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THE EVOLUTION OF RESISTANCE ACTIVITY 11

SAFETY

Wear chemical splash goggles when working with chemicals.
Bleach permanently stains clothing. Follow the “Disinfectant
Technique for Working with Bacteria” guidelines in Part B. If there are
any spills, or if substances come into contact with your skin, notify
your teacher immediately, and wash with soap and water. Wash your
hands thoroughly at the end of the investigation.

Procedure

Part A: Tuberculosis and Its Treatment

1. Read “The Case of Carson’s Persistent Cough,” and be prepared to
share your ideas with your group.

The Case of Carson’s Persistent Cough

Carson, age 46, scheduled an he was exercising. Carson’s doctor
appointment with his doctor due ordered a series of tests, including
to a persistent cough lasting about a sputum sample and a chest
four weeks. At first Carson X-ray. Sputum is the mucus that is
thought his cough was caused by coughed up from the lower
his seasonal allergies, as it was airways in the lungs. The lab
spring. But then he noticed some analysis determined that Carson
pain in his chest when he was was positive for TB and had an
breathing deeply, especially when active TB infection in his lungs.

FIGURE 11.2: Mycobacterium tuberculosis, the
bacterium that causes tuberculosis in humans

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

2. Read “Antibiotics and Tuberculosis” to learn more about antibiotics,
which are the primary method of treating TB.

Antibiotics and Tuberculosis

The first antibiotic, penicillin, Streptomycin works by entering
was discovered in 1928 and came bacterial cells and preventing
to market in 1945. Other their ribosomes from making
antibiotics were discovered and proteins. Over the next two
developed as well during that decades, additional antibiotics
time, but the vast majority of were discovered, refined, and
antibiotics were discovered synthesized to treat TB. These
during the 1940s–1960s. This newer drugs were more effective
period is called the “golden age of than the earlier drugs in
antibiotics.” Bacterial infections shortening the period of time
that were once deadly could now that the infected person had to
be treated effectively with these take the drug. One of these
new medications. One of the first highly effective drugs, rifampin,
antibiotics developed in the works by interfering with one of
1940s to treat TB—a major the bacteria’s enzymes that is
disease in many parts of the necessary for making DNA.
world, including the United
States—was streptomycin.

3. Read “Carson’s Treatment” to learn more about Carson’s case.

Carson’s Treatment

Carson’s doctor prescribed a two months, his TB symptoms
course of antibiotics to treat were gone, so Carson decided to
Carson’s TB infection. This stop taking his antibiotics. At his
treatment required Carson to next check-up, about a month
take antibiotics every day for after stopping the medicine,
four months. The doctor Carson’s tests showed that he
also scheduled several lab still had an active TB infection.
appointments to track Carson’s After encouragement from his
recovery progress. Carson began doctor, Carson resumed taking
his course of antibiotics but the antibiotics, but his TB
soon began to experience side symptoms returned—his chest
effects—including stomach hurt again, and now he couldn’t
upset and nausea. After about exercise at all.

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THE EVOLUTION OF RESISTANCE ACTIVITY 11

4. Share your initial ideas with your group about why you think Carson’s
symptoms returned even after he restarted the antibiotics.

5. Read the following four possible explanations for why Carson’s
treatment is no longer effective. Choose what you think is the best
explanation, and record both your choice and your reason for
choosing it in your science notebook.
a. The antibiotics caused mutations in the bacterial DNA that created
a new drug-resistant strain.
b. The antibiotics exerted natural selection on the bacterial
population, allowing the existing drug-resistant strain to eventually
become the most common strain.
c. The antibiotics had no effect on the emergence of a drug-resistant
strain.
d. The antibiotics provided nutrition to the drug-resistant strain that
consumed them.

6. Follow your teacher’s instructions for gathering information from
Internet sources about antibiotic resistance and TB. The goal of your
research is to explain how bacteria become resistant to antibiotics and
why this is a problem.

7. Follow your teacher’s instructions to share what you learned with the
class.

8. Revisit Step 5 to see if your thinking about the best explanation has
changed. Record any new ideas in your science notebook.

Part B: Modeling Bacterial Resistance to Antibiotics

You have been hired as a laboratory technician to determine if Carson has
developed a form of antibiotic-resistant TB, which could explain the
recurrence of his symptoms even after resuming treatment. Follow the lab
procedure detailed below. The materials in this lab will serve as a scientific
model for the kind of test that technicians would use to test a sputum
sample, like Carson’s.

9. Read the entire procedure to familiarize yourself with the steps. Use
Student Sheet 11.1, “Analyzing the Model,” to help you understand
how this simulation models antibiotic resistance in the real world.

10. With your group, write a summary of the purpose of this activity and
the experimental design you will follow on Student Sheet 11.2,
“Testing for Resistant Bacteria.”

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Disinfectant Technique for Working with Bacteria

1. Keep all equipment away from your eyes and nose to avoid
contact with bacteria.

2. Wipe all surfaces with a disinfectant solution before and after
working with bacteria.

3. Wash your hands before and after any work with bacteria.
4. Follow all instructions for proper disposal of your materials.

11. Disinfect your table surface with disinfectant. It is important to work
on sterile surfaces during this investigation so that your agar plates do
not become contaminated.

12. Using a permanent marker, label the outside of your LB agar plate
around the outer edge of the bottom plate with your initials and the
date. Use small lettering. Draw lines on the outer side of the bottom
plate to divide the plate into quadrants. Add the following labels to
each quadrant, as shown in Figure 11.3: pos [positive]
control, neg [negative] control, Exp [Experiment]
A, Exp [Experiment] B.
13. The yogurt culture represents the 3/2on5t/r2o2l pos c
ontrol Ex
sputum sample from Carson. Dip a p B nHegCcK
sterile swab into the diluted yogurt
culture, and apply the culture to
the surface of the plate on all
quadrants except the negative
control. Tilt the lid of the plate
open just enough to add the
culture. Be sure to gently wipe the
swab on the surface of the plate.
Do not apply force that could dig
into the agar.
p A Ex
14. For your negative control, use forceps
to pick up a filter paper disc, dip the disc FIGURE 11.3: Marking the plate
in distilled water, and place it in the center of
the “neg control” quadrant.

