Biology 1
Evolution
NAME:
The Guiding Questions
PERIOD:
 What is the process by which populations of organisms
change over time?
 Why is there such a great variety of life on Earth?
Learning Outcomes
By the end of this topic, you should be able to:
 Understand that organisms vary, and that some heritable variations give advantages over others in
the “struggle for existence”.
 Describe the work of Charles Darwin and Alfred Wallace.
 Compare environmental and genetic mutation. Know that mutation is a rare, random change in
genetic material that can be inherited and they can be harmful, neutral or beneficial.
 Identify the role of variation in species survival under changing environmental conditions.
 Explain that variations caused by genes/alleles can be passed onto offspring, and that genes with
advantageous adaptations are more likely to be passed on than others.
 Describe the process of evolution by means of natural selection.
 Examine the evidence for evolution by natural selection.
 Describe observed examples of evolution, including the evolution of drug-resistant bacteria and
sickle-cell anemia in Coastal West Africa.
 Distinguish between processes leading to speciation, including geographical isolation (Wallace’s
line) and adaptive radiation (Galapagos Islands).
 Understand the concept of a common ancestry/origin in species formation, and describe evidence
of common ancestry.
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Vocabulary Pages.
By the end of this topic, you should be able to define and correctly use the
following terms:
Populations
Gene
Allele
Variation
Adaptation
Mutation
fitness
pressure
natural selection
evolution
homologous structures
analogous structures
vestigial structures
speciation
Geographical isolation
Adaptive radiation
Artificial selection
Common ancestry
Convergent Evolution
Species
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Evolution
1.
Who is CHARLES DARWIN and what did he do? What was his work with FINCHES about?
2. Who was Alfred Wallace and what was his work about?
3. What are the major points of Darwin and Wallace’s theory of evolution through natural selection?
#1.
#2.
#3.
#4.
#5.
#6.
#7.
What is the difference between evolution and natural selection?
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4. What is biological VARIATION? What role does variation play in the mechanism of natural
selection?
5. How does Natural Selection lead to changes in populations over time?
6. What does it mean for a population to “evolve”? Can individuals “evolve” in this sense?
6. Conduct some research and explain evolution in action for
the following examples:
a.) Example: Drug-Resistant Bacteria
b.) Example: Sickle Cell Anemia and Malaria in Coastal West Africa
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Evolution
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“Evidence for Evolution”
A. Artificial Selection
1. How are artificial selection and natural selection different?
2. How does artificial selection provide support for the theories of natural selection and evolution?
B. Fossil Evidence
1. What are fossils, and how do they get where they are found?
2. What do fossils show us about evolution of organisms?
3. Why are there no dinosaur fossils dated later than 64 million years
ago?
4. About the same time there was an increase in the number and kinds of mammal fossils. Explain.
C. Biogeography
1. How does biogeography provide evidence for evolution?
2. What is Wallace’s Line?
D. Comparative Anatomy
1. How is the study of embryos further evidence for evolution?
2. What is a homologous structure? Give an example
.
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Evolution
3. What is an analogous structure? Give an example.
4. What is a vestigial structure? Give an example.
5. How do these structures provide evidence for evolution?
What is meant by “Convergent Evolution”?
E. Biochemistry
1. How does the ‘cytochrome c’ protein in organisms change with the increased differences in an
organism? How about hemoglobin?
2. DNA Sequencing
Why is DNA sequence considered a better source of information about evolution (for closely related
species) than looking at a protein sequence?
F. Directly Observed Evolution
1. How is the history of bacteria and antibiotics an example of observed evolution?
2. Apply our discussion of evolution of resistance to antibiotics in bacteria, to the effect on insects
(like cotton weevils) of intense spraying of antibiotics?
