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SOCIAL BEHAVIOR ACTIVITY 3

5. Read “Alarm-Calling Experiment” to learn more about prairie dog
alarm calls.

Alarm-Calling Experiment Percentage of cases in which 50
prairie dogs gave alarm calls 40
Researchers wanted to determine the 30
characteristics of prairie dogs who give 20 Females
alarm calls and those who don’t. The 10
researchers had been studying one
prairie dog town extensively and knew 0
the relationships of nearly all the
individuals residing in it—close kin, Males
like parents, offspring, and siblings, Without close kin
and other more distant familial With close kin
connections. The researchers
performed an experiment where they
dragged a stuffed badger through the
prairie dog town and noted the identity
of callers and non-callers. What they
found is shown in Figure 3.4.
FIGURE 3.4: Alarm calling in male and
female black-tailed prairie dogs

6. Revise or add to your argument in Step 4 for how alarm-calling could
have evolved in the black-tailed prairie dog.

7. Read “Dispersal” to learn more about the praiLraiebAdiodsgSdEiPsUpPerSsGaIlEsvyosltuetmion. 3e

Figure: Evo3e SB 03_03
MyriadPro Reg 9.5/11

Dispersal

Female prairie dogs, as with most mammals, tend to remain in their
birth groups permanently. Males, on the other hand, tend to
disperse from their coteries when they reach maturity and join a
new coterie.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

8. Predict whether males are relatively more likely or less likely to give
alarm calls at these four stages in their lives:

• Living in their birth coterie
• Living in a new coterie but have not yet sired offspring
• Living in a breeding coterie with their offspring
• Evicted from the breeding coterie

Record your predictions in your science notebook, and explain your
reasoning for each prediction.

9. Look at the graph in Figure 3.5 showing the alarm calls given by five
individual male prairie dogs. The researchers followed these
individuals as their living situations changed and kept track of how
often the individual males gave alarm calls. How well do these data
match your predictions in Step 8?

100

Percentage of cases in which 80
prairie dogs gave alarm calls
60

40 Male 1
Male 2
20 Male 3
Male 4
0 Male 5

Living in birth Moved to Living in Eviicted from
coterie with close breeding coterie breeding coterie breeding coterie
but not yet sired
kin with o spring no kin nearby
o spring

Living situation

FIGURE 3.5: Alarm calls by living situation

10. Use what you have learned to refine your argument for how alarm-
calling could be an adaptation that evolved by natural selection in
the black-tailed prairie dog. Be prepared to share your argument
with the class.

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SOCIAL BEHAVIOR ACTIVITY 3

Part B: Meerkats

11. Read the following information about meerkats.

Meerkats

Meerkats can be used as a test case to determine if FIGURE 3.6: Group of meerkats
alarm-calling is always an adaptation to protect
offspring or close kin. Meerkats (Suricata suricatta)
are small predatory mammals that live in cooperative
groups of between 3 and 50 individuals in the desert
in southern Africa. They live in underground
tunnels, which they use for breeding and to escape
predators. Like prairie dogs, meerkats give alarm
calls. But unlike prairie dogs, meerkats who call do
not experience any greater predation risk themselves.
Furthermore, meerkats who do not live with genetic
kin are just as likely to sound an alarm as those who
do live with genetic kin. There are still many
unanswered questions about why meerkats use
alarm calls.

12. Construct an initial argument for why meerkats give alarm calls.
13. Read the additional information in “Meerkat Groups,” and then revise

or add to your argument.

Meerkat Groups

Each meerkat group has a dominant female Probability of dominant1.0
who produces most of the offspring in the female breeding0.9
group in a breeding season. In some cases, 0.8
no other females produce offspring. The 0.7
probability that the dominant female will 0.6
produce offspring depends on group size, as 0.5
shown in Figure 3.7. 0.4
14. Be prepared to discuss the reasoning for 0.3
your arguments about alarm-calling in 0.2
prairies dogs and in meerkats. 0.1

0
< 10 10–14 15–19 20–24

Group size

FIGURE 3.7: Reproduction by group size in meerkats

LabAids SEPUP SGI Evolution 3e D-27
Figure: Evo3e SB 03_06
MyriadPro Reg 9.5/11

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Build Understanding

1. Compare and contrast the arguments for how alarm-calling is an
evolutionary adaptation in both black-tailed prairie dogs and
meerkats. In your response, include the level of certainty that scientists
have about kin selection being an important factor in prairie dog
alarm calls vs. meerkat alarm calls.

2. What are some other social behaviors that might be adaptations that
evolved by natural selection?

3. Issue connection: How do you think human activity may affect the
social behavior of other organisms and thus affect the evolution of
these organisms?
KEY SCIENTIFIC TERMS
adaptation
kin
natural selection
social behavior

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4 Genetic Variation and Change

in the previous activity, you explored how behavioral traits become

more common, or evolve, in a population when the trait increases the chance
that offspring or close kin (with many of the same genes) will survive and
reproduce. Genes bring about traits in organisms and are inherited from one
generation to the next. Small changes or mutations can happen when genes
replicate. Some mutations, like those that influence body size in marine
iguanas, have the potential to lead to evolutionary change in a population. In
this activity, you will investigate the relationship between the genetic disease
cystic fibrosis and the highly infectious disease TB.

FIGURE 4.1: Normal and TB-infected lungs

Guiding Question

What is the role of genetic variation in evolution?

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Materials

FOR EACH PAIR OF STUDENTS

computer with Internet access

Procedure

Part A: Exploring the Link

1. Read “Cystic Fibrosis and Tuberculosis” for some background
information on each disease.

Cystic Fibrosis and Tuberculosis

Cystic fibrosis (CF) is a recessive It is curious that such a
genetic disease that affects about potentially lethal disease has
1 in 2,500 people in the United persisted in human populations
States; about 1 in 20 people are at such a high level. Normally,
carriers of the genetic mutation such mutations fade out of a
that causes this disease. Because population over time, as those
CF is recessive, in order to have with the disease die before they
the disease, offspring must inherit can reproduce. Scientists
two copies of the mutated gene studying CF theorized that
from each parent. Those who carriers may be protected from
inherit only one copy of the other diseases, which could
mutated gene—carriers—do not explain why CF persists.
develop symptoms but can pass
on the gene to their offspring. For As you read in the Unit Issue,
those with CF, a mutation in a TB is a disease caused by the
channel protein prevents the bacterium Mycobacterium
normal flow of salts out of cells of tuberculosis and mainly affects
the gut and lungs. This leads to the lungs. Between 1600 and
the formation of thick mucus that 1900 in Europe, the TB pandemic
can obstruct the intestine and caused 20% of all deaths. Because
block breathing in the lungs. both TB and CF affect the lungs,
scientists suspected a connection
Historically, without treatment, between the two diseases. They
CF patients died before they have hypothesized that having
reached childbearing age. one copy of the CF mutation and
Today—with modern one normal gene provides
medications, therapies, and protection against certain
surgeries—patients can live diseases, including TB.
beyond 40 years old.

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GENETIC VARIATION AND CHANGE ACTIVITY 4

2. With a partner, discuss the following questions:

• What is the difference between a genetic disease and an infectious

disease?