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THE EVOLUTION OF RESISTANCE ACTIVITY 11

15. For your positive control, use forceps to pick up a second disc, dip it in
distilled water, and place it in the center of the “pos control” quadrant.

16. The 1% bleach solution represents the original antibiotic Carson was
prescribed. Use forceps to pick up a third filter paper disc and dip it
into the 1% bleach solution. Be sure that the entire filter paper is wet
but not dripping. Place the filter paper disc in the center of the
“Exp A” quadrant.

17. The 10% bleach solution represents a stronger antibiotic. Use forceps
to pick up the final filter paper disc and dip it into the 10% bleach
solution. Be sure that the entire filter paper is wet but not dripping.
Place the filter paper disc in the center of the “Exp B” quadrant.

Note: Be sure that no bleach solution gets into the “neg control” and
“pos control” quadrants.

18. Use a piece of masking tape to seal your plate. Be sure that the tape
completely covers the edge of the plate so that it cannot open.

19. Follow your teacher’s instructions about where to leave your plate
(either at room temperature or in a 37°C incubator). Be sure to place
your plate upside-down to incubate.

20. On Student Sheet 11.2, record your predictions and explain your
thinking.

21. After your bacterial culture has incubated, use a metric ruler to
measure the diameter of the zone of inhibition around each disc. The
zone of inhibition is the area around each disc where bacteria are
unable to grow, due to the presence of bleach solution that prevents
their growth. Note any bacterial colonies that are growing within this
zone. Record your observations on Student Sheet 11.2.

22. On Student Sheet 11.2, describe the results of your analysis and how
you believe antibiotic-resistant bacteria may have developed in
Carson’s case. Follow your teacher’s instructions for sharing your
results with the class.

23. Revisit Step 5 to see if your thinking about the best explanation has
changed. Record any new ideas in your science notebook.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Build Understanding

1. What was the purpose of the positive and negative controls in your lab
experiment?

2. Two students are discussing the development of new antibiotics. Sara
thinks that as new antibiotics are discovered, antibiotic-resistant
bacteria will decrease in number. Min thinks that more antibiotic-
resistant bacteria will evolve. Who do you agree with, and why?

3. From your research, describe two ways that health-care workers,
farmers, and all individuals can reduce the likelihood of infection with
antibiotic-resistant bacteria.

4. Issue connection: Why is the evolution of antibiotic resistance a major
threat to sustainability?
KEY SCIENTIFIC TERMS
antibiotic resistance
evolution
zone of inhibition

Extension

To learn more about how the discovery of antibiotics revolutionized health
care, watch the videos, "The Discovery of Penicillin" and "Producing
Penicillin," on the SEPUP SGI Third Edition page of the SEPUP website at
www.sepuplhs.org/high/sgi-third-edition.

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12 Emerging Diseases

in the last activity, you explored how populations of bacteria living

in the human body can evolve to become resistant to antibiotics and better
adapted to surviving and reproducing in that environment. In this activity,
you will explore how microbes come to use humans as hosts in the first
place. As you learned in the Unit Issue, some microbes—like the bacterium
that causes TB—evolved to become human specialists (infecting just
humans or species closely related to humans) thousands of years ago.
Other microbes, including bacteria, viruses, and protozoans, have more
recently become pathogens in humans. In fact, the rate at which new
human diseases are evolving is increasing—and this increased rate may be
due to our own actions.

FIGURE 12.1: The COVID-19 pandemic is a prime example of how new human
diseases are evolving.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Guiding Question

Why are new diseases evolving at an increasing rate?

Procedure

1. Complete the following reading which addresses the evolution of
diseases in humans.

2. Follow your teacher’s instructions for how to respond to the five Stop
to Think questions.

Reading

Epidemics and Pandemics: Past and Present

Scientists have documented cases of disease outbreaks over the course of
human history, dating back to 430 BCE (Before Common Era). Table 12.1
shows a partial list of outbreaks that have resulted in major epidemics or
pandemics. An epidemic is a disease that affects a large number of people
within a region. A pandemic is a disease that has spread across many
regions, countries, and even continents.

TABLE 12.1: Selected Important Emerging and Re-emerging Infectious Diseases, 430 BCE–2019

YEAR NAME TYPE OF DEATHS NOTES
430 BCE “Plague of Athens” PATHOGEN ~100,000 First identified transregional
Uncertain pandemic

541 Justinian plague Bacteria 30–50 Pandemic; killed half the world’s
million population

1340s “Black Death” (bubonic Bacteria ~50 million Pandemic; killed at least a quarter of
plague) the world’s population

1494 Syphilis Bacteria > 50,000 Pandemic; brought to Europe from
the Americas

1500 TB Bacteria High millions Ancient disease; became a pandemic
in the Middle Ages

1520 Smallpox Virus 3.5 million Pandemic; brought to the Americas
by Europeans

1793–1798 “The American Plague” Virus ~25,000 Colonial America
(yellow fever)

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EMERGING DISEASES ACTIVITY 12

TABLE 12.1 CONTINUED

YEAR NAME TYPE OF DEATHS NOTES
1832 Second cholera PATHOGEN 18,402 Spread from India to Europe and the
pandemic Bacteria Western Hemisphere
1918 ~50 million Led to additional pandemics in 1957,
“Great 1918” influenza Virus 1968, and 2009
First recognized in 1976; 29 regional
1976–2020 Ebola Virus 15,258 epidemics between 1976 and 2020
First recognized in 1969; became a
1981 Acute hemorrhagic Virus Rare deaths pandemic in 1981
1981 conjunctivitis Virus ~37 million Pandemic, ongoing; first recognized
HIV/AIDS in 1981
Near-pandemic
2002 SARS Virus 813 Fifth influenza pandemic of the 21st
2009 H1N1 “swine flu” Virus 284,000 century
Pandemic, mosquito-borne
2014 Chikungunya Virus Rare deaths

2015 Zika Virus ~1,000 (most Pandemic, mosquito-borne
2019 COVID-19 Virus deaths are Pandemic, ongoing (as of April 14,
fetal) 2022)
> 6,190,349

STOP TO THINK 1

What patterns do you see in the data in this table? What questions do
you have?