3. What are some conditions that are likely to lead to rapid (and therefore observable) evolution?
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Convergent Evolution and Analogous Features:
How can new species develop?? (called Speciation)
Geographic Isolation – Wallace’s Line:
Divergent Evolution
Adaptive Radiation – Galapagos Islands:
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Evolution Video Series: Evolutionary Arms Race
1. What is Russia’s new enemy?
2. How poisonous in the rough-skinned newt?
3. What can eat the newt safely?
4. How do scientists measure the effect of newt toxin on snakes?
***Watch the cool examples of predation!***
5. What is the major predator of humans today?
6. What are some examples of major human predators?
7. What do antibiotics do?
8. How is TB (tuberculosis) transmitted?
9. What happened to Sasha after he stopped taking medicine?
10. If second line drugs cause side-effects why do people take them?
11. What are Anna’s chances of surviving the infection?
12. How many people TB each year?
13. Why is the race between humans and bacteria endless?
14. What kinds of circumstances are likely to make diseases mild or severe?
15. How could an understanding of evolution help protect humans against disease?
16. What does feline immunodeficiency virus (FIV) cause in house cats?
17. What symptoms does FIV cause in wild cats? Why is it different than in house cats?
18. How are some humans protected against HIV infection?
19. Name a mutualistic symbiotic relationship between two species.
20. Describe the relationship between leaf-cutter ants, leaves, fungi, and mold.
21. What is the difference between children’s immune systems on farms v. in cities?
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Evolution Video Series: Extinction!
1. What is extinction?
2. What is the average lifespan of a species?
3. What clues about past life are found in Permian rocks?
4. What differences are seen in fossils at the end of the Permian v. the start of the Triassic?
5. What was the % chance that a species in the Permian would survive into the Triassic?
6. What were the first mammals like and how big were they?
7. What adaptations did mammals evolve while living with the dinosaurs?
8. What happened on Earth 65 MYA?
9. How has human civilization affected the global extinction rate?
10. What is empty forest syndrome?
11. Why do scientists count carnivores in order to measure the health of an ecosystem?
12. What is the story of the Siamese crocodile?
13. What happens to the cameras and what does it mean?
14. What is the #1 cause of extinction?
15. What is the #2 cause of extinction?
16. How did Polynesian colonists change Hawaiian ecology?
17. What is ballast water and why is it a problem?
18. What happened to Guam’s native birds?
19. EXPLAIN how the “house of cards” analogy applies to today’s situation?
20. What is the problem with leafy spurge?
21. What are two ways that leafy spurge be fought? Which seems to work better?
22. Is the Kaeng Krachan National Park in Thailand still doing well? What is the evidence?
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Evolution
Evolution Video Series: Great Transformations
1. When did some mammals go from the land to the sea?
2. If the age of the Earth is represented by an hour, when did animals appear? Human civilization?
3. What was exciting about the skull Phil Gingrich found in Pakistan?
4. When war shut Pakistan’s borders, what surprising place did Gingrich find whale fossils?
5. What was the Valley of the Whales like when the whales were alive?
6. What feature did Gingrich find on the whale Basilosaurus?
7. By looking at the transitional species, what can we see about whale nostrils?
8. How is fish swimming different from mammal swimming?
9. What feature did the ancestor of mammals have?
10. Which came first, living on land or legs?
11. How are a 370 million-year-old fin and a human arm the same?
12. When did animals start to appear?
13. What is special about the fossils in the Burgess Shale?
14. What is the raw material that evolution works with?
15. What type of bug does Levine study and why?
16. How did scientists cause mutations in flies?
17. What did the antennapedia gene do?
18. What do all animals have in common?
19. What change was crucial to set us apart from other primates?
20. How do lemurs move?
21. Did we evolve from chimps?
22. What are 2 differences between human and chimp skeletons?
1.
2.
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Evolution
Data Management Practice!
Daylength to enter hibernation / hr
1. A mosquito species has a genetically controlled response to daylength. At longer
daylengths, mosquitoes develop and try to lay eggs, whereas shorter daylengths lead to hibernation.
