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Evolution Noteguide
I.
History of Life
A. Early History of Earth
i. Early earth was inhospitable
1. hot, with many ___________
2. little free ________ and lots of ______________
3. other gases present: nitrogen, methane, ammonia, hydrogen and water vapor
B. History in Rocks
i. Fossils are ____________________
1. any trace of a _______________________________
2. can infer the structure of the organisms, what they ate, what ate them, and the
environment that they lived in
ii. __________________- detectives to the past
1. scientists who collect, study and classify fossils
iii. Fossils occur in _________________________
1. sedimentary rock is formed when exposure to rain, heat, wind and cold breaks
down existing rock into small particles of sand, silt and clay.
2. The particles are carried by streams and rivers into lakes or seas where they
eventually settle to the bottom.
3. As layers of sediment build up over time, dead organism may also sink to the
bottom and become buried.
4. The weight of layers of sediment gradually compresses the lower layers and
along with chemical activity, turns into rock
iv. Non-rock fossils
1. fossils can be found in __________
ex. woolly mammoth
2. fossils can be found in ____________
Amber is a form of tree resin—exuded as a protective mechanism against
disease and insect infestation—that has hardened and been preserved in the
earth’s crust for millions of years
C. Age of a fossil
i. Relative Dating
1. ____________ fossils are in _____________ layers
2. paleontologists can compare fossils with that of older fossils
ii. Radiometric Dating
1. Use of ____________________________ in rocks to date fossils
2. The technology of radiometric dating provides evidence that the earth is at least
______________________ years old
3. Certain elements convert to other elements at known rates, which can be
measured, thus revealing the age of the specimen
4. One half Potassium40 decays to Argon40 in about 1.3 billion years
5. Carbon 14 decays to half of its original amount in 5730 years
Common Isotopes used to date Geologic Materials
Parent Daughter T (1/2)
Era
Mesozoic
Cenozoic
II.
206 Pb
4.47 b.y
235 U
207 Pb
707 m.y
Type of
material
>10 millions
Igneous &
sometimes
metamorphic
rocks and
minerals
232Th
208Pb
14 b.y
40 K
40Ar & 40Ca
1.28 b.y
>10,000
years
87 Rb
87Sr
48 b.y
>10 million
years
147Sm
143Nd
106 b.y
14 C
14 N
5,730 y
Period
Precambrian
Paleozoic
238 U
Useful
range
100-70,000
years
Million
Years Ago
3500
3000
2000
Cambrian
540
Ordovician
510
Silurian
439
Devonian
408
Carboniferous 362
Permian
290
Triassic
245
Jurassic
208
Cretaceous
146
Tertiary
66
Quaternary
1.8
Organic
material
Major Events
Life evolves
First dinosaurs
First birds
Major Life Forms
Photosynthetic bacteria
Prokaryotes
Eukaryotes
Invertebrates
First Invertebrates
First land plants
First Amphibians
First reptile
Conifers dominant
First mammals
First flowering plants
Dominant flowering plants
Humans
Origins of Life
A. Origins: The Early Ideas
i. _______________________—non-living material can produce life
ii. Disproved by_________: experiment meat and maggots
iii. Disproved by Pasteur—S flask experiment
1. boils broth in S flask
2. broth is free of microorganisms for a year
3. removes curved neck
4. broth is “teeming” with microorganisms
iv. _________________—living comes from living things.
B. Modern Ideas
i. ________—suggested sun, lightning, and molecules such as water vapor, carbon
dioxide, nitrogen, methane and ammonia formed a “______________” that was
the beginning of simple organic molecules
ii. _______________________—1953-1954
1. Tried to answer the question by simulating conditions on the early Earth
2. Filled flask with hydrogen, ammonia, methane, and water = _____________
3. They passed electric sparks through the mixture to simulate _____________
4. Within a few days amino acids were present—the building blocks of ________
iii. _____________—showed how sort chains of amino acids could cluster to form
protocells
iv. Experiments like Miller and Urey's are currently studied at major universities
C. Evolution of Cells
i. First true cells—were probably ___________, ____________ and _________
1. prokaryotic: single celled—____________
2. heterotrophic: ___________ food for energy
3. anaerobic: did _______________ to survive
ii. Then came _____________________ organisms
iii. Then ___________—were probably archaebacteria that live in harsh
environments
iv. Next came photosynthetic prokaryotes—______________ into atmosphere
v. _________________ theory
1. Proposes that eukaryotic cells arose from living communities formed by
prokaryotic organisms—Lynn Margulis of Boston University
a. _____________ and ___________ contain DNA similar to
bacterial DNA.
b. Mitochondria and chloroplasts have ribosomes whose size and
structure resemble those of bacteria
c. Like bacteria, mitochondria and chloroplasts reproduce through
________________
d. Eukaryotic cells evolved from prokaryotic cells
2. ____________ = into; _________________ = relationship of two
organisms living close together
3. In summary: according to the theory of endosymbiosis eukaryotic cells evolved
when aerobic eubacteria either infected were engulfed by a larger host cell and
later established a symbiotic relationship
III.