Host Switching

Many infectious diseases of humans are zoonotic—they are spread from
other animals to humans. Some zoonotic diseases remain specialized in
animal hosts because humans are not a suitable host for the pathogen. This
is true for the virus that causes rabies. Sometimes a pathogen can use
humans as hosts but its primary host remains another animal. But some
pathogens evolve enough that the former animal host is now unsuitable;
the pathogen can only use humans as hosts. Figure 12.2 shows these
different stages of zoonotic diseases.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY Transmission
Stage to humans
Stage 5: Only from
exclusive humans
human agent From animals
Stage 4: or (many cycles)
long outbreak humans
From animals
Stage 3: or (few cycles)
limited outbreak humans

Stage 2: Only from
primary animals
infection

Stage 1: None
agent only
in animals

Rabies Ebola Dengue HIV-1

FIGURE 12.2: Illustration of the five stages through which diseases of animals evolve to cause diseases found only
in humans. The four diseases shown (rabies, Ebola, dengue, and HIV-1) have reached different stages in the
SFiGgIuErpovenro:olSlycuGetfIirsooEsnvmoofhe1uv2om_l1uatniosnto, roatnhgeirnhgufmroamnsra).bSioelsid(satirllropwasssienddmicaatienltyrafrnosmmiasnsiiomnablsettwo eoethnesrpaenciiems,aalsn)dtothHeIVd-a1s(hneodwlipnaessed
MyriianddPircoaSteesmpiboossldib/Rleetgrualnasrm11ission.

STOP TO THINK 2

How might you use the information in Figure 12.2 to explain the different
stages of zoonotic diseases to a family member or neighbor?

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EMERGING DISEASES ACTIVITY 12

Evolution of Human Pathogens

Every organism is affected by its environment. For a pathogen, its
environment is its host’s body. When a pathogen spreads to another type of
host, it is now in a new environment. Just like with free-living organisms, a
pathogen may not have the adaptations that would allow it to survive and
reproduce in that new environment. But as you learned in the Genetics
unit, random mutations happen all the time. Sometimes an individual
pathogen will have a mutation that allows it to thrive in the new
environment—and sometimes humans are this new environment. In these
cases, the disease may spread from human to human and may eventually
spread throughout the human population. When this happens, an outbreak
(which is localized), an epidemic (which is more widespread), or even a
pandemic (which occurs across countries or continents) may occur.

A disease that affects an elm tree is highly unlikely to become a pathogen of
humans because elm trees provide such a vastly different environment for
that pathogen. The more similar another host’s environment is to the
human body, the more likely it is that the pathogen can survive in humans.
Sometimes, just a single mutation in a pathogen can make it thrive in
humans. For example, Zika—a virus that has several vertebrate hosts,
including monkeys—had never caused an epidemic or pandemic in
humans until 2015, when it suddenly became a pandemic throughout
many tropical regions, infecting millions of people. Zika caused fetal losses
and birth defects. Scientists discovered that a simple mutation causing a
change in a single amino acid allowed the Zika virus to spread rapidly and
widely across the human population. In 2019, COVID-19 is thought to
have spread from bats to humans due to mutations. Humans suddenly
became viable hosts for this virus, causing the worst pandemic in 2020
since the Great Influenza pandemic of 1918.

Many of these newly emerging diseases are caused by viruses, which have
the upper hand over humans when it comes to the speed of evolution.
First, viruses have mutation rates that are 100 to 1,000 (or more!) times
greater than in humans. This means that a mutation that allows a virus to
survive in the human body is much more likely to occur. Viruses also have
very short generation times. The increased rate of mutation plus the short
generation times means that viruses can evolve at an extremely fast rate.
As seen with COVID-19, new strains caused by new mutations are
continually arising, such as the Delta variant or the Omicron variant,
which have evolved to be more contagious. The evolution of COVID-19 is
further enabled by low vaccination rates because this gives the virus ample
hosts in which to reproduce and mutate.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

STOP TO THINK 3

Which species do you think are most likely to be the source of zoonotic
diseases in humans? Explain your reasoning.

Human Activity and Emerging Diseases

A growing body of evidence is pointing to our own activity as being at least
partially responsible for the increasing rate at which diseases of
significance are emerging. Of particular concern is deforestation. As you
learned in Activity 1: Global Forest Trends in the Sustainability unit, forests
are being cut down in many parts of the world for a variety of reasons.
When this happens, contact between humans, livestock, and wildlife
species increases, which creates more opportunities for the pathogen to
switch hosts. Another effect of deforestation is that wildlife species may go
locally extinct. They are then replaced with species such as bats and rats
that are hosts to pathogens that can spread to humans.
A team of researchers tested these ideas by collecting over 3 million records
from ecological studies throughout the world. The studies took place in all
types of habitats, ranging from native forests to farmland to urban areas.
The researchers found that the populations of species who are known to be
hosts of zoonotic disease increased as land became more disturbed. The list
of species that increased comprised 143 mammals, including bats, rodents,
and certain primates. A growing number of researchers are advocating that
ecologists and evolutionary biologists join infectious-disease researchers
and public health officials in addressing emerging diseases. This group
believes that pandemics are not just a health issue—they are an ecological
and evolutionary issue.

STOP TO THINK 4

How are deforestation, extinction, and emerging diseases related?