In the northern regions of the northern hemisphere, even though daylengths are longer, winter arrives
earlier than in regions closer to the equator.
The following data is from an experiment to determine if these mosquitoes have adapted to
later onsets of winter as a consequence of global warming. In 1972 and 1996, mosquitoes were
collected at various locations in the United States at latitudes 30–50° North. The mosquitoes were
examined to determine what daylength induced hibernation.
Each circle on the following graph represents one larval population.
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15
1972
14
1996
13
12
30
35
Equator
40 45
Latitude /º
50
55
North Pole
[Source: Bradshaw and Holzapfel, Proceedings of the National Academy of Sciences of USA, (2001),98 (25), pages 14509–14511]
(a)
(b)
In 1972, what daylength is required to cause hibernation
i. at 35° latitude:
_____________________________________________
ii. at 45° latitude:
_____________________________________________
Outline the relationship between daylength and latitude for the mosquito populations in 1972.
.................................................................................................................................................................................
.............................................................................................................................................................................(2)
(c)
Compare the data of 1972 with 1996.
.................................................................................................................................................................................
........................................................................................................................................................................... (2)
(c)
Explain how the data illustrates an evolutionary response to a longer growing season due to a
later onset of winter.
...............................................................................................................................................................................
...............................................................................................................................................................................
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2. The peppered moth exists in two forms, the normal light coloured form and a dark melanic form.
Studies were carried out in West Kirby, England to see if changes in the level of smoke pollution
affected the frequency of the dark melanic moths. The graph below compares the percentage of moths
that were melanic with the annual winter level of smoke.
Key:
frequency of moths
annual average winter levels of smoke
100
90
80
70
Percentage of
melanic moths
300
60
50
200
smoke /
gm -3
40
30
100
20
1960
1970
1980
Time / year
1990
[Source adapted from: Colin Patterson (1999), Evolution]
(a) In 1965, state
i. the percentage of melanic moths:
ii. the level of smoke:
.............................................................(1)
.............................................................(1)
(b) Identify two consecutive years of increased smoke pollution:
…………………….…………………………………. (1)
(c) Suggest a reason for the increase in smoke pollution from 1966 to 1968.
……………………................................................................................................................................................ (1)
(d) Compare the change in the percentage of melanic forms of moth with the changes in smoke in the
air.
..................................................................................................................................................................................
.............................................................................................................................................................................(2)
(e)
Discuss whether the data shows evidence for evolution.
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Evolution Misconceptions Diagnostic
Adapted from http://evolution.berkeley.edu/evolibrary/misconceptions_teacherfaq.php
1) A volcano erupted on an island. The ash released from the volcano changed the acidity (pH) of the
soil from the level it had been for hundreds of years. This significant change resulted in new
environmental pressures on species in the soil. Which of the following is a likely outcome of these
pressures?
a) Some species will disappear from the soil because they do not have individuals with traits that allow
them to survive in more acidic soil.
b) Only some species will generate the needed mutations to adapt to the change in pH; other species
will become extinct.
c) Most species gain additional genetically-based traits, and this increase in complexity allows them to
live in the more acidic soil.
d) Individuals in each species will evolve the traits necessary to survive under these new conditions.
2) A ship that had been used for many years in arctic exploration was sold and moved to a harbor in
the warm waters of the Caribbean. Worms that had lived on the ship bottom crawled off in the warm
waters and attempted to attach to other ships in this tropical area where there were no similar worms.
Some of the worms were able to survive and reproduce. What would you expect to happen to this
group of worms over many generations in this new environment?
a) The worms will mate and produce offspring just as they did in their previous environment, and the
group’s traits will likely remain unchanged after many generations.
b) The worms will gain new, more complex traits through natural selection that will help them better
adapt to the warmer waters because natural selection leads to more complex and better adapted
organisms.
c) Worms possessing genetic variations that help them to survive and thrive in the new environment
will leave more offspring than others lacking those traits. Over time, the proportion of the worm
population with these adaptive traits will likely increase.
d) The mutation rate will increase in this group of worms in order to promote evolution.