Natural Selection and Evidence for Evolution
A. Charles Darwin—credited with the Theory of Evolution
i. Scientists, including Darwin, used fossils to explain that organisms have changed
over time
ii. Darwin and ________________
1. At age 22, Darwin sailed around the world, trip took 5 years
2. Ship’s naturalist—he collected specimens and note of the diversity he saw
iii. Darwin in the _______________
1. Group of islands off the coast of South America
2. Noted that the animals were unique but similar to the species he had seen
elsewhere
3. ________________ had differences in shell depending on which island they
inhabited
4. __________________ could swim and eat algae
5. _____________ had many different size beaks depending on the type of food
they ate
iv. Darwin Continues his Studies
1. ___________ proposed a theory about evolution in the year Darwin was born
called Use and Disuse Theory
a. Proposed that by selective use or disuse of organs, organisms acquired
or lost certain traits during their lifetime
b. These acquired traits then could be passed on to their offspring
2. Darwin continued to look for explanations to evolution for the next 22 years
3. He read about Thomas Malthus’ study which stated that the ____________
_________________________—Darwin applied this idea to all of life
4. Darwin also gained insight by ________________ using artificial selection
a. Breeders determine which individuals to use for breeding based on the
natural variation
b. Are able to produce a wide range of plants and animals that looked very
different from their ancestors
v. Darwin Explains Natural Selection
1. Natural selection is a ____________ that occurs when organisms with
certain variations survive, reproduce and pass on their variations to the next
generation
2. At this time, ___________ also reached similar conclusion
3. Darwin wrote a book, “On the Origin of Species” which today is still a unifying
theme of biology
a. There is ________________ among population
b. There is an ______________________ of offspring
c. There is a ___________________, competition for food and
shelter
d. The ___________________ and ______________
e. Heritable variations are passed onto offspring
f. Giving way to “________________________________”
vi. Interpreting Evidence After Darwin
1. Modern biologists define evolution as ____________________________
___________________________
a. gene pool is the combined genetic information of all the members of a
population
B. Three Types of Natural Selection
i. __________________
1. Favors individuals possessing extreme values of a trait, which causes the
population to move in a particular direction
a. If a climate becomes colder, a population may evolve in a consistent
direction in response—thicker fur
ii. ___________________
1. Acts against individuals who deviate too far from the average, favors the
average
a. Sizes in lizards: large lizards may be subject to predation; small lizards
may have a hard time defending territories, natural selection favors the
average
iii. __________________
1. Adapts individuals in a population to different habitats.
2. Similar to directional selection—but it favors either extreme
3. May occur in an area that provides very different resources
a. Galapagos finches had a variety of food choices: smaller birds fed on
small seeds, larger birds feed on large seeds. Natural selection favors
both but not the average who would compete for both resources.
C. Evidence for Evolution
i. _______________________
1. not all species existed ______________________
2. fossil record is fully consistent with the prediction that more "derived" groups
should appear over time in the fossil record
3. there has not been a single case of a species out of order--no mammals mixed in
the rock with early fish
4. life began in the sea. The oldest fossils are marine
5. _________________ between major groups (classes) of species
fish-->amphibians (transition from ray-finned fish to tetrapods)
reptiles-->birds (Archaeopteryx)
reptiles-->mammals (synapsid reptiles (therapsids) have very mammalians
characteristics)
6. transitions between classes (ex. orders of mammals)
7. well preserved family groups (horse family)
8. well preserved communities of species that no longer exist but resemble modern
species
ii. ______________________________
1. species that existed in the past are fossilized in areas where species that resemble
them are living now
2. ______________________________
a. organisms that live under similar ecological conditions are exposed to
similar pressures of natural selection
b. because of similar selection pressures, different animals end up evolving
certain striking features in common
iii. ______________________: gradual change in an organism that enables it to
survive in a particular environment
a. _____________ adaptations
i.
___________ of an organism like the bill on a bird, the fur on
bear, stinging cells of jellyfish or sticky tongue of an anteater
ii.
________________ (HSS): structures that have different
mature forms in different organisms but develop
exist among related groups, providing support for having a
common ancestor
iii.
___________________(ASF): outwardly similar structures
iv.