• How do you think a genetic disease could provide protection against

an infectious disease?

• If there were a continuous high chance of contracting TB among a

population, would you expect the number of CF cases to increase,
decrease, or remain the same over several generations? Explain your
thinking.

• How might people's access to health care affect the scenario in the

previous question?

3. Follow your teacher’s instructions to share your thinking with the class.

Part B: Simulating the Hypothesis

4. Prepare for the simulation by reading “The Cystic Fibrosis and
Tuberculosis Simulation.”

The Cystic Fibrosis and Tuberculosis Simulation

You will use a simulation to the 1950s, only routine comfort
analyze data about the care was available. Between 1950
relationship between CF and TB and 1990, medications became
among adults in a population. available to treat patients’
This simulation is based on real- symptoms, and after 1990 some
world data in Europe, where the patients had access to surgeries
CF mutation is thought to have (such as lung transplants),
originated. The simulation allows enzyme therapies, and
you to choose the probability of specialized antibiotics.
getting TB (0%, 40%, or 80%)
and to vary the average health- The simulation also allows you
care level for people with CF, to analyze the data by wealth
based on the era (pre-1950, distribution. Specifically, you will
1950–1990, and post-1990). Each be able to determine the relative
era provided unique health-care rates of genotypes among adults
options to CF patients. Prior to for the top 20th and the bottom
20th percentile in wealth.

5. With your partner, visit the SEPUP SGI Third Edition page of the
SEPUP website at www.sepuplhs.org/high/sgi-third-edition. Follow
your teacher’s instructions to access the simulation.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

6. Decide with your partner how you would like to set the variables of the
simulation. You can choose the likelihood of getting TB in your
population and the average health-care level by era.

7. Press “Run Simulation.” The line graph shows the percentage of each
trait in the population for each generation over time.

8. Record your results and any additional data or observations in your
science notebook. Be sure to note any questions you have that you
would like to test.

9. Below the first graph, set the variables again to repeat the simulation.
Keep one variable the same, and change the other. For example, if you
initially set the TB rate to 80%, keep this variable at 80% and choose
another health-care variable.

10. Look over the second line graph, and compare it to your initial line
graph. Record the new data and any differences you observed in your
science notebook.

11. Above the second line graph, press “See Differential Outcomes Based
on Wealth Disparity.” Two line graphs show the percentage of each
trait in the population for each generation over time among the top
20th and the bottom 20th percentile in wealth.

12. Record your results in your science notebook. Be sure to note any
questions you have that you would like to test.

13. Continue to run the simulation and change the variables.
Hint: Keep changing just one variable at a time until you can explain

the relationship between CF and TB. Be sure to record your variables
and results for each test that you run.

Build Understanding

1. What is the evidence for a cause-and-effect relationship between the
probability of contracting TB and the frequency of the CF mutation?

2. CF is caused by a single mutation. Explain how the environment affects
whether this mutation is beneficial, harmful, or neutral for a person.

3. Explain how environmental changes affect the CF trait over time in
your population. Use evidence, including mathematical
representations, from your investigation to support your explanation.

4. Issue connection: How might people be changing the environment,
and therefore how are they affected by evolution?

D-32

GENETIC VARIATION AND CHANGE ACTIVITY 4

KEY SCIENTIFIC TERMS

carrier
evolution
gene
genetic variation
mutation

Extension: Engineering Connections

Scientists are using genetic engineering to treat genetic diseases, like CF
and sickle cell anemia. A gene-editing technique called CRISPR has
already been used to correct the CF mutation in human stem cells, and
the same technique is currently being used in humans to reverse the
symptoms of sickle cell anemia. To learn more about these very recent
efforts, visit the SEPUP SGI Third Edition page of the SEPUP website at
www.sepuplhs.org/high/sgi-third-edition.

FIGURE 4.2: Normal red blood cell (left) and a sickle cell (right)

D-33



5 Is It Evolution?

populations change over time due to changing environments.
Changes to the environment can occur as a result of naturally occurring
events (such as severe weather events and earthquakes) or can be human-
induced (for example, pollution and habitat modification). These
changes may result in evolutionary changes to a population, or they FIGURE 5.1: Biston betularia,
peppered moth, in its light
and dark forms
could be limited to ecological changes that do
not favor certain genotypes and are therefore
not passed from one generation to the next. For
example, peppered moths are typically light-
colored (Figure 5.1, top image), but after the
industrial revolution, when air pollution
increased and left black soot on tree trunks,
more dark-colored moths were observed
(Figure 5.1, bottom image).

Look over the graph in Figure 5.2. What do you
notice about the data? What do you think
happened to the light-colored moths? Is this an
evolutionary change, or is it ecological?

Percentage of moths captured 100 Light colored
90 Dark colored
80
70 1850 1900 1950
60
50
40
30
20
10
0
1800

Year

FIGURE 5.2: Peppered moth coloration over time

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Guiding Question

What is required for evolution by natural selection to occur?

Materials

FOR EACH GROUP OF FOUR STUDENTS

set of 8 Is It Evolution? cards

FOR EACH STUDENT

Student Sheet 5.1, “Is It Evolution?”

Procedure

1. In your science notebook, describe what is required for evolution by
natural selection to occur. Refer to the previous examples in this unit to
help you, as needed. Be prepared to discuss your ideas with the class.

2. Look over the set of Is It Evolution? cards provided by your teacher.
The scenarios on these cards describe examples or non-examples of
evolution by natural selection.

3. Follow your teacher’s instructions to analyze the cards with your
group. Record your initial ideas on Student Sheet 5.1, “Is It Evolution?”

4. Once your teacher has assigned your group a card to focus on, work
with your group to construct an explanation about why your card does
or does not describe an example of evolution by natural selection.

5. Record your group’s explanation on Student Sheet 5.1.
6. Follow your teacher’s instructions to share your group’s explanation

with the class.

D-36

IS IT EVOLUTION? ACTIVITY 5

Build Understanding

1. Choose one of the populations from the cards in this activity—either
the population that your group focused on or another one. Construct
an explanation for why your chosen population is or is not an example
of evolution by natural selection. In your explanation, be sure to
address all the requirements for evolution to occur.

2. Issue connection: Antibiotics are drugs used to kill disease-causing
bacteria. Antibiotic-resistant bacteria develop when a naturally
occurring mutation in the bacteria’s genes provides protection against
the antibiotic. The antibiotic-resistant bacteria multiply in the organism’s
body and can even transfer resistance genes to other bacteria.

The graph in Figure 5.3 provides data on the number of people with
bacterial infections that are resistant to Carbapenem—a widely used and
reliable antibiotic for a variety of infections. Examine the graph, and
answer the questions that follow.

Number of anti-biotic resistant cases (thousands) 10 FIGURE 5.3: Number of antibiotic-
resistance cases over time
Worldwide
8 U.S.