FIGURE 12.3: Deforestation
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EMERGING DISEASES ACTIVITY 12

Predicting the Next Pandemic

The map in Figure 12.4 shows known emerging diseases throughout the
world. Some of the diseases are newly emerging (they have never infected
humans before), and some are re-emerging (they’ve infected humans in the
past but not recently).

FIGURE 12.4: The global extent of newly emerging, re-emerging, and “deliberately
emerging” infectious diseases from 1981 to 2020.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Scientists and medical professionals are trying to predict where and when
the next diseases will emerge. Look over the map in Figure 12.4, which
shows the probability of finding an emerging disease—the brighter the color,
the higher the probability. Compare this map to the one in Figure B of the
Unit Issue. Then think back to Activity 1: Changing Landscapes in the
Sustainability unit. Do any of the patterns in deforestation or reforestation
match the patterns in this map? These are the kinds of correlations that
epidemiologists look for. If they find correlations, they begin to investigate
whether there is a cause-and-effect relationship.

FIGURE 12.5: Map showing where emerging diseases are likely to be found. The lighter
the color, the greater the probability of finding an emerging disease; the darker the
color, the lower the probability.

Recently, scientists argued that governments could reduce the risk of future
pandemics, such as COVID-19, by investing in efforts to reduce
deforestation. They also argued in favor of putting more money and effort
into monitoring, preventing, and controlling new virus outbreaks. One
team of scientists estimated that the cost of these actions would be $22
billion to $33 billion annually. This may sound like a lot, but it is actually
far less than the current cost of the COVID-19 pandemic, which is
estimated to be over $10 trillion so far, as of April 2022.

STOP TO THINK 5

If you were a scientist investigating emerging diseases due to
deforestation, where would you want to establish surveillance research?

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EMERGING DISEASES ACTIVITY 12

Build Understanding

1. Imagine that you are having a conversation with a friend or family
member about a disease outbreak. Explain to them how using
evolutionary thinking helps us understand:

• why the rate of emerging diseases is increasing
• how to predict and potentially prevent emerging diseases

2. Issue connection: How do emerging diseases affect the three pillars of
sustainability?

KEY SCIENTIFIC TERMS

epidemic
pandemic
zoonotic

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13 Shrinking Salmon

in the last two activities, you investigated how human activity can

affect the evolution of pathogens. Humans can also affect the evolution of
other organisms—which can then affect people. In this activity, you will
explore how this idea applies to a familiar context: fisheries.

Guiding Question

How is human activity affecting the evolution of salmon and
therefore the three pillars of sustainability?

Procedure

1. Review Figure 13.1. (You may recognize these graphs from Activity 11:
The Evolution of Resistance at the start of this learning sequence.) In
this activity, you will focus on Chinook salmon, which you first
learned about in the Ecology unit.

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 .96 2.3

580 1980 1990 2000 2010 1980 1990 2000 2010 1980 1990 2000 2010

Year Year Year

FIGURE 13.1: Declining body size in Chinook salmon

LabAids SEPUP SGI Evolution 3e D-91
Figure: Evo3e SB 11_03
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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

2. Read “Chinook Salmon Body Size” to learn more about body size
changes in these salmon and the evolutionary cause for this
phenomenon.

Chinook Salmon Body Size

Chinook salmon lead a migratory life. They Some salmon do not survive at sea long
are anadromous, beginning their lives in enough to begin the return upstream journey,
freshwater streams and then migrating and some salmon who begin this journey do
downstream to the ocean, a saltwater not survive long enough to make it back to
environment. They spend years at sea before the breeding grounds. This phenomenon
they return to the stream where they hatched results in strong evolutionary pressure
in order to breed. You may recall this life cycle favoring individuals with traits that increase
(which is shown in Figure 13.2) from the their probability of surviving long enough to
Ecology unit. return to reproduce. These traits are passed
on to their offspring and become more
This lifestyle requires the salmon to swim common in the population.
upstream for as many as 300 kilometers or
about 185 miles. The reason salmon go out to Starting around 1990, Chinook salmon
sea is to find enough food to become large. began making their return journeys to breed at
And the reason for becoming large, as with a younger age. Age and body size are highly
the marine iguanas, is that large male salmon correlated in salmon—the older the salmon,
are better able to compete for access to the larger it is. But now the average Chinook
females as they lay their eggs. Large females salmon is younger and smaller, both at sea and
can lay more eggs. For both males and in the freshwater streams. There are several
females, large body size leads to greater factors that may be leading to this
reproductive success. phenomenon. Two of the major factors in the

Chinook salmon die in the Salmon eggs are fertilized in
freshwater river. a freshwater river during the
Chinook salmon reproduce. fall. The following spring, the
Chinook salmon migrate
tiny sh, called fry, hatch.
back to the freshwater river Chinook salmon fry stay in
they were born in
to reproduce. the freshwater river for
Chinook salmon arrive at the about 5 months. Their
ocean, where they will survival depends on the
spend up to 8 years. quality of the river habitat.
The Chinook salmon migrate
toward the sea and smolting
begins. The process of
smolting involves the sh
going through physical
changes in order to survive
in salt water.

FIGURE 13.2: Chinook salmon life cycle

LabAids SEPUP SGI Ecology 3e
Figure: Eco3e SB 10_01
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SHRINKING SALMON ACTIVITY 13

Chinook Salmon Body Size continued

Ocean are climate change (increasing ocean food security, and they also serve as a cultural
temperatures) and increased competition from connection for some groups of people.
other fish species (both invasive species and
fish that have escaped from aquaculture). Two What are the consequences of the reduced
important factors in the freshwater streams are body size of Chinook salmon, and therefore
the quality and the depth of the water. less Chinook salmon biomass, to ecosystems
and people? Researchers have calculated that
You know from the Ecology unit that between 1990 and 2010, there was a 16%
Chinook salmon are important ecosystem reduction in Chinook salmon egg
components in the ocean and the streams production, a 28% reduction in the flow of
where they breed. Salmon are also an nutrients from salmon to other organisms, a
important commercial fish—you will find 21% reduction in commercial fisheries
salmon in many grocery stores. Salmon are earnings, and a 26% reduction in meals for
important to some rural people as a source of rural people.

