Unicellular, prokaryotic,
heterotrophic, anaerobes
Archaebacteria
Eubacteria
X
X
X
X
Eukaryotic
Prokaryotic
Unicellular
Protista
X
Fungi
X
X
Multicellular
X
Both
Uni&Multi
Plantae
X
X
X
X
Heterotrophic
X
X
Autotrophic
Both
Hetero&Auto
Animalia
X
X
X
X
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