6

4

2

0 2014 2015 2016 2017 2018

Year

a. What do you notice about the data?
b. As bacteria gain resistance to Carbapenem, what could this mean

in terms of bacterial evolution?
c. If antibiotic resistance continues to increase, what do you think

will happen?
d. WimFLiaghpbuaAartceidat:ssErevSooEtfP3hrUeeisPSpiBnSoG0gs5IsaE_invb0o3tlielbuetiionotvniic3roerensmisteanntcael,?economic, and social
e. HMoywriaidsPtrhoiRseagn9e.5x/a1m1 ple of humans affecting the evolution of other

species?

D-37

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

KEY SCIENTIFIC TERMS

ecological
evolution
natural selection

D-38

6 Increasing Timescales

so far, you have focused primarily on evolution that happens

within a population of organisms over just a few generations or a relatively
short period of time. In this activity, you will explore what happens when
these changes keep occurring for many more generations and much longer
periods of time.

Guiding Question

What happens when evolution occurs over longer periods
of time?

FIGURE 6.1: Anole lizard species show
diversity in limb length, tail length, and
the color of their dewlaps (the loose skin
hanging below their necks).

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Materials

FOR EACH STUDENT

Student Sheet 6.1, “Speciation in Anoles”

Procedure

Part A: Speciation in Action

1. Look back at the investigative phenomenon at the start of Activity 1:
Changing Environments. Work with your partner to construct an
explanation for the color variability among members of this single
species, using what you know about evolution by natural selection.
Be prepared to share your explanation with the class.

2. Read the following text, “The Biological Species Concept.”

The Biological Species Concept

The biological species concept is the most The biological species concept is
widely accepted definition of a species in straightforward, but it turns out that there are
terms of interbreeding. According to the a number of areas where it is not helpful. For
biological species concept, a biological example, many species, such as bacterial
species comprises all the populations of species, do not reproduce sexually. Many
individuals who can actually or potentially plant species crossbreed under natural or
breed with one another in nature to produce artificial conditions. Also, the concept cannot
fertile offspring. The result of this be applied to fossil organisms because their
interbreeding is the movement of genes, breeding cannot be observed. Nevertheless,
called gene flow, throughout the species. the biological species concept gives scientists
Members of the same species share a a snapshot of the evolution of new species in
common group of genes—a gene pool—and many groups of plants and animals.
a common evolutionary history. Should
members of different populations mate but Populations who share a common gene pool
produce no fertile offspring or no offspring at are thought to be in the early stages of
all, or very rarely breed with one another even separation from one another. This is likely to be
when present in the same location, they are the case if individuals in the two populations
considered different biological species. meet the following two conditions:
Speciation is the formation of species as a
result of barriers to gene flow that split the • They usually breed together if they meet
gene pool, followed by an accumulation of
differences between the gene pools. in the wild.

• Their breeding produces offspring who are

fertile (able to produce their own offspring).

D-40

INCREASING TIMESCALES ACTIVITY 6

3. Watch the video on evolution in action for this salamander species.
4. Compare your explanation for the color variability among salamanders

in Step 1 with the one given in the video. Be prepared to discuss your
explanation with the class.

Part B: Speciation in Anoles

FIGURE 6.2: Salamander coloration differs by geographic region and has evolved for
protection from predation and for reproduction.

5. Read the claims on Student Sheet 6.1, “Speciation in Anoles.” This will
give you an idea of what to listen and watch for as you view the video.

6. Complete Student Sheet 6.1 as you watch the video on anoles.
7. Share and discuss your responses with your group. Come to an

agreement on your responses to each claim. Be prepared to share your
responses with the class.

Build Understanding

1. Explain how the salamanders are an example of “speciation in action.”
2. Explain how natural selection has led to adaptation and speciation in

anoles. Include as much evidence from the second video as possible, as
well as what you learned about the requirements for evolution to occur
in Activity 5: Is It Evolution?
3. Issue connection: How do you think human activity may affect the
process of speciation?

D-41

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

KEY SCIENTIFIC TERMS

biological species
biological species concept
gene
gene flow
gene pool
speciation

Extension 1

Scientists have used specific pieces of evidence to construct the
phylogenetic tree for anoles throughout the Caribbean. Visit the SEPUP
SGI Third Edition page of the SEPUP website at www.sepuplhs.org/​
high/sgi-third-edition to watch more of the video presented in this
activity and then read about the genetic variation of anoles.

Extension 2

Several anole species may still be evolving. One example is the bark anole that
is native to the northern Caribbean islands and was introduced into Florida.
Each group of anoles is the same species, but they have developed different
signaling traits over time. What happens when anoles of the same species, but
from different locations, come together? Visit the SEPUP SGI Third Edition
page of the SEPUP website at www.sepuplhs.org/high/sgi-third-edition to
read about the future of genetic variation among anole species.

D-42

7 Extinction

Investigative Phenomenon

Life on Earth is not constant. It is always changing—sometimes over short time spans,
and sometimes over long time spans. Look at the following graph. What patterns do
you notice? What questions do you have?

20

Extinction rate 15
(families per million years)
10

5 100 0

0
600 500 400 300 200

Millions of years ago

FIGURE 7.1: Extinction rate over time, from 600 million years ago to the near
present. The lower shaded area represents the background (average) rate of
extinction.
LabAids SEPUP SGI Evolution 3e
Figure: Evo3e SB 07_01
MyriadPro Reg 9.5/11

FIGURE 7.2: Fossil of a vertebrate
species that is now extinct

D-43

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

So far in this unit, you have focused primarily on evolutionary changes in
current populations and on recent cases of speciation. But if you were to travel
back 4 billion years, life on Earth existed only as single-celled organisms in the
ocean. And it remained this way for the next 2 billion years, until the first
multicellular organism evolved. It took another 1½ billion years or so for the
first plants and animals to evolve. Once this happened, though, the rate at
which new life-forms evolved increased dramatically. Nonetheless, 99% of all
the species that have ever existed on Earth have gone extinct. In this activity,
you will explore evolutionary patterns among life-forms over time and
consider why some life-forms have persisted and others have gone extinct.

Guiding Question

What factors cause species to go extinct?

Materials

FOR EACH PAIR OF STUDENTS

Student Sheet 7.1, "Time Period Labels"
set of Life-Forms cards
set of The Five Mass Extinction Events cards
scissors

Procedure

1. With your partner, obtain a set of Life-Forms cards. Read through each
card, noting both the images and the data tables.

2. Place the cards in what you both believe to be chronological order,
from oldest (the first to evolve) to most recent (the last to evolve).

3. Compare your ordering with at least one other pair’s ordering. Make
any desired changes to your own ordering, based on your comparison.

4. With your partner, obtain Student Sheet 7.1, "Time Period Labels," and
cut the labels apart. Place a label above each Life-Form card. Your
oldest Life-Form card will have the Time Period label “541 mya–485
mya” (mya = million years ago) above it, and your most recent Life-
Form card will have the Time Period label “2.6 mya–present” above it.

5. Listen as your teacher shares the ordering of time periods that was
established and is accepted by scientific experts. Use this established
ordering to make any needed adjustments to your own ordering.

D-44

EXTINCTION ACTIVITY 7

6. In your science notebook:

• Describe any patterns you notice in the life-forms, going from the

oldest to the most recent.