3. Create a system model that helps you analyze the problem of
decreasing Chinook salmon body size. Recall from the Ecology unit
that a system model must account for and describe the following:

• The components within the system
• How the components interact with one another
• The boundary of the system being modeled, defining what is

included in the model and what is considered external to the system

Note: Boundaries do not need to be physical boundaries; they can be
conceptual or abstract. When developing your system model for the
"shrinking salmon" problem, be sure to to include components within
your conceptual boundary that address all three pillars of
sustainability.

4. Use your system model to consider the following questions:

• What might happen if salmon body size continues to decline?
• What might be done to address one or more of the problems caused

by declining salmon body size?

• What additional data or information would you want to gather to

help you understand this complex real-world problem?

5. Be prepared to share your model and ideas with the class.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Build Understanding

1. Explain how “shrinking salmon” is an evolutionary adaptation in
response to natural selection. Be sure to explain the trait that natural
selection is acting on and how a changing environment results in a
change in the frequency of that trait in the salmon population.

2. Issue connection: How does declining Chinook salmon body size
impact the three pillars of sustainability?
KEY SCIENTIFIC TERMS
adaptation
anadromous
biomass
boundary
component
natural selection
system model

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14 Mitigating Change

in this ac tivity, you will design a potential solution to the

problems caused by the evolutionary decline in salmon body size. You will
use a computer simulation to help you understand the factors affecting the
age at which Chinook salmon return to spawn in Tartoosh Creek—a
fictionalized scenario based on real-world data. You will determine how
these factors affect body size and the total amount of Chinook salmon
biomass in the system. Finally, you will consider the feasibility and
trade-offs of your potential solution from an environmental, economic,
and societal perspective.

FIGURE 14.1: Salmon are important for all three pillars of sustainability: environmental,
economic, and social.

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EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Guiding Question

How can we design a solution to the “shrinking salmon”
problem?

Materials

FOR EACH GROUP OF FOUR STUDENTS

set of Mitigation Strategies cards

FOR EACH PAIR OF STUDENTS

computer with Internet access

FOR EACH STUDENT

Student Sheet 14.1, “Salmon Simulation”
Student Sheet 14.2, “Testing Mitigation Approaches”
Student Sheet 14.3, “Mitigation Strategies Comparison”
Student Sheet 14.4, “Mitigation Plan”

Procedure

The Salmon Scenario and Simulation

1. Read “Tartoosh Creek,” a scenario about Chinook salmon on the
Olympic Peninsula of the state of Washington. Although fictionalized,
this scenario is based on real-world situations common throughout
the Pacific Northwest and British Columbia.

Tartoosh Creek

Tartoosh Creek has historically to stores and restaurants, by local
been an important spawning fishers for their own consumption,
ground for Chinook salmon. The or by Southern Resident orcas as
fish have long been a culturally their primary food source. Those
important symbol for many of the that escape capture return to
Indigenous people in the region. Tartoosh Creek to spawn, and the
After hatching in the creek, young cycle continues.
salmon swim out to Puget Sound
and the Salish Sea, where they Because of the importance of
remain for several years. While at Chinook salmon to the region, the
sea, these salmon may be caught by Tartoosh Fishing Commission has
commercial fishing boats to be sold been monitoring the fish since the
1980s. The Commission has

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MITIGATING CHANGE ACTIVITY 14

Tartoosh Creek continued

documented the decline in Chinook body on salmon body size. Because the salmon
size that you learned about in Activity 13: spend part of their lives in the ocean and
Shrinking Salmon. Because of the negative part in the creek, the Commission has
environmental, economic, and social impact identified two variables for each location.
of this smaller body size, the Commission has In the ocean, the variables are ocean
been tracking several biotic and abiotic temperature and the level of competition from
factors that may be causing the decline. invasive species of fish and fish that have
Ultimately, they hope to be able to reverse escaped from aquaculture pens. In the
this evolutionary trend. stream, the variables are water quality
(which is impacted by pollution from nearby
The Commission has compiled all of its towns) and water level (which is impacted by
data into a computer simulation to model human development in wetland areas).
the effects of four environmental variables

Fraser River British Columbia
Vancouver Washington
Island

Salish Sea
Olympic
Peninsula

Paci c Columbia River
Ocean
FIGURE 14.2: Map of the Pacific Northwest and British Columbia, where Chinook
salmon live and spawn

D-97

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

The Salmon Simulation

The salmon simulation provides • Part A examines a random
data about the change in biomass
and the distribution of size classes sample of 1,000 salmon from the
(small, medium, and large) in entire population.
salmon over time from 1980 to
2020, and projects these values into • Part B examines the entire
the future (to 2060) depending on
environmental conditions. population of salmon.

• Part C allows you to test possible

mitigation strategies based on
your results in Parts A and B.

2. Follow your teacher’s instructions for accessing the simulation at
the SEPUP SGI Third Edition student page of the SEPUP website at
www.sepuplhs.org/high/sgi-third-edition.

Part A: Factors Affecting Body Size in Salmon

In Part A of the simulation, you will examine a random sample of 1,000
salmon from the entire population. You will look at two dependent variables:

• The total biomass (kg) of 1,000 randomly sampled fish
• The size distribution of 1,000 randomly sampled fish—the percentage of

small salmon (average body size 2 kg), medium salmon (average body
size 8.5 kg), and large salmon (average body size 14 kg)

2 year old 4 year old 6 year old

FIGURE 14.3: Chinook salmon body size increases with age.

You’ll begin by exploring what has happened from 1980 to 2020.

