Pre-AP Biology - Evolution Review - KEY
Microevolution
1. Explain what each scientist below did that was significant to the Theory of Evolution.
 Redi – Did experiment showing that maggots come from flies and not from meet
o Remember: Redi = Red meat
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Needham- Tried to PROVE spontaneous generation (only guy who did that)
o Boiled broth in a flask and WAITED TO COVER IT UP until after it had cooled (that was
the problem with his experiment)
o bacteria entered flask as it cooled
o Saw bacteria return to flask
o Thought this proved spontaneous generation
 Remember = Needham “needs” to get a better experiment
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Spallanzani – Did basically the same experiment as Needham but was trying to disprove
spontaneous generation
o Difference was that he covered up the flask immediately so no bacteria came back
o People argued that he killed the “life force” of the air so they didn’t accept his results
 Remember his as the “air murderer”
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Pasteur – Did same experiment as Needham and Spallanzani but came up with a flask that
allowed AIR TO ENTER BUT BACTERIA COULD NOT
o This set up would’ve allowed the “life force” of the air to reenter
o Still, there were no bacteria that returned to the flask
o Proved biogenesis to be true (and spontaneous generation to be false) once and for all
 Pasteur = put spontaneous generation in the “past”
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Malthus - Gave Darwin idea that populations produce more offspring than can survive
because populations increase faster than earth can support
This would mean that natural selection would be “the survival of the fittest” because there
were not enough resources for every organism to survive.
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Wallace – Came up with idea of correct idea of evolution at same time as Darwin but Darwin
published his book first
**** Is not on your paper - Hutton – Theory of Gradualism – Way to remember: Hutton said the
world was “puttin’” along
**** Is not on your paper - Cuvier – Theory of Catastrophism – leads to punctuated equilibrium
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Lamarck – Believed in Evolution (populations change over time) before Darwin, but his ideas
on how it worked were wrong.
1. Simple forms of life eventually develop into more complex forms
2. Inheritance of Acquired Characteristics by Means of Use or Disuse (Traits gained in life
by experience or behavior could be passed on to offspring)
(Ex. Bodybuilder parents
Bodybuilder baby)
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Lyell – Theory of Uniformitarianism: Said that geologic change takes LONG PERIODS OF TIME;
Darwin took that to mean that Biological change (evolution) would also occur over extremely
long periods of time
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Miller and Urey – Did experiment trying to show how the first cells could have been formed
(Lightning experiment) – Tried to show how life began (CHEMICAL EVOLUTION)
NO O2
2. What is spontaneous generation? Life can come from non-living things
3. What is the biological definition of evolution? A scientific theory that states that living species
are descendants of ancestral species that were different from present day ones (the genetic
changes in a population over generations)
4. What is the gene pool of a population? All the genes in a population; EVOLUTION OCCURS
WHEN A POPULATION’S GENE POOL CHANGES.
5. What was the name of Darwin’s book? On the Origin of Species by Means of Natural Selection
6. Discuss Darwin’s principle of survival of the fittest and explain what Darwin meant by natural
selection.
The process by which organisms best suited to the environment survive, reproduce, and pass their
genes to the next generation.
Fitness -(1) Survive Longer, (2) Reproduce More
(3) Pass on traits to next generation
Occurs in populations, not in individuals
a. Note: It is not essential to survive longer. The longer life simply gives more time to
produce more offspring. Ex. Evolution would favor someone who was 20 and had 4
kids rather than someone who is 80 with 1 kid.
7. Contrast Lamarck’s and Darwin’s ideas about changes in organisms over time.
8. Give the steps that are required for natural selection to occur.
Organisms produce more offspring than can survive.
Genetic Variation - Individual organisms in a population have slight variations or adaptations
(WORD MEANING??).
Individuals struggle to survive, those with adaptations best suited to the environment are
more likely to survive.
Survivors pass on genes for the adaptations to their offspring.
Gradually, the population’s gene pool changes and the population evolves.