3) A scientist is studying a species of gopher found in North America. Some of the areas where these
gophers live and burrow have hard packed soil. Other areas contain soil that is more lightly packed and
loose, and still other areas contain both types of soil. The animals that live in the area with hard
packed soil have thick short claws. Those in the areas with more loosely packed soil have long thin
claws. There is wide variation in claw shape among animals living in areas where both types of soil exist.
Which statement best explains this distribution of gopher types?
a) Both the areas with hard packed soil and the areas with looser soil were colonized by animals from
the mixed soil area. The hard packed soil area happened to be colonized by animals that by chance had
thicker claws, and those with thinner longer claws happened to colonize the areas with less densely
packed soil.
b) Each type of environment was probably colonized by gophers with variation in claw type, but over
time each individual changed its traits to ones needed to live best in each area so all the gophers in the
hard packed soil had only the traits needed to live there and, similarly, because the gophers in the
loosely packed soil needed particular traits, they changed their traits to suit that environment.
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c) Animals with thick short claws are better able to burrow in dense soil, so in
hard packed soil areas those animals with thicker claws were better able to
survive and reproduce. In areas with loose soil, animals that thin long claws
better for moving larger amounts of soil were the ones most likely to survive and produce offspring.
d) The animals in the hard packed soil areas needed to have claws adapted to hard soil, so a mutation
arose to provide that trait. The animals in the less dense soil areas also needed to adapt, so they had a
mutation that made their claws suitable for soil in their area.
4) Bacillus thuringienses (Bt) bacteria produce a natural insecticide. Widespread use of Bt has lead to
Bt resistance among insects. Why is this occurring?
a) Individual insects that have mutations providing resistance to Bt can survive in the presence of Bt.
The survivors pass this Bt resistance on to their offspring.
b) Bt-resistant insects increase in the population by chance. There are so many insects that some of
them are resistant to each type of insecticide.
c) In the presence of Bt, individual insects evolve to become Bt resistant.
d) Natural selection causes insects to generate genes providing resistance to Bt.
5) A chef sprays antimicrobial cleaner on her counter top. At the first, the bacteria population
declines significantly. However, even though she continues to spray in following weeks, the number of
bacteria begins to increase again. Why did this happen?
a) Some bacteria had traits that allowed them to survive the initial antimicrobial application. They
produced offspring also carrying those traits.
b) After the application of antimicrobial spray, the bacteria needed to adapt by developing
antimicrobial spray-resistant traits.
c) The antimicrobial compound caused a mutation for resistance to it. This trait increased in the
population over time.
d) The bacteria that tried hardest to become resistant left more offspring, who were also resistant.
Misconceptions about Human Evolution
It is important to remember that:
1. Humans did not evolve from chimpanzees. Humans and chimpanzees are evolutionary cousins
and share a recent common ancestor that was neither chimpanzee nor human.
2. Humans are not “higher” or “more evolved” than other living species. Since our lineages split,
humans and chimpanzees have each evolved traits unique to our own species.
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Natural Selection Lab- PhET Simulation
You can download the simulation here:
http://phet.colorado.edu/en/simulation/natural-selection
Pre-Lab Questions
1. What variables can you influence in this lab?
2. Define what a genetic mutation is. How do genetic mutations
happen? How often?
3. What do the terms fitness and adaptation mean? What is the difference between the two?
4. What selection factors might effect an animal population besides the ones used in this lab?
Designing The Experiment
In this Lab you will be controlling the mutations and environment of a population of rabbits. Your
will create four hypotheses and design an experiment to test each one. Your hypothesis will follow
the format where you fill in the (...) with your own ideas and reasons.