Note: The default setting for this simulation assumes that environmental
conditions do not change moving forward—thLaabtAiidss,SEtPhUPeSGeInEvvoliurtioonn3ement will
remain in its current state into the future. Figure: Evo3e SB 14_03
MyriadPro Reg 11

You’ll explore four independent environmental variables from your system
model from Activity 13: Shrinking Salmon to see their effect on total
biomass and body size distribution:LabAids SEPUP SGI Evolution 3e two ocean variables (temperature and
Figure: Evo3e SB 14_03
MyriadPro Reg 11
competition from other species, both native and introduced) and two streamMaps1 c7 m0 y0 k9 c0 m42 y92 k0
c100 m0 y20 k70 c25 m0 y15 k90

Maps2 Maps3 Maps4 Maps5

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

variables (water quality and water depth). c60 m30 y100 k0 c50 m20 y75 k0 c15 m90 y90 k0 c90 m55 y40 k0 c39 m7 y12 k0

LabAids SEPUP SGI Evolution 3e c15 m10 y0 k85 c80 m0 y0 k55 c12 m7 y0 k0 c0 m0 y0 k6 c25 m0 y15 k90

Figure: Evo3e SB 14_03
MyriadPro Reg 11

D-98 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

MITIGATING CHANGE ACTIVITY 14

3. Use Part A of Student Sheet 14.1, “Salmon Simulation,” to guide your
exploration of the simulation. Start by exploring one environmental
variable at a time to determine its impact on both the biomass of the
randomly sampled 1,000 fish, and the percentage of fish in each size
class. Record the results on Student Sheet 14.1 Then explore the
additional factors one at a time, recording the results after each variable.

4. Discuss with your group which condition has the greatest evolutionary
impact on the age at which salmon return to spawn, and therefore
salmon body size. In other words, which environmental variable applies
the strongest natural selection favoring salmon that return to spawn at
a younger age? Be prepared to share your thoughts with the class.

Part B: Factors Affecting Salmon Populations

In Part B of the simulation, you will examine the same independent
environmental variables but this time for the entire population of salmon
instead of a random sample. You will also record an additional dependent
variable: total population size.

5. In your group, discuss why you would want to look at the entire
population of salmon vs. a sample of only 1,000.

Hint: Consider whether environmental variables can affect aspects of
the salmon population besides body size.

6. Use Part B of Student Sheet 14.1 to guide your exploration of the
simulation. Start by exploring one environmental variable at a time to
determine its impact on the total biomass of the population, the
number of fish in each size class, and the total population size. Record
the results on Student Sheet 14.1. Then explore the additional factors
one at a time, recording the results after each variable.

7. Discuss with your group the differences between your results from
Part A and from Part B.

• What differences do you notice?
• Which condition is having the greatest total impact on the salmon

population? (That is, which environmental variable is having the
greatest combined evolutionary impact and the greatest impact on
the size of the salmon population?)

• What are the implications of these differences in terms of managing

the salmon population?
Be prepared to share your results and ideas with the class.

D-99

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Part C: Designing a Solution

In Part C of the simulation, you will design a solution to address the
problems caused by the decreased biomass of the Chinook salmon
population: reduction in the flow of nutrients from salmon to other
organisms (including orcas), reduction in commercial fisheries earnings,
and reduction in meals for rural people.
8. Discuss with your group what could be done to sustain or increase the

total biomass of the salmon, drawing on your results from Part A and
Part B of the simulation. Be sure to think about sustaining or
increasing each of the following:

• The percentage of individual salmon that are classified as large
• The size of the total salmon population

9. Use Student Sheet 14.2, “Testing Mitigation Approaches,” to guide you
through Part C of the simulation, where you will explore how
mitigating the four environmental factors affects the salmon in
Tartoosh Creek.

10. In your group, discuss which mitigation approaches seem to be the most
effective. Be prepared to share your results and ideas with the class.

11. Consider this: So far you have considered only the effectiveness of a
particular approach when designing a solution. But not all solutions
are equally feasible, and the cost of mitigation strategies can vary
tremendously. If money and feasibility are also issues, how would that
impact your mitigation strategy? Discuss this with your group.

12. Obtain a set of Mitigation Strategies cards, and read through them as
a group.

13. Discuss with your group: How does reading about these specific
strategies affect how you would design a solution to this problem?
How would you balance effectiveness, cost, and feasibility?

14. Use Student Sheet 14.3, “Mitigation Strategies Comparison,” to help
you compare and contrast the different strategies. Return to the
simulation to refine possible solutions in light of the information on
the cards. Consider whether any of the factors (effectiveness, cost, and
feasibility) should be weighted more heavily in your solutions.

D-100

MITIGATING CHANGE ACTIVITY 14

15. Develop a written plan for mitigating the “shrinking salmon” problem.
Your plan should:

• include one or more of the specific suggested mitigation strategies
• address all three criteria: effectiveness, cost, and feasibility
• use the mathematical results of the computer simulation to address

the effectiveness of your proposed solution

• use the information on the cards to address the cost and feasibility

of your proposed solution

• address the trade-offs of your decision, especially in terms of the

three pillars of sustainability

Build Understanding

1. Issue connection: How does your solution address the three pillars of
sustainability? Were you able to address all three pillars equally? Did
you weigh any of the pillars more heavily than the others?

2. How confident are you that your solution will mitigate the “shrinking
salmon” problem?

3. How is the “shrinking salmon” problem similar to the problem of
antibiotic resistance and the emergence of new infectious diseases?

KEY SCIENTIFIC TERMS

adaptation
biomass
evolution
mitigating
mitigation
natural selection

D-101



15 Human Impact on Evolution

as you have seen in this unit, human activities can significantly impact
evolution, resulting in negative consequences for biodiversity and
sustainability. In some cases, there are feasible mitigation strategies that can
reduce the severity of consequences for humans and other species. In this
activity, you will create a presentation that explains how a particular human
activity impacts evolution, how resulting evolutionary changes affect
biodiversity and sustainability, and what strategies might prevent or mitigate
this negative impact. Your presentation should draw on the evidence about
evolution and human impact that you’ve collected during the unit.