• Describe any patterns you notice in atmospheric oxygen and carbon

dioxide levels and temperature across the time periods.
7. With your partner, obtain a set of The Five Mass Extinction Events

cards. A mass extinction event is a widespread and rapid decrease in
the biodiversity on Earth. These events occur when a large number
of species die out in a relatively short period of time. Read the
information on the cards and decide together where to place the
cards on your timeline. In your science notebook, describe how you
and your partner made these decisions.
8. Listen as your teacher shares the timing of these five mass extinction
events that was established and is accepted by scientific experts. Use
this to make any needed adjustments to your placement of these
events on your timeline.

Build Understanding

1. What kinds of evidence about evolution did you use to order the cards?
How confident were you about this evidence?

2. What patterns in the evolution of life-forms are evident from the
images? What factors might explain the change in life-forms over time?

3. How does the magnitude of each of the five extinction events compare
to the background rate of extinction?

4. Explain the factors that caused the extinction of species and entire life-
forms in the past. How confident are you about these explanations?

5. Issue connection: Revisit the investigative phenomenon at the start of
this activity. Provide an initial explanation for the patterns shown in
the graph. Be sure to address both speciation and extinction in your
explanation.

KEY SCIENTIFIC TERMS

extinction
mass extinction event

D-45



8 The Anthropocene

as you saw in the last activity, extinction is a natural phenomenon that
has occurred continuously since life evolved. You also learned that there
have been five mass extinction events in the history of life on Earth. Many
scientists argue that we are in the middle of a new era in time—the
Anthropocene—in which the earth will experience the sixth mass
extinction event. The Anthropocene is a human-dominated geological
period of time, beginning when humans started having a major impact on
the earth. In this activity, you will examine the evidence for a sixth mass
extinction event and either support or refute this argument.

b
a

c
d

FIGURE 8.1: Human activities—such as (a) open-pit mining of minerals,
(b) clear-cutting forest for agriculture, (c) urban expansion, (d) releasing
invasive species (such as the Burmese python in the Florida Everglades),
and (e) building oil rigs in the ocean—have significantly impacted the
e survival of native species.

D-47

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Guiding Question

What is the role of human activity in the extinction process?

Materials

FOR EACH STUDENT

Student Sheet 8.1, “Five Extinct Species”
Computer with Internet access

Procedure

1. Read about five extinct species or groups of species. As you read, record
the following information on Student Sheet 8.1, “Five Extinct Species”:

• When the species went extinct
• The factor or factors that caused the species to go extinct

Woolly Mammoth

Mammoths evolved 3 to 4 million years ago. More recent evidence suggests that the
They thrived and spread to North America reduced population size, which led to
about 1.8 million years ago. But about 10,000 inbreeding, may have also been a factor.
years ago, all but a few small herds of Inbreeding causes the accumulation of an
mammoths had died, and the last mammoth excessive number of harmful genetic
died around 4,000 years ago. mutations. Researchers compared the DNA of
mammoths from 45,000 years ago to that of
There is no evidence that an asteroid or the last remaining mammoths and discovered
other catastrophic event brought about the that the latter had a “genomic meltdown.” The
extinction of the mammoths. So, what large number of mutations had caused the
happened 10,000 years ago that caused this mammoths to lose their sense of smell and
huge drop in the mammoth population? also led to reduced male fertility.
FIGURE 8.2: Woolly mammoth
One possibility is that the mammoths could
not survive the drastic changes in climate and
vegetation that occurred when the last ice age
ended. In addition, humans—who lived at the
same time as the mammoths—were moving
into new environments as their population
grew. The end of the last ice age helped
expand humans’ geographic range into areas
where mammoths lived. Increased hunting of
mammoths by humans may have contributed
to the population’s extinction.

D-48

THE ANTHROPOCENE ACTIVITY 8

Dodo Bird

The small indian ocean island of FIGURE 8.3: Dodo bird
Mauritius was once home to the In addition, the dodo
large, flightless dodo bird, which
had evolved over several million population was relatively small,
years on the island. Mauritius is and thus the genetic diversity
isolated, and because the dodos was relatively low. When genetic
had little competition from diversity is low, there is also a
other organisms, they freely fed low probability that any
on fruit that had fallen to the individual in the population will
ground. These dodos were able have the traits required for
to store large amounts of fat in survival and reproduction if the
times when food was scarce, environment changes. Eighty
enabling them to survive and years after humans arrived,
reproduce. Eventually, over dodos became extinct.
generations, the dodos increased
in size.

Their flightlessness was a trait
that also evolved over time. As
plant eaters in an environment
with no predators, the inability
to fly had no effect on the
dodo’s ability to survive.

In the 16th and 17th centuries,
Portuguese and Dutch explorers
sailed to the Mauritius Island. The
flightless dodos could not flee
from humans, who hunted them
for food and for their eggs. The
sailors also brought with them
pigs, monkeys, and rats that fed
on the dodos’ eggs and chicks and
perhaps even adult dodos. On a
small island, the dodo population
could not survive under these
changed conditions.

D-49

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Cichlids

Bordering kenya, uganda, and cichlids were also fished along
Tanzania, Lake Victoria is the with the perch, introducing the
second largest freshwater lake in perch appears to be the reason
the world. Within its depths, over for the extinction of as many as
the last 200,000 years more than 200 species of cichlids and the
300 species of cichlid fish evolved decline of other fish, such as
to live in the various habitats catfish and lungfish.
within the lake. Some cichlids,
such as tilapia, are edible, and The loss of the cichlid species
some larger species are popular that ate algae allowed the
sport-fishing prey. Genetic amount of algae in the lake to
evidence suggests that cichlids rise. Because algae consume
evolved from a common ancestor. oxygen, their abundance made it
difficult for other small plants
In the 1950s, the British and animals to get enough
government introduced the oxygen for themselves, further
large Nile perch into the lake, threatening the lake’s
with the idea that the perch biodiversity. The Lake Victoria
would provide the local people ecosystem is adjusting to these
with a new protein source and a changes but will not likely reach
new commercial fishery. the level of biodiversity that
Unfortunately, the perch ate the existed before the introduction
cichlids and other fish. Because of Nile perch.

FIGURE 8.4: Cichlid
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THE ANTHROPOCENE ACTIVITY 8

Passenger Pigeon

Passenger pigeons were once individual, a bird named Martha,
considered to be the most died in her cage at the Cincinnati
abundant bird species in the Zoo. How could a species go
United States, if not the world. from billions to none in such a
An ornithologist in the 1800s short period of time?
estimated that one flock he
witnessed had 2 billion birds. Because this species nested in
Passenger pigeons inhabited the such large, accessible colonies, it
deciduous forest in the eastern was a reliable source of food for
part of the country, nesting in Native Americans and early
colonies that could be several settlers. People could easily find
miles wide and 40 miles long. nests and harvest the chicks. As
But in 1914, the last surviving the human population grew and
FIGURE 8.5: Passenger pigeon became more urbanized, a

commercial market for
pigeon meat developed and
prospered. The development
of railroads allowed pigeons
to be shipped all along the
East Coast.