I hypothesize that (select a rabbit phenotype) rabbits will be (more/ less) likely to survive
under (type of selective factor) within the (select type of environment) environment,
because..... (explain how their trait will help them to survive or not)
***You must make at least one hypothesis for each of the three different types of phenotype mutations***
For each experiment you must have a control (no mutation) and fill in the following chart
Experiment
and
Hypothesis
3.
4.
5.
Pheno
type
Selective
Factor
CONTROL
Group
Initial
Population
at F3
CONTROL
Group
Final
Population
Experiment
Group
Initial
Population
at F3
Experiment
Group
Final
Population
Conclusion/
Observation
For each of the experiments, begin by adding a friend and a mutation. Wait until the F3
generation before adding the selective factor. After adding the selective factor let the
simulation run for another 3 or 4 generations.
Use the population numbers from the chart to get you numbers for the table, remember you
can zoom in and out on the chart to get more accurate reads.
Repeat for experiments 2, 3 and 4
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1.
Post-Lab Questions
Based upon your evidence from the simulation what conclusion are you able to make about
each of the three different types of phenotypes in rabbits?
2.
What happens to animals that cannot compete as well with other animals in the wild?
3.
Sometimes animals that are introduced into an area that they never lived in before, outcompete and endanger resident species, why do you think this happens?
4.
If only one species is considered the "fittest", why do we still have so many variations
among species. Why do some birds have very long pointy beaks, while other birds have
short flat beaks?
5.
How do you think diseases can affect natural selection?
6.
How does this simulation mimic natural selection? In what ways does this simulation fail to
represent the process of natural selection?
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Extension- Changing the Dominance
and Recessive Alleles
Take one of the experiments from the lab. Recreate the
same experiment, EXCEPT when you add the mutation
EDIT THE GENES by switching the dominant and
recessive allele for that trait. Make a hypothesis, fill in
the chart again and compare the results to your initial
experiment.
Experiment
and
Hypothesis
1.
2.
3.
Pheno
type
Selective
Factor
CONTROL
Group
Initial
Population
at F3
CONTROL
Group
Final
Population
Experiment
Group
Initial Population
at F3
Experiment
Group
Final
Population
Conclusion/
Observation
Did switching the alleles for dominant and recessive have any impact on the population of
rabbits? If so Why? In nothing changed Why not?
Two parent rabbits are both heterozygous for the trait. Create Punnet squares for the
original experiment and the new experiment (with the changed alleles). What are the
phenotype ratios of the Punnet squares? Does this evidence support your finding? How?
If this new experiment were to run longer would the end result be the same or different from
the original experiment?
Extension- Working with Pedigrees- Switch from the population chart to the pedigree
chart
Begin by adding a friend and a mutation. Wait until the F5 generation. Copy the Pedigree for two
rabbits (described below) using the key. Assume that male
rabbits are on the left and female rabbits are on the right.
Find these two rabbits, make sure they have at least four
generations:
1. Select a rabbit that has the mutation.
2. Select a rabbit without the mutation but with parents or
grandparent with the mutation.
Answer the following questions:
1. How could using a pedigree be helpful?
2. What does it mean to have a yellow triangle above the rabbit?
3. What does it mean when a rabbit has a red X over it?
4. How accurate are the pedigrees used in this lab? Did each couple only have one baby?
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WHALE ANCESTRY: DNA Activity
As we learn the DNA sequences of more and more organisms, we can compare corresponding sequences
to see which living species have DNA that is most alike. As the DNA for a particular gene is inherited
by new descendent species, and time passes, mutations can occur (replacements of former DNA bases
by different bases), many without any significant effect. The more time that has passed (the more
distant the ancestry), the more mutations will have occurred, and the more differences we will find
You will be provided with eleven DNA segments from the gene for beta-casein, a milk protein found in
all mammals. The segment is 60 base pairs (bp) long, from bp 141 to bp 200 in the gene. That same
corresponding segment is presented for 11 species, including 3 Cetaceans: Right Whale, Sperm Whale,
and a Porpoise; 7 Artiodactyls (a group rather closely related to Cetaceans): a Giraffe, a Hippo, a Cow,
a Camel, a Deer, Domestic Pig, and a Peccary; and one Perissodactyl: the Indian Rhino. The Rhino
serves as a basis for comparison as an “outgroup.”