Guiding Question

How can evolutionary biology be used to promote
sustainability and biodiversity?

FIGURE 15.1: Issues in sustainability affect people and biodiversity in
many ways throughout the world, including these raccoons making a
home in an abandoned truck.

D-103

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Materials

FOR THE CLASS

supplies for creating presentations
computers with Internet access

Procedure

1. Consider the human activities listed in Table 15.1, and select one to
research for your presentation.

Note: You will need your teacher’s approval of your topic before
proceeding with designing your presentation.

In addition, consider the corresponding focus questions. Your
presentation should address the focus question for your chosen human
activity. These questions are also broad and can be used as a starting
point when thinking about your presentation.

Finally, you should select a specific species to illustrate your
chosen topic.

TABLE 15.1: Potential Presentation Topics

HUMAN ACTIVITY FOCUS QUESTION

Genetically modified How does the use of genetically modified
organisms organisms affect the evolution of species?

Increasing atmospheric How does the increasing atmospheric CO2 level
CO2 level affect the evolution of crop plants?
Increasing extreme heat How do more frequent extreme heat events affect
events the evolution of species?

Hunting and/or harvesting How can hunting and/or harvesting affect the
evolution of species?

Antibiotic resistance How does antibiotic use and/or misuse lead to
the evolution of antibiotic resistance?

Emerging diseases How do human activities contribute to the
emergence and/or re-emergence of diseases?

Introduction of invasive How can the introduction of invasive species
species result in the evolution and/or extinction of
species?

Increasing human What impact does a growing human population
population have on the evolution of species?

D-104

HUMAN IMPACT ON EVOLUTION ACTIVITY 15

2. Look over the following guidelines for your presentation. Your
presentation must:

• describe your chosen human activity in terms of its impact on

evolution

• provide at least two sources of evidence (at least one from the course

materials) that support the connection between this human activity
and evolutionary changes

• explain the impact of these evolutionary changes (resulting from

this human activity) on biodiversity and sustainability

• suggest ways that humans could change their actions in order to

mitigate or prevent this negative impact
3. Listen to your teacher’s instructions about the formats you may use for

your presentation.
4. Begin gathering evidence about your topic. Review the notes in your

science notebook and other course materials. You may also conduct
online research, using reliable Internet sources.
5. Be prepared to share your presentation with the class, according to
your teacher’s instructions.

Build Understanding

1. How has your thinking about the link between human activity and
evolution changed as a result of this unit?

2. Issue connection: Based on what you’ve learned in this unit, how
would you explain the link between human activity, evolution, and
sustainability?

KEY SCIENTIFIC TERMS

biodiversity
evolution
mitigation strategies
sustainability

D-105



Unit Summary

Natural Selection and Adaptation

Individual organisms within a population typically exhibit variation in
traits. Many of these variations are heritable and are passed down from
parents to offspring. Under certain environmental conditions, some traits
may increase the survival and reproductive success of individuals. These
traits are adaptations for that specific environment, and they proliferate
from one generation to the next. For example, in times of food abundance,
large-sized marine iguanas are better able to survive and reproduce. They
pass on this trait for large body size to their offspring, and over time the
average body size of the population evolves to become large. But in times of
food scarcity, natural selection favors medium-sized individuals because
they are better able to survive, and the average body size of the population
is stabilized—both large and small iguanas are less adapted to that
environment. Behavioral traits, including social behavior, can also evolve
due to natural selection. Alarm-calling in prairie dogs is one such example.
Although individuals who give alarm calls have an increased of predation,
they save their genetic kin by making these calls, and so the trait is adaptive
because of the increased survival of these kin.

Speciation and Extinction

When evolution by natural selection occurs over a long period of time, two
populations of a single species may change so much that they eventually
become two distinct species. Species are constantly evolving as the
environment changes. For example, Anolis lizards in the Caribbean have
evolved and continue to evolve as island habitats change over time. When
environmental conditions change, some species may no longer be able to
persist, and the species goes extinct. In fact, over 99% of all species that
have ever existed on Earth have gone extinct. Thus, extinction—in addition
to speciation—is a natural process of evolution. Since the Cambrian
“explosion” 550 million years ago when life-forms began diversifying
significantly, there have been five major mass extinction events, all of
which were due to abiotic factors such as changing climate or meteor
impact. Some scientists argue that Earth is currently experiencing a sixth
mass extinction event due to human activity.

D-107

EVOLUTION SCIENCE & GLOBAL ISSUES: BIOLOGY

Evidence for Evolution

Many lines of evidence support the theory of evolution. Fossils provide
evidence about life-forms that lived in the past, from millions to billions of
years ago. Scientists can make comparisons among those fossils, and between
those fossils and living organisms, to understand patterns of evolution over
long periods of time. Comparative anatomy can be used to determine lines of
common ancestry among living and extinct organisms. Embryology
provides evidence for evolutionary relationships because embryos may
exhibit traits that are lost during development and are not present in the fully
formed organisms. More recently, genetic evidence that comes from
analyzing sequences of DNA is used to identify evolutionary relationships.
This type of evidence can yield information and identify evolutionary
relationships that cannot be found from other kinds of evidence.