This massive harvesting of
chicks was so disruptive that
entire colonies disappeared
at an alarming rate. The last
remaining wild population
was eliminated in the state of
Michigan in 1889. Small
flocks of passenger pigeons
were kept in captivity, but
they were not able to be
maintained. When Martha
died in 1914, the species was
officially declared extinct.
Martha’s body was carefully
preserved and is now on
display at the U.S. National
Museum of Natural History
in Washington, D.C.

D-51

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Mount Glorious Torrent Frog

Amphibians are very vulnerable probably played a key role. Forests
to extinction, and scientists were cut down for commercial
estimate that one out of every logging, which caused soil runoff
three species are endangered. into the streams. This made the
One species, the Mount Glorious stream habitat unsuitable for the
torrent frog, was officially frogs to nest and reproduce. Some
declared extinct in 2004. This conservation biologists suspect
small frog was native to that infectious fungal disease may
Australia, living in rainforest also have played a role. The
streams in three mountain ranges fungus infects the thin, moist skin
on the eastern coast. This species that frogs use to absorb water and
was considered common in the to balance the levels of minerals
1970s and was fairly easy to spot they need to support heart
in leaf litter along the stream— function. An infected frog, unable
but within just a few years, the to maintain a steady heartbeat,
Mount Glorious torrent frog will die of a heart attack. The
population began to decrease. fungus then releases spores into
the water to infect the next frog.
What led to this rapid decline This deadly cycle is responsible
and extinction? There are likely for the decline of more than 500
several factors, but habitat amphibian species.
destruction due to deforestation

FIGURE 8.6: Mount Glorious torrent frog
D-52

THE ANTHROPOCENE ACTIVITY 8

2. Analyze the graph in Figure 8.7. In your science notebook, describeCumulative percentage of extinctions
what the data in this graph shows.

2.50

2.00 Mammals
Birds

1.50 Other vertebrates

1.00

0.50

0.00
1500–1600 1600–1700 1700–1800 1800–1900 1900–2010
Time period

FIGURE 8.7: A group of scientists examined the number of vertebrate species that have gone
extinct since the year 1500. They calculated that the observed extinctions in just the past 114
years would have taken approximately 5,000 years at the background rate of extinction.

LabAids SEPUP SGI Evolution 3e
FM i3gyur. iraAewd:nPhEravaooltyR3tzeehegeStB9dh.05ae8/t1g_a1r1ia1npthhiins
Figure 8.8. In your science notebook, describe
graph shows.

Average of the past Projected extinctions
ve mass extinctions Known extinctions

Crabs, etc.
Sharks, etc.

Conifers
Cycads
Clams, etc.
Snails, etc.
Ray- nned shes
Amphibians
Reptiles

Birds
Mammals

0 10 20 30 40 50 60 70 80 90 100
Percentage of Species

FIGURE 8.8: The criterion for a mass extinction is that 75% of species must have gone extinct; this D-53
benchmark is shown by the black vertical line at the 75% mark. The dark-blue bars represent the
percentage of species that are “extinct” or “extinct in the wild” for each group. The light-blue bars
show the percentage of species that are threatened with extinction for each group.

LabAids SEPUP SGI Evolution 3e
Figure: Evo3e SB 08_12
MyriadPro Reg 9.5/11

c7 m0 y0 k9 c0 m42 y92 k0 c100 m0 y20 k70 c25 m0 y15 k90

Maps1 Maps2 Maps3 Maps4 Maps5

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

4. Obtain information about the Anthropocene and a possible sixth mass
extinction from one or more additional sources, as instructed by your
teacher. The sixth mass extinction is the potential next mass
extinction event in which over 75% of all species go extinct.

Build Understanding

1. Summarize how humans change the environment in ways that may
cause other species to become threatened, endangered, and eventually
go extinct. Use examples from throughout the course in your
summary.

2. Do you think that human activity might also be affecting the rate of
speciation—causing either an increase or a decrease in different types
of organisms? Explain your thinking.

3. Issue connection: Use the information you gathered throughout this
activity to either support or rebut the following claim: The earth will
experience a sixth mass extinction due to human activity. Be sure to
address evidence about both extinction and speciation in your
response.
KEY SCIENTIFIC TERMS
Anthropocene
sixth mass extinction

Extension

Habitat destruction, particularly deforestation, is a major driver for
extinction. Species that depend on forests are particularly vulnerable as
humans expand their activities into wildlife habitats. What evidence do
scientists have for tracking the survival or extinction of species? Visit the
SEPUP Third Edition page of the SEPUP website at www.sepuplhs.org/
high/sgi-third-edition to read an article about four species that went
extinct due to forest loss.

D-54

9 Evidence and the Theory of Evolution

the theory of evolution is a scientific theory that is based on many
lines of evidence. This theory has developed over time, from Charles
Darwin’s observations in the Galápagos Islands beginning in 1831 to
modern-day observations of many different types of organisms. So far, you
have explored how both careful observations and experiments in nature
and examination of the fossil record provide evidence to support the
theory of evolution. In this activity, you will gather information about
some additional types of evidence that scientists use to support evolution
as a unifying theory in the life sciences.

Guiding Question

What other kinds of evidence support the theory of
evolution?

FIGURE 9.1: Charles Darwin and his wife, Emma, who was influential in developing his theory of
evolution.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Procedure

1. Complete the following readings, which describe different types of
evidence to support the theory of evolution.

2. Follow your teacher’s instructions for how to use the Stop to Think
questions as you read.

Reading Early stage Gill slits
Middle stage Forelimb
Embryology Tail
Late stage
Embryos are organisms in the early Forelimb
stages of development before they are Tail
born or hatched. Embryology is the
study of those embryos and how they Forelimb
develop until they become fully formed Tail
organisms. Many species share common
features when they are embryos.
Darwin suggested that these shared
features could indicate that the species
are related. Essentially, the stages and
forms present during embryonic
development can point to a shared
common ancestor.
Look at Figure 9.2, which shows a bat
embryo in three different stages of
development: early, middle, and late. In
its earliest stage, the bat has gill slits. But
because bats are mammals, when they
are fully formed organisms they breathe
through their lungs, not gills. Gill slits
are present in bats only when they are
embryos; this trait is lost by the time the
bats are fully formed.

FIGURE 9.2: Bat embryo at three different stages
of development
D-56

EVIDENCE AND THE THEORY OF EVOLUTION ACTIVITY 9

Figure 9.3 shows three different stages of development for embryos of five
different species: bat, chicken, salmon, human, and snake.

EaEralrylyssttaaggee

MiddMlieddsletastgagee

LaLattee ssttaagge e

BBaatt CChhicikceknen SaSlamlmoonn HHuummaann SSnnakaeke
FIGURE 9.3: Three different stages of development for five different species: bat,
chicken, salmon, human, and snake

LabAids SEPUP SGI Evolution 3e

STOP TO THINK 1Figure: Evo3e SB 09_03
MyriadPro Reg 9.5/11

a. What do you notice when you compare a species’ different stages of

development?c7m0y0k9
c0 m42 y92 k0 c100 m0 y20 k70 c25 m0 y15 k90

Maps1 Maps2 Maps3 Maps4 Maps5

c0 m30 y70 k0 c0 m43 y94 k0 c15 m10 y0 k85 c95 m50 y30 ko c15 m90 y90 k0

c60 m30 y100 k0 c50 m20 y75 k0 c15 m90 y90 k0 c90 m55 y40 k0 c39 m7 y12 k0

b. What do you notice when you compare different species at the same
c15 m10 y0 k85 c80 m0 y0 k55 c12 m7 y0 k0 c0 m0 y0 k6 c25 m0 y15 k90

stage of development?

c. Based on these comparisons, what conclusions can you draw about
how closely related these five species are?