PROCEDURE:
1. Align the DNA segments from two species, and count the number of loci where the bases differ.
For each pair of species compared, place the number of differences in the proper space on the grid
below.
2. Each team (OF 3-4) should do at least the following (compare with each other):
A. two of the cetaceans (Right Whale, Sperm Whale, or Porpoise)
B. Hippo
C. Giraffe
D. at least two of the Artiodactyls. If there are at least 3 teams in the class, each team
should compare different pairs of Artiodactyls, e.g.: Cow & Giraffe, Camel & Deer, and Pig & Peccary.
E. Rhino
WHALE DNA Discussion
You will find that the numbers sort into two groups: Pairs with 2-4 differences, then pairs with 7-18
differences.
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1. List the pairs of species with only 2-4 differences in their DNA (show number of differences for
each pair)
2. Notice in that set of 9 pairings that there are 4 species that are found in all possible combinations
with each other. What are those species? (Give common names, as used on the strips):
3. What does this suggest about how close those 4 species are related (or how relatively recent they
branched from a common ancestry?
4, Then there are 3 species that are found in their own 3 possible combinations. What are those 3
species?
5. What does this suggest about how close those 3 species are related (or how relatively recent they
branched from a common ancestry?
6. Notice that there is a gap in the number of differences between pairs of DNA segments, showing
none with 5- 7 differences, and only one with 7 differences. What two species show 7 differences?
7. What does that suggest about when those two species branched from each other relative to the
other two groups previously discussed?
8. The remaining pairings all range between 8 and 18 differences in this segment of DNA. What are
the 2 remaining species that were not listed already?
9. It should be obvious, now, what this suggests regarding the relative time when these last 4 species
shared a common ancestor with the first group of 4 species, the second group of 3 species, and the
third group of
2 species. Was this sharing A) more recent than those three groups; B) about the same time as those
three groups; or C) earlier than those three groups?
10. As for our original question, to which species are cetaceans (whales) most closely related?
Comparing the specific numbers of differences between these last 4 species and those previous 7
species can be a little tricky, mainly because differences of 1-3 don’t seem very significant, and the
range is fairly wide (from 8 to 18, with no real gaps in the continuum). However, for our purposes, this
isn’t important.
11. Using the analysis you’ve made above, try drawing a “family tree” with all the species we’ve looked
at here. Show short branches for closely related (recently branching) species, and longer branches for
the more distantly related species. Label the common name for each species at the end of each
branch Most people find it easier to draw the tree as if it’s lying on its side, with the “trunk” end to
the left, and the shorter branches on the right. You might want to practice before drawing it in
neatly below the sample tree.
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On the next page, find the sample tree, using groups of carnivores:
EXTENSION
As you may have guessed, there are sophisticated computer programs, with online access by anyone,
that can not only compare very large DNA segments (even entire genomes) between many different
species, but can also draw branching “family trees” based on those differences, showing which groups
are most closely related (most recently branched from a common ancestor) and those that are more
distantly related (longer branches from common ancestry at an earlier time). Different genes may
give slightly different results, but overall, looking at many genes and many representatives of each
group, a fair amount of consensus has emerged, generally consistent with the small sampling that
you’ve looked at here. In fact. cetaceans and artiodactyls are now tentatively combined in the single
order “Certiodactyla.”
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If you would like to use those online tools to compare and draw trees for whale (or
any particular group of animals), try http://www.grochbiology.org/WhalesActivity.htm and once you
learn how to use the system, you can explore any question on species relatedness using the database at
www.uniprot.org
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