9. For each of the following types of natural selection include 3 pieces of information: a) what
phenotypes are chosen against, b) what does the resulting population look like after the selection,
c) draw a graph showing what the population would look like before selection and after selection
 Stabilizing
Selection against the extreme phenotypes (physical type)
This causes average phenotype to become much more common (the look of the population is very
similar and average)
Ex. Human weight at birth
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Directional Selection
favors one extreme phenotype (physical type)
This causes this particular extreme phenotype to become much more common (the look of the
population is pushed in 1 direction)
Ex. Peppered Moths
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Disruptive/Diversifying
Selection that favors both extreme phenotypes (physical type)
This causes extreme phenotypes to become much more common (the look of the population shows
extreme differences)
Ex. Darwin’s Finches
10. What is artificial selection?
Evolution that occurs because of human interference (the evolution is “artificial”)
Ex. Dogs or crops
11. What is convergent evolution, and what are analogous structures?
These species do NOT have a common ancestor. They have merely evolved to look similar.
Convergent evolution – process by which different species evolve similar traits
(SAME FUNCTION, DIFFERENT ANCESTOR)
Example: Birds, bats, and moths have wings, but they did not evolve from a recent common
ancestor.
 Caused by:
◦ living in similar habitats / performing similar functions
Analogous Structures:
 Structures with closely related function but do not come from the same ancestral structure
◦ Same function, different structure
 Example: Birds, bats, and moths have wings, but they did not evolve from each other.
a. How is convergent evolution different from divergent evolution?
Convergent evolution causes organisms that DO NOT have a common ancestor to appear
similar (have analogous structures). Divergent evolution causes that DO have a common
ancestor to appear different.
12. Explain how each of the following gives evidence that supports evolution.
 Fossils- We can see the change in a population over time through the fossils; Can also use
relative dating (strata) and absolute dating (carbon dating in fossils) to see what time period
the species were alive
 Homologous structures – Ex. Whale fin, Human hand, Cat paw, and Bat wing
Divergent evolution- build up of differences between groups which can lead to the development of a
new species
 In other words, two different species that evolved from the same ancestor.
 Caused by populations of the same species:
1. moving to two different environments or..
2. specializing in different areas of the same environment
Homologous Structures:
 Structures in different species that originated from common ancestor
 May have different function but similar structure
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Molecular Biology (DNA and amino acid sequences - proteins) – Note: This is the most
important type of evidence proving evolution.
The closer 2 different species DNA is to one another, then the closer those 2 are related.
All living things use DNA and RNA.
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The genetic code amongst all living things is universally the same. (In other words, the fact
that the RNA codon AUG gives the amino acid MET in humans is seen in every other living
thing as well)
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Vestigial structures
Structures that once had a use but no longer are used (they are still present because there is
no evolutionary selection against having them)
Biogeography
study of the distribution of species and ecosystems in geographic space and through
geological time.
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13. Genetic variation creates biodiversity (the differences in all living things). Explain how the
following things provide the biodiversity that evolution can then act upon.
 Mutations!!
 Mutations are a change in a gene that results in a different protein (and therefore a different
phenotype). This is how all new traits come about. If this new trait is beneficial then that
individual will survive longer and reproduce more than the rest of the population, and the
population will evolve to have this trait.
 Type of mutations
o Point Mutations (base substitution)
o Reading frameshift (insertion or deletion)
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Sexual Reproduction (Use the terms crossing over, segregation, and random fertilization)
1) Crossing Over – DNA of nonsister chromatids exchange during prophase 1 (so every
chromosome is different)
2) Independent Assortment – Homologous chromosome pairs line up independently of each
other during metaphase I (so each sperm / egg receives a different set of chromosomes)
3) Random fertilization – every sperm/egg is different and it is random as to which sperm
fertilizes an egg to create a zygote
14. Which type of mutations matter in evolution: mutations in somatic cells or mutations in gametes.
Why?