_____________ (NF): structure that serve no useful function
in an organism (ex. pelvic bones in pythons; blind salamanders)
b.________________ adaptations
i.
things organisms ____________________.
ii.
Ex. bird calls and migration
c. __________________ adaptations
i.
______________ within the cell, or tissue of an organism in
response to an environmental stimulus, resulting in the
improved ability of that organism to cope with its changing
environment
ii.
physiological adaptations can develop rapidly
iii.
Ex. digestive enzymes, hemoglobin, bioluminescence
iv. _________________
1. during the early stages of development many animals with backbones are so
similar that they can be hard to tell apart (share "Hox" genes)
2. embryonic development shows that the same group of embryonic cells develop
in the same order and in similar patterns to produce tissues and organs of
all vertebrates
v. _______________________________
1. fields unknown during Darwin's time ________________ made from his
theory and provide independent evidence that is congruent with the fossil
record
2. all organisms share the same genetic code which codes for amino acids that make
up proteins
3. ____________ that help an organism survive its environment are passed on to
the next generation.
4. Species that diverged longer ago have more differences in their
corresponding proteins. (just like comparing how closely related two humans
are, one can compare how related different species are.)
5. EX. DNA comparisons, ATP, proteins
IV.
Mechanisms of Evolution
A. Population Genetics
i. POPULATIONS, not individuals, EVOLVE
1. _______________—all of alleles of population’s genes
2. Allelic (gene) frequency--% of specific allele in gene pool
3. _________________—gene frequency remains constant over many
generations (not evolving)
ii. Changes in Genetic Equilibrium
1. Mechanisms for genetic change
a. __________—environmental factors or chance
b. sexual reproduction
c. ___________________ is the most significant factor to cause
change in a gene pool
d. ______________*—when individuals enter or leave a population
i. Immigration-individuals moving INTO a population
ii. Emmigration-individuals moving OUT of a population
*Examples of Gene Flow
1. ___________________:
a. occurs in small populations that become isolated like animals in the
Galapagos
b. in each generation, some individuals may, just by chance, leave
behind a few more descendents (genes) than other individuals
c. the _______ of the next generation will be the genes of the "lucky"
individuals, not necessarily the healthier or "better fit"
individuals
d. it happens to all populations-there is no avoiding the vagaries of
chance
e. can cause big losses of genetic variation for small populations
i. _______________: when a population's size is reduced for
at least one generation--causing reduced genetic
variation
ii. ______________: occurs when a new colony is started by
a few members of the original population--reduced genetic
variation/non-random sample of the genes in the original
population
V. Evolution of Species: Speciation (formation of a new species)
A. ___________________________
i. __________________________ physically isolates populations of a species
which blocks gene flow
ii. once isolated allopatric populations (living in different places) accumulate genetic
differences due to natural selection, genetic drift, and new mutations
iii. removing the geographic barrier---the following could happen:
a. meld together by allele flow and
b. recombination once again to form a single
species;
c. remain reproductively isolated—pre-mating or post-mating isolating
mechanisms-- different types of reproductive isolation
B. ________________________ (does not involve a geographic barrier)
i.
results from _______________________ such as chromosomal changes and
non-random mating
ii. become genetically isolated even though their ranges overlap
ex. polyploidy, non-random mating
iii. change in Chromosome Numbers and Speciation
Ex. Polyploidy—more than a normal set of chromosomes.
C. _____________________—interbreeding organisms can no longer mate and produce
fertile offspring
i.
Genetic material very different so fertilization doesn’t occur
ii. Behavioral—mating at different times of day/month/year
iii. Different pheromones
iv. _________________—physical differences prevent mating between species
VI. Pacing of Evolution
A. ________________—fossil evidence shows this
i. explanation that evolution involves a slow and steady accumulation of changes over a
period of time
B. _________________—occurs relatively quickly, in rapid bursts, with long periods of
genetic equilibrium in between
i. Pattern of long, stable periods of stasis (no change) interrupted by brief periods of
rapid evolution
VII. Patterns of Evolution
A. ____________________
i. Two different species develop ____________________ because they live in similar
environments
ii. For example—ability to move through the water rapidly—shark (fish), penguin (bird),
and dolphin (mammal)
iii. Species evolve to fill niches; mutations occur randomly in geographically distinct
populations; natural selection allows the mutations that "work" to become
adaptations
B. ____________________
i. Occurs when a population becomes isolated from the rest of the species and begins
to follow a different evolutionary course
1. often results in ___________________________
2. associated with the opening up of a new biological frontier
ii. For example—Darwin’s finches which had different beak lengths
C. ___________________
i. Two different species evolved at the same time because of a beneficial relationship
between the two groups