Comparative Anatomy

Comparative anatomy is the study of similarities and differences in
anatomy among species, typically beyond embryonic form. Scientists use
these comparisons to determine how and if species are related to one
another and how a species may have evolved. For example, the
evolutionary origin of birds was historically debated. Some groups of
scientists believed that birds evolved from dinosaurs, while other groups
argued that birds evolved from other reptiles—such as crocodiles.

D-57

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Shortly after Charles Darwin published his
groundbreaking brook On the Origin of
Species, a fossilized feather was found in 1860
in Germany dating to the late Jurassic period—
approximately 150 million years ago. Just two
years later, a nearly complete Archaeopteryx
skeleton was discovered and classified as a
bird, despite having characteristics of a
reptile—such as clawed forelimbs and a long,
bony tail. Scientists made detailed
comparisons of the anatomy of birds and
reptiles and found that Archaeopteryx was
most similar to a particular group of dinosaurs
(therapods)—making it a transitional fossil
between birds and reptiles. By the 1870s, the
iconic “Berlin specimen” of Archaeopteryx was
discovered, showing reptilian-like teeth. With
this discovery, scientists formally proposed the
evolutionary relationship between birds and
theropod dinosaurs.

FIGURE 9.4: The Berlin specimen (Archaeopteryx).

sharp long forelimbs
teeth with wing-like
proportion no teeth

short large
forelimbs breastbone

reversed
first toes

Compsognathus (theropod) Archaeopteryx Gallus (chicken)

FIGURE 9.5: Comparative analysis of theropod dinosaur, Archaeopteryx and chicken skeletons

D-58

EVIDENCE AND THE THEORY OF EVOLUTION ACTIVITY 9

STOP TO THINK 2

Most paleontologists today consider birds to be living dinosaurs. What
evidence do you think they might be using to draw this conclusion?

Genetics

As you have seen, scientists use evidence such as similarities in skeletal
structures and other physical traits to investigate evolutionary
relationships. Thanks to advances in genetics and biotechnology,
scientists studying evolution can now use the genetic material itself. Each
cell in an organism contains the genetic information needed to perform
all its functions, such as obtaining energy, moving, and getting rid of
wastes. Genetic information is located in DNA in the chromosomes
found in every cell. DNA is made up of four chemicals (whose names are
abbreviated as A, T, G, and C) that are shared among all living organisms,
from bacteria to humans. These chemicals are strung together, like beads
on a string, to generate a code that is read by the cell’s machinery and
translated into proteins. When it comes to comparing DNA among
species, the more similar the DNA, the more recently the species shared a
common ancestor.

FIGURE 9.6: Structure of DNA D-59
SEPUP SGI Genetics SB
e: 3422GenSB 10_01

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Hominoids

lemurs New World monkeys orangutans gibbons gorillas Hominids chimps
monkeys humans ~5 mya

> 20 mya

35 mya

FIGURE 9.7: Basic evolutionary tree for the hypothesis of relatedness among primates

LabAids SEPUP SGI Evolution 3e
Figure: Evo3e SB 09_07

MToyrmiadaPkreo tRheegi9r.c5o/1m1 parisons, scientists often look for stretches of related
genes among different species. Having homologous genes (genes that can
be traced from two separate creatures to a single common ancestor)
implies that two species have the same gene because they inherited them
from a common ancestor. For example, humans and chimpanzees share
about 99% of their genes and likely split from their common ancestor a few
million years ago. However, looking at specific genes can help to determine
the interrelatedness of species. For example, humans and chimpanzees are
98% homologous for the insulin gene, whereas humans and chicks are only
64% homologous for the same gene; this means that humans and
chimpanzees are more closely related than humans and chickens. Using
homologous gene comparisons, scientists can create evolutionary trees of
how different species are related to one another.
Genetic evidence that supports the theory of evolution is growing quickly.
As genetic technologies are relatively new, molecular evidence often adds
to paleontological evidence and sometimes rewrites what we once thought
to be fact. For example, it was long hypothesized that whales descended
from land mammals that had returned to the ocean. Based on the fossil
record and comparative anatomy, it was assumed that whales were most
closely related to some hoofed mammals, such as cows and sheep.
However, genetic comparisons of proteins in the whales’ milk demonstrated
greater similarity with the hippopotamus. As scientists study more and
more organisms on a genetic level, we may gain greater clarity about how
particular species evolved.

D-60 c7 m0 y0 k9 c0 m42 y92 k0 c100 m0 y20 k70 c25 m0 y15 k90 Projected extinctions
Known extinctions
Maps1 Maps2 Maps3 Maps4 Maps5

c0 m30 y70 k0 c0 m43 y94 k0 c15 m10 y0 k85 c95 m50 y30 ko c15 m90 y90 k0

c60 m30 y100 k0 c50 m20 y75 k0 c15 m90 y90 k0 c90 m55 y40 k0 c39 m7 y12 k0

EVIDENCE AND THE THEORY OF EVOLUTION ACTIVITY 9

STOP TO THINK 3

a. How has technology increased our ability to determine evolutionary
relationships?

b. If evidence from genetics contradicts evidence from other methods,
do you think the evidence from genetics should be weighted more
heavily?

Build Understanding

1. Why do you think evolution is referred to as a theory?
2. Choose two types of evidence from the reading or from elsewhere in

this unit, and create an infographic explaining how these types of
evidence support the theory of evolution. Include both text and
graphics in your response.
Note: An infographic uses engaging visuals (text, images, charts,
and/or diagrams) to quickly and clearly present information or data.
3. Issue connection: What kind of evidence do you think was used to
generate the graph in Figure 7.1 at the start of Activity 7: Extinction?

KEY SCIENTIFIC TERMS

comparative anatomy
DNA
embryology
embryos
evolution
fossil record
genes
homologous genes
scientific theory
theory of evolution

Extension

To learn more about how scientists study and collect evidence for
evolution, visit the SEPUP SGI Third Edition page of the SEPUP website
at www.sepuplhs.org/high/sgi-third-edition.

D-61



10 Applying Evolutionary Thinking

conservationists are people who advocate or work for the
protection of the environment. Knowledge of the evolutionary history and
relationships of groups of species helps scientists and conservationists
understand the biodiversity of an area. Such information can also help
conservationists decide where and how to focus their efforts. One approach
to conservation is to protect the greatest amount of biodiversity, including
both species and genetic diversity.
As you learned in the previous activity, to understand the relationships
between species or groups of species, scientists have devised various
classification systems. Some systems compare the observable characteristics
of organisms—such as their physical structures, embryological development,
and genetic similarities—and then assign the organism to a place on an
evolutionary tree.
In this activity, you will learn about conservation efforts on the fictional
island of Kapikua. You will apply everything you’ve learned so far about
evidence for evolution as you decide which area of the island you think
should be conserved.