Gametes – Evolution is in a population over many generations (no 1 person has ever
evolved). So, a mutation in a gamete would be passed to the next generation. Because that
individual had a mutation in their first cell, every single cell in their body would show the
mutation and it could continue to be passed on. Mutations to somatic cells would only affect
that 1 area and could not be passed on to offspring (so would not matter in evolution).
15. Hardy-Weinberg equilibrium allows us to study if a population’s gene pool is changing from
generation to generation. There are 5 rules that must be followed for a population to stay in
equilibrium (or in other words, if you break any of these rules then the population will evolve.
Once again, these would be the 5 things that would cause evolution.) List the 5 rules of HardyWeinberg and explain why breaking each of them would cause evolution to occur.
a. Very large population (so no genetic drift)
i. Bottleneck effect
ii. Founder effect
b. No gene flow between populations (so no introduction of new alleles)
c. No mutations (so no introduction of new alleles)
d. Random mating (so 1 phenotype cannot reproduce at a greater rate than others)
e. No natural selection (so 1 phenotype does not survive longer than others)
16. If a population is in Hardy-Weinberg equilibrium, what happens to the frequencies of the alleles
and the genotypes present in the population change generation and generation?
Allele frequencies and genotype frequencies remain constant (because population is in
equilibrium)
17. What is the equation for allele frequencies in Hardy-Weinberg equilibrium? Note: This is for the
ALLELES, not for the actual organisms themselves.
p+q=1
p= frequency of dominant allele
q = frequency of recessive allele
18. What is the equation for the genotype frequencies in Hardy-Weinberg equilibrium? Note: This is
the equation for the actual organisms.
p2 + 2pq + q2 = 100% = 1.0
p2 = frequency of homozygous dominant individuals
2pq = frequency of heterozygous individuals
q2 = frequency of homozygous individuals
19. A population of snakes is in Hardy-Weinberg equilibrium. A dominant allele for skin color makes
the snake black while the recessive allele makes them albino. A sample of 100 snakes was taken
from a population. Of the 100 snakes captured, 75 of them were black and 25 were white. What
percentage of the 100 snakes would be expected to be heterozygous? (Hint: Steps to do this
problem. 1. Find the percentage of the recessive allele (q) from the number of homozygous
recessive (q2), 2. Find the percentage of the dominant allele (p) by plugging calculate
number of heterozygotes by plugging the allele frequencies into the proper location in the
genotype frequency equation.)
1) 25 / 100 = white which means they are homozygous recessive
^^ because of this q2 = 0.25
2) p + q = 1
p + 0.25 = 1
p = 0.75
3) p2 + 2pq + q2 = 1
(0.75)2 + 2(0.75)(0.25) + (0.25)2 = 1
20. the frequency of the q allele into the allele frequency equation. 3. Now use these 2 allele
frequencies to p2 (homozygous dominant) = 56%
2pq (heterozygous) = 37%
q2 (homozygous recessive) = 6%
21. What is sexual dimorphism?
Di = 2 and morph = shape
This means males and females look differently
Like peacocks, humans, deer
22. What is coevolution?
2 species having a symbiotic relationship and evolving together
Macroevolution – This information can be found in Ch. 14 and 15 of the textbook.
1. There are several different ways to define a “species” (we most commonly use the biological
species concept). Below, the biological species concept (which is the most common way to
define a species). Pgs 278 -279
a. Biological species concept (be sure to include reproductive isolation in this explanation) –
Can interbreed and produce viable, fertile offspring.
Reproductive isolation prevents gene flow between species. (Not useful for fossils or prokaryote
(asexual reproduction).
b. What is a scenario where using this type of species concept would not work?
Fossils, asexual reproducing organisms
2. Explain how new species are created through allopatric speciation. Pg 282
Separation of species (with its gene pool) from other populations (geographic isolation)
No gene flow (no movement of alleles between the 2 species because of the geographic
isolation)
Mutations accumulate between the 2 species making them increasingly different. Eventually,
their DNA is so different they can no longer reproduce.
