Evolution Notes III • Page Page 1 of 9
Evolution Notes III
Organic Compounds
Three hypotheses
1.____________________________________
2____________________________________
3. ________________________________ — most accepted idea
Earth’s age is estimated to be around ____________ years old. Oldest
sedimentary rocks, ____________ years contain no fossils.
Oldest evidence is molecules of fossil organic material, ____________
Oldest candidate for possible organic microfossils,
3.5 billion
Oldest definitely living ____________ — Bluwago formation, remains
of
____________
algae (prokaryotic cells).
Pre-biotic evolution took approximately ____________ to a billion
years
Earth’s early atmosphere consisted of :
These came from out-gassing from earth’s inside
Note: there was no free ________________ nor _____________.
Remember Ozone is needed to block ______ light from the sun
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Pre-biotic evolution:
Slow evolution of chemical into organic molecules using external energy:
1. _________________
a. _________________
b. ___________________________________________
1. _________________
i. ________________ ________________
ii. ________________ ________________
3. ________________ ________________ (lightning)
Some Experiments:
 In 1953 Stanley Miller mixed the _____________ of primitive earth’s
atmosphere and subjected them to of ________ ________ to simulate
lightning, resulting in the formation of ________ ________.
o Details of the Miller Experiment:
 The apparatus was built from glass tubes and
containers.
 Boiling water, ammonia, methane, and Hydrogen
were passed through an electrical spark.
 A glass trap caught any molecules created by the
reaction.
 (The trap kept the products from being destroyed by
the spark.)
 In a second experiment, hydrogen was bubbled through the molecule
mix and let out of the flask resulting in the formation of ________ _____,
________, _________ and _______________ sugars, urea, and other basic
building blocks of life. The _____common amino acids that were found
in this mixture are the ones most commonly found in living organisms
_____.
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 In lab experiments preformed by Sidney Walter Fox (b. March 24, 1912.
d. Aug. 10, 1998), these amino acids produce thermalproteinoids
under dry and gentle forms of _________, such as those found in
__________________ gradually drying out.
It is felt that proteins were developed before nucleic acids.
 Proteins are attracted to _______ particles.
 The clay particles actually ______the proteins along their surface
and aid in the formation of _______ –molecules.
 These molecules can form into more complex ones.
 There are several different combinations.
 When ________ first appeared it could out compete all other forms
of macro-molecules because it can _____________.
 This had to happen once, because then replication system would
take over and ___________ would occur.
First bacteria cells were strictly _________, living in carbon dioxide and
methane gasses.
_____________first appeared in cyanobacteria (blue-green algae).
This process began the release of _________into the atmosphere and also
allowed for more efficient respiration to occur.
True early forms of bacteria came about around 2.5 million years ago.
First eukarotic cells occurred 1,300,000,000 (1.3x109) years ago. Oldest
multicellular animals are approximately one billion to 7,000,000 years
old.
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Hardy / Weinberg Law of Equilibrium
Determines the expected ________ results from a mathematical equation of
___________(alleles) in a _________ (a group of interbreeding species).
Works only under these conditions:
1. Random and equal ____________
2. Very ____________ population size (infinite number ∞, several 1,000s)
3. No net _________________
4. No ______________(natural or artificial)
5. No ___________ ___________ (in or out of population)
Equation: p2 + 2pq + q2 = 1
Where:
p = frequency of ____________ allele
q = frequency of ____________ allele
It is (p+q)2 factored
Results in:
= p2
= 2pq
= q2
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Class Eye Color:
p2 + 2pq + q2 = 1
?
Brown — pq + p2
?
Blue — q2
?
Total
q2 = #/@
q= square root of q2 = ?
p= 1-(square root of q2) = ?
This results in the percent of BB, Bb, and bb alleles
Usually doesn’t happen in nature, but used because:
1. Nature ________________ these conditions by/because
a. Most mutations _________ each other
b. Probability of _________ (death) having an effect is low
c. Some _________________ have little movement
2. Can use to make ___________________
3. Can alter equation _____________________
4. Use as a tool to measure _____________
Selection:
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It is the differential survival or
individuals of different
of
. Natural selection works
only on ___________traits —
.
Natural Selection:
 Controlled by
numbers of
 Natural selection acts on
The phenotypic trait must be
order for evolution to occur.
 Natural selection acts faster against
than recessive alleles.
, not genotypes.
, however, in
 Evolution does not produce perfectly adapted organisms.
Evolution generally causes the
of existing
structures, not the creation of brand new ones and the results are
often compromises between various needs of the organism.
Three types of selection:
1.
— pushes values toward one extreme
2.
— selection against extremes
(stabilizing)
3.
— two or more favored at same time
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Other types of selection:
1.
the random loss of fixing of genes
because of a small gene pool
2.
the loss of alleles through
immigration or emigration
3. Neutral Alleles
Speciation
Incomplete speciation
1.
— interbreed
2.
— mate less often
How speciation occurs
1.
2.
a.
b.
Classic Examples of speciation:
1.
– geographic
a. Separate
adapt to own area / climate
b. If they can meet and if cannot
c. Must be
then allopatric
a long time — 10,000 to 50,00 years
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Examples:
1. Squirrels of the Grand Canyon were at one time the same species
North Rim
South Rim
Kaibab
Albert’s
Higher elevation
Lower elevation
Eats pine nuts
Eats seeds
Darker fur
Golden yellow fur
White tail
Not white tail
Now they are
species
2. Habitat preference — Apple Maggot Fly originally on Hawthorne
trees
3. Chromosomal Mutation
a. Different ploidy (N)
b. Extremely commonn in plants
c. Instance speciation
i.
reproduction
ii. Females only, no mating, no male needed
iii. Some species of lizards in the Southwest
II
— cline
— character gradient in morphological geographic
variable sup-species — continuing change from one
geographical area to another
Examples:
1. Frogs along the Atlantic Coast
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2. Gulls around Arctic Circle (circumpolary)
III
— environmental disaster
Isolation of small groups of population members and to which genetic
drift occurs
Reasons:
1.
2.
IV
evolution:
This occurs when species evolve into a common
to a common need.
V
form due
evolution.
1. Occurs when species evolve in several directions away from a
2. This happens usually to fill a vacant ecological
Also known as adaptive radiation.
.