FIGURE 10.1: Conservationists in Indonesia working with orangutans

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Guiding Question

How do scientists use evidence of evolution to make
decisions about conservation?

Procedure

Part A: Conservation of Primates on Kapikua

1. Read “Conservation on Kapikua.” With your partner, discuss your
initial ideas about what should happen on the island.

Conservation on Kapikua

On the island of Kapikua, the to fully support conservation at
government plans to expand its only one of four forest areas being
biodiversity conservation efforts. considered. You are a member of
The government has two goals: (1) the conservation team who will
Protect the primate species that advise on which area should get
live in the forests on the island and full conservation support.
nowhere else, and (2) promote
sustainable practices that protect
the overall biodiversity of the
island ecosystem. FIGURE 10.2: The island of Kapikua

The endangered
primates are unique
and are very
sensitive to habitat
changes, which
puts them at a B
higher risk of coral reef lowland D
extinction. The tropical tropical
primates have also A rainforest montane
become a well- mangrove cloud forest
known attraction north
for ecotourists from forest
around the world. C KAPIKUA
The government lowland ISLAND
tropical
rainforest
south

has enough funds

South Sea

D-64
LabAids SEPUP SGI Evolution 3e
Figure: Evo3e SB 10_02

APPLYING EVOLUTIONARY THINKING ACTIVITY 10

Conservation on Kapikua continued

Five species of primates live of teeth (whether for grinding,
across Kapikua. Primatologists— crushing, or tearing) can be
scientists who study primates— compared to determine how
recently conducted a study of the each species is related.
five species, using a comparative
anatomy analysis of the primates’ The primatologists presented
teeth to determine how they are the following results from their
related to one another. The type analysis to your team of
conservationists.

SPECIES ISLAND AREA(S) TYPE OF TEETH
Primate 1 Lowland tropical rainforest Crushing and grinding
Primate 2 north
Primate 3 Lowland tropical rainforest Crushing, grinding, and
south tearing
Primate 4 Tropical montane cloud Crushing and grinding
forest, lowland tropical
rainforest north Crushing, grinding, and
Mangrove forest tearing
Crushing and grinding
Primate 5 Mangrove forest, lowland
tropical rainforest south

TABLE 10.1: Type of teeth by primate

2. With your group, determine how you think the five primate species on
Kapikua may be related to one another, based on the data shared by
the primatologists. Record your group’s analysis in your science
notebook.

3. In your group, answer the following questions:

• What patterns did you notice in the data?
• What can explain the patterns that you observed?
• What other forms of evidence could be used to determine the

relatedness of the five primate species?

4. Read “Gene Analysis of the Primates on Kapikua.”

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Gene Analysis of the Primates on Kapikua

Before making recommendations about in primates; the geneticists then compared
which area of Kapikua to conserve, your team the sequences of each sample. If the
of conservationists wants even more sequences are the same, the species are closely
information about the primates who live in related; if the sequences are different, they
each area of the island. Blood samples from may be more distantly related. This process
each species were sent to a team of geneticists will add more evidence to the relatedness of
working on the island for comparative gene the primates on Kapikua.
analysis. For each sample, the geneticists
sequenced a gene responsible for blood type The geneticists presented the following
results from their analysis to your team.

SPECIES ISLAND AREA(S) DNA SEQUENCE
Primate 1 Lowland tropical rainforest north –AATGCGATTCG–
Primate 2 Lowland tropical rainforest south –TATTGGGATTCG–
Primate 3 Tropical montane cloud forest, –AATGCGATTCG–
lowland tropical rainforest north
Primate 4 Mangrove forest –AATGCGATTCG–
Primate 5 Mangrove forest, lowland tropical –AATGCGATTCG–
rainforest south

TABLE 10.2: DNA sequence for blood type by primate

5. With your group, use this new evidence to determine how you think
the five primate species on Kapikua may be related to one another.
Record your analysis in your science notebook.

6. In your group, answer the following questions:

• What patterns did you notice in the data?
• What can explain the patterns that you observed?
• The results of your analysis using the comparative anatomy data vs.

genetic data may differ. What could this mean?
7. Discuss with your group which area of the island you’d like to

conserve, based on your analysis so far. Be prepared to share your
thinking with the class.

Part B: Conserving Biodiversity on Kapikua

The first goal of Kapikua’s government is to preserve the primate species
found on the island and nowhere else. The government also wants to
preserve the biodiversity of the island and to promote sustainability.
Four forest areas are under consideration for conservation.

D-66

APPLYING EVOLUTIONARY THINKING ACTIVITY 10

8. Read about your assigned area as directed by your teacher.
9. Present a summary of your forest area to the members of your group.

As your group members present the information about their forest
areas, record the main points in your science notebook.
10. In your science notebook, write a brief summary of which forest area
you would select for conservation, based on the information you have
so far. Include an explanation of your reasoning.
11. Take part in a Walking Debate, as directed by your teacher, to share
your ideas with the class about which forest area should have
conservation priority.

Area A: Mangrove Forest

In recent years, partly because of mangrove forest degradation, the inland
areas of the island have been damaged by flooding from severe storms
that have blown in. Almost all the buildings and houses in one village
were lost to the flooding. The villagers lost their crops and homes and
had to move to other areas.

If this area is conserved, the island government plans to offer limited
permits at a reasonable cost for sustainable ecotourism to the area. For
those who live on the island,
ecotourism would provide a
number of jobs; there will be MANGROVE FOREST 3
a need for researchers, tour land area to be ­conserved (%) 14
7
guides, restaurant waiters, number of ­endemic species in the area

cooks, hotel workers, drivers, number of endemic species threatened

and boat crews, for example.
In addition, people who make
handicrafts and other goods
could earn money by selling
their wares to tourists. Park
fees would bring in revenue
that would also contribute to
the island’s economy.

FIGURE 10.3: Mangrove forest

D-67

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Currently, island residents have unlimited access to the mangrove forest for
fishing and shrimping. Some fishers have small businesses—they sell what
they catch at local markets. Others fish for recreation or to feed their
families. But if the mangrove forest is conserved, a strict catch limit will be
enforced in order to protect the food sources for a variety of organisms in
the ecosystem. The new limits could force local fishers to downsize their
businesses, which would reduce their income.

Area B: Lowland Tropical Rainforest North

A small family-run business harvests coffee from the plants the family has
grown in this forest area. The exported coffee is a desirable commodity for
people in other countries, and it is marketed as some of the best-quality
and most sustainable coffee in the world. The coffee benefits both the
family and the small number of workers hired to help with the harvest. If
the forest is designated for conservation, the family will no longer have
access to the forest for their coffee. This would mean lost income, as the
family members and workers would lose their jobs. However, the species
who live in the remaining 3% of undeveloped area will be protected.