3. Sympatric speciation is similar to allopatric speciation in that new species are created. Even so,
sympatric speciation occur without a geographic barrier. There is still no gene flow between the
2 populations due to reproductive isolation by either prezygotic or postzygotic barriers. Define
and give an example of a prezygotic and postzygotic barrier.
a. prezygotic barrier – Reproductive barrier that keeps the zygote from being formed
b. postzygotic barrier – Problem that occurs after the zygote is formed
4. Describe what is meant by adaptive radiation and give examples of when this type of evolution
would occur. Pg. 288
Evolution of many diverse species from one common ancestor- Like Darwin’s Finches
Typically when few organisms occupy new area, start filling up available niches
5. Explain the following modes of evolution. Pg. 289 – realize that both of these models are true in
different instances
Punctuated equilibrium – long periods of no change, rapid change after catastrophism
Gradualism – things change slowly, incrementally over time
6. What is catastrophism, and how could it cause punctuated equilibrium to occur?
Catastrophism – theory that many of the Earth’s features have been affected by cataclysmic
events that have in a sense “scarred” the Earth and killed most of the occupants on it. (Ex.
Dinosaur extinction coincided with asteroid hitting the Earth. The impact and heat killed most
organisms. The surviving organisms adapted to new, remaining food sources to survive.
Punctuated equilibrium will then describe what happens to the surviving species)
7. Answer the following questions concerning character tables.
a. What goes on top and how is it listed (oldest to youngest or youngest to oldest)?
Organisms from oldest to youngest
b. What goes on the side and how is it listed (oldest to youngest or youngest to oldest)?
Traits from youngest up top to oldest at the bottom
8. What is a cladogram, and what is it used for?
Graph showing evolutionary timeline; To show the common ancestors of species that have
experienced divergent evolution
9. What evidence for shared ancestry can be used to make a cladogram? (What things can you use
to make a cladogram?)
DNA, proteins, fossils, etc.
10. Use the cladogram below to answer the following questions.
a. What is the dragonfly most related to? Butterfly
b. What is the most recent common ancestor of the grasshopper and the spider? C
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11. Describe the conditions of Early Earth. Pg. 294
Thick with water vapor and compounds released by volcanoes
Cooled and water vapor became oceans
NO OXYGEN
Photosynthesis was complex..so it took awhile for these organisms to occur
12. What did Stanley Miller and Harold Urey do in their experiment, and what did their results
show? Pg. 295
Showed that amino acids and other organic molecules could be formed under conditions
believed to simulate those of early Earth
Lack of Oxygen allowed creation (O is oxidizing agent and disrupts chemical bonds)
Created early earth environment and showed that lightning could create life
Early environment now not believed to have been composed of same compounds used in
Miller’s experiment
13. Define autotroph and heterotroph.
autotrophs make their own food and heterotrophs must consume their food
a. Hypothesize why early autotrophs had an advantage over early heterotrophs.
There was very little food available. The ability to make one’s own food saved energy from trying to
find food and prevented starvation.
14. Differentiate between physical evolution and behavioral evolution (talk about migration and
courtship rituals while describing behavioral evolution).
Physical evolution is what we have talked about so far (physical changes seen in populations
over generations).
Behavioral evolution is the changes seen in behavior in populations over generations. These
behaviors are seen because they increase survival and reproductive rates. For example, birds
that migrate during the winter survive to reproduce while those that do not die. Courtship
rituals show that males who perform certain acts are allowed to reproduce more and pass
their traits on at a greater rate.
15. Differentiate among chemical evolution and organic evolution.
Chemical evolution is how life began (how did we go from just chemicals to life..explained by
Miller and Urey)
Organic evolution is the evolution of living things (what we have discussed basically the entire
time)
Aerobic heterotrophs (consumers who use oxygen) and photosynthetic autotrophs – There
was no oxygen in the environment until the first photosynthetic organisms. After their arrival,
there was lots of oxygen. Mutations to heterotrophs allowed them to be able to use this
oxygen to create much more ATP than they had been able to in this past. This allowed them to
survive longer and reproduce more than anaerobic heterotrophs.
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Things to add for taboo cards
o Polyploidy