LOWLAND TROPICAL RAINFOREST NORTH

land area to be ­conserved (%) 3
number of e­ ndemic species in the area 135
number of endemic species threatened 10

FIGURE 10.4: Lowland tropical rainforest north
D-68

APPLYING EVOLUTIONARY THINKING ACTIVITY 10

Area C: Lowland Tropical Rainforest South

Recently, a team of scientists was sent to this part of the island to research a
plant found nowhere else that shows potential as a new malaria treatment.
If the treatment is successful, it could save millions of lives. If the lowland
tropical rainforest south were conserved, the vast biodiversity of the area
would be protected, including this promising plant and other plant species
that are central to pharmaceutical research and product development.
Research scientists would be assigned permits to collect specimens in a
sustainable manner from the area. The research institute signed an
agreement with the Kapikua government that a percentage of the profit
made from products containing substances from Kapikua plants will be
funneled back into the island’s economy.

If this area is conserved, the government LOWLAND TROPICAL RAINFOREST SOUTH
plans to build a primate center to
research and protect the endemic land area to be ­conserved (%) 7
primates who live in the island forests. number of ­endemic species in the area 254
This center will also be the focus of a number of endemic species threatened 75
program to educate the public. Permits
will be available for ecotourists to visit
the center to observe the primates and
learn more about them through tours
and exhibits. However, the cost of visitor
permits for this remote area will be
much higher than the cost to tour the
mangrove forest. The primate center and
access for ecotourists will require the
construction of roads and facilities,
which will be done in the most
sustainable manner possible. For island
residents, the primate center will
provide a number of jobs, such as tour
guides, drivers, lab technicians, and
instructors.

FIGURE 10.5: Lowland tropical rainforest south

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Area D: Tropical Montane Cloud Forest TROPICAL MONTANE CLOUD FOREST 4
11
Human activities, such as logging and land area to be ­conserved (%) 5
clearing the land to plant crops, have number of e­ ndemic species in the area
degraded the cloud forest on Kapikua. number of endemic species threatened
This is a concern because during the dry
season it is important that water from
the cloud forest reaches the lower
elevations, where it is needed for
irrigation, power generation, and
drinking water. Recently, there have been
reports of pollution problems with the
water supply in another area of the
island. Because of these reports, the
government is concerned that in the
future there will not be an adequate
supply of clean water for the island. If
conserved, the cloud forest would be a
source of clean drinking water.

Two decades ago, a corporation bought a
portion of the cloud forest to develop a
large tea plantation. The tea is highly
desirable worldwide because the unique
growing conditions give it a flavor that FIGURE 10.6: Tropical montane cloud forest

people love. Currently, there is a plan
underway to expand the plantation to
meet the growing demand for the tea. If the cloud forest is conserved, the
tea plantation would not be permitted to expand, the company would not
increase its profits, and no additional jobs for islanders would be created.
However, if the area were conserved, the risk of further adverse effects on
the water cycle, climate, and organisms that depend on these resources
would be reduced. For example, the fastigo whipping frog is a rare species
that inhabits only the cloud forest. It lives in bushes close to shallow pools
of standing water, and it breeds in the standing water. If the forest area is
not conserved, the frog might be further endangered.

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APPLYING EVOLUTIONARY THINKING ACTIVITY 10

Build Understanding

1. Prepare a report to the government officials of Kapikua with your
recommendation about which area to conserve. Be sure to include the
following in your report:

• The scientific evidence and reasoning you used to determine the

best area to protect the population of primates found only on the
island

• Evidence that supports the protection of the overall biodiversity on

the island

• Evidence that supports sustainable practices on the island
• The trade-offs of your recommendation and how they relate to the

three pillars of sustainability (economic, environmental, and social)

2. Issue connection: Return to Figure 7.1 in Activity 7 (the graph of
extinction rate over time) and the possibility that we may be
experiencing a sixth mass extinction due to human activity. What role
does the creation of nature reserves, like on Kapikua, play in
addressing this possibility? What other actions might play an
important role in addressing another mass extinction?

KEY SCIENTIFIC TERMS

comparative anatomy
evolution
gene
sustainability

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11 The Evolution of Resistance

Investigative Phenomenon

In the previous learning sequence, you any, do you think humans play in this
explored why some species evolve and change? In terms of the three pillars of
others become extinct. Human actions can sustainability, how could these changes
be a major factor in how species evolve. affect humans?
Evolutionary changes in those species can
also have a direct effect on human society. In this learning sequence, you will explore
For example, since the 1990s, researchers more examples of how humans impact
and fisheries managers have documented a evolution and how those changes, in turn,
number of changes in several species of affect humans. These examples may seem
salmon. Look at the graphs in Figure 11.1. unrelated at first, but you will discover the
What do you notice about the data? What common thread that ties these examples
could explain the changes in average together: evolution by natural selection.
salmon size and age over time? What role, if

700 Average Average age in 2.8 Average age in
length 1.02 fresh water salt water (ocean)

680 (rivers and streams) 2.7
1.00
660 2.6
mm
Years
Years
640 .98 2.5
620
2.4

600 FLiagbuAreid:sEvSoEP3Ue PSBSG14I E_v0o3lutio.n936e 2.3

580 MyriadPro Reg 11 1980 1990 2000 2010 1980 1990 2000 2010

1980 1990 2000 2010 Year

Year Year

FIGURE 11.1: Average Chinook salmon size and age during stages living in fresh water and salt water

c7 m0 y0 k9 c0 m42 y92 k0 c100 m0 y20 k70 c25 m0 y15 k90

Maps1 Maps2 Maps3 Maps4 Maps5

c0 m30 y70 k0 c0 m43 y94 k0 c15 m10 y0 k85 c95 m50 y30 ko c15 m90 y90 k0

c60 m30 y100 k0 c50 m20 y75 k0 c15 m90 y90 k0 c90 m55 y40 k0 c39 m7 y12 k0

c15 m10 y0 k85 c80 m0 y0 k55 c12 m7 y0 k0 c0 m0 y0 k6 c25 m0 y15 k90

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LabAids SEPUP SGI Evolution 3e
Figure: Evo3e SB 11_03

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Like salmon, many other organisms experience evolutionary changes as a
result of human actions. Many of these changes impact human health and
our ability to produce food. For example, genetic resistance to chemicals—
such as herbicides and pesticides, which you learned about in the Genetics
unit—is particularly problematic for humans. In this activity, you will
examine the case of a patient who is seeking medical treatment for an
infection that requires the use of another kind of chemical: antibiotics.

Guiding Question

Why are microbes more difficult to eradicate now than in
the past?

Materials

FOR THE CLASS

10% bleach solution or disinfectant

FOR EACH GROUP OF FOUR STUDENTS

4 filter paper discs
permanent marker
LB agar plate
sterile swab
forceps
masking tape
metric ruler
1-mL vial of diluted yogurt culture marked “Sample”
0.5-mL vial of 1% bleach solution
0.5-mL vial of 10% bleach solution
1-mL vial of distilled water

FOR EACH PAIR OF STUDENTS

computer with Internet access

FOR EACH STUDENT

Student Sheet 11.1, “Analyzing the Model”
Student Sheet 11.2, “Testing for Resistant Bacteria”
chemical splash goggles

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