Humans and Evolution

Humans both affect and are affected by evolution. Humans can change the
environment in a way that leads to evolution by natural selection of other
species. One example of this phenomenon is the evolution of antibiotic-
resistant bacteria. When humans take an antibiotic, they are changing the
bacteria’s environment. Some bacteria may be less resistant to the antibiotic
because of their genetic make-up—that is, they may have an adaptation that
gives them an advantage over bacteria without that trait. These resistant
bacteria then proliferate. This creates a problem for people because the
antibiotic stops working, and they remain sick. Another example of this
phenomenon is the evolution of new diseases. Humans alter the
environment by, for example, cutting down forests, which puts people in
closer contact with animal species that carry diseases. Some of these disease-
causing organisms have a genetic trait that allows them to infect and survive
in humans. These individuals proliferate, and the disease may spread from
person to person, possibly leading to an epidemic or a pandemic.
Some of these evolutionary interactions can affect the sustainable use of an
important natural resource. For example, human modification of the
environment has led to natural selection favoring salmon returning to
spawn in streams at a younger age, which means that salmon are
“shrinking.” This reduced biomass of salmon affects all three pillars of
sustainability: Environmentally, there is less energy and matter in the
salmon’s ecosystem, which can affect species that feed on them, such as
orcas. Economically, commercial fishers cannot catch as much salmon, so
they earn less money. Socially, rural people who rely on salmon for their
main source of protein have less to eat. Understanding how people are
affecting the evolution of other species can be essential for mitigating the
problems caused by these changes.

D-108

MANAGING CHANGE SUMMARY

KEY SCIENTIFIC TERMS gene pool
genes
adaptation genetic variation
anadromous homologous genes
Anthropocene kin
antibiotic resistance mass extinction event
biodiversity mitigating
biological species mitigation
biological species concept mitigation strategies
biomass mutation
boundary natural selection
carrier pandemic
climate change photosynthesis
comparative anatomy population
competition scientific theory
component sixth mass extinction
DNA social behavior
ecological speciation
embryology species
embryos sustainability
epidemic system model
evolution theory of evolution
extinction zone of inhibition
fossil record zoonotic
gene
gene flow

D-109



Appendices

A Literacy Strategies XA-1
XA-2
“Read, Think, and Take Note” Reading Strategy XA-3
Reading Scientific Procedures XA-4
Writing Frames XA-4
• Constructing Explanations XA-5
• Engaging in Argument from Evidence
• Evidence and Trade-Offs XA-6
• Planning and Carrying Out Investigations
Writing Review XA-7
XA-8
B Science and Mathematics Skills
XB-1
Elements of Good Experimental Design XB-2
Graphing Data XB-3
Interpreting Graphs XB-6
Keeping a Science Notebook XB-11
Reading a Graduated Cylinder XB-12
Using a Dropper Bottle XB-13
Using a Microscope XB-14

C Assessment in SGI XC-1
XC-2
Analyzing and Interpreting Data (aid) XC-3
Communicating Concepts and Ideas (com) XC-4
Constructing Explanations (exp)  XC-5
Developing and Using Models (mod) 

X-1

APPENDICES SCIENCE & GLOBAL ISSUES: BIOLOGY

Engaging in Argument from Evidence (arg)  XC-6
Evidence and Trade-Offs (e&t)  XC-7
Planning and Carrying Out an Investigation (pci) XC-8

D Guidelines for Safety XD-1
in the Science Classroom
XE-1
E Group Interactions XE-2
XE-3
Developing Communication Skills XE-4
Evaluating Group Interactions
Group Interactions Classroom Rubric  XF-1
XF-2
F Science References XF-4
XF-21
International System of Units XF-22
Classifying Living Organisms XF-23
Elements and Organisms
Periodic Table of Elements XG-1
The Geologic Timescale
XH-1
G Crosscutting Concepts XH-2
XH-6
H Media Literacy
XI-1
Media Literacy: An Overview
Evaluating Websites

I Science as a Human Endeavor

X-2

A: Literacy Strategies

“Read, Think, and Take Note” Reading Strategy XA-2
Reading Scientific Procedures XA-3
Writing Frames XA-4
• Constructing an Explanation XA-4
• Engaging in Argument from Evidence XA-5
• Evidence and Trade-Offs
• Planning and Carrying Out Investigations XA-6
Writing Review
XA-7
XA-8

XA-1

APPENDICES SCIENCE & GLOBAL ISSUES: BIOLOGY

”Read, Think, and Take Note” Reading Strategy

Stop at least three times during the reading to mark on a sticky note your
thoughts and questions. Use the guidelines below to start your thinking.

Read, Think, and Take Note Guidelines

As you read, use a sticky note from time to time to:
• E xplain a thought or reaction to something you read
• N ote something in the reading that is confusing or unfamiliar
• L ist a word from the reading that you do not know
• D escribe a connection to something you've learned or read previously
• Make a statement about the reading
• P ose a question about the reading
• Draw a diagram or picture of an idea or connection
After writing a thought or question on a sticky note, place it next to the
word, phrase, sentence, diagram, drawing, or paragraph in the reading that
prompted your note.

XA-2

A: LITERACY STRATEGIES APPENDICES

Reading Scientific Procedures

The purpose of reading a scientific procedure is to find out exactly what to do,
when to do it and with what materials, in order to complete all the steps of an
investigation.

If you read a step and are not sure what to do, try these strategies:
• Reread the previous step.
• Reread the step that confuses you. Sometimes rereading clarifies
the information.
• Ask your partner if he or she understands what the step says to do.
• Ask your partner if there are words you don’t understand.
• Ask your partner to explain what the step says to do.
• Ask your partner to read the step aloud as you listen and try to do
what your partner is describing.
• Reread the purpose (guiding question) of the investigation.
• Try to say the purpose of the step out loud in your own words.
• Look at the clues in the pictures of the activity.
• Peek at other groups and listen to see if they are doing the step that
confuses you.
• Tell your teacher exactly what you are confused about and why it
doesn’t make sense.

XA-3

APPENDICES SCIENCE & GLOBAL ISSUES: BIOLOGY

Writing Frame—Constructing Explanations

I am explaining ___________________________________________________________________
_ _________________________________________________________________________________
_ _________________________________________________________________________________
The first line of evidence related to my explanation is __________________________________
__________________________________________________________________________________
_ _________________________________________________________________________________
__________________________________________________________________________________
My reasoning for how and why this evidence leads to my explanation is that _____________
__________________________________________________________________________________
_ _________________________________________________________________________________
_ _________________________________________________________________________________
The second line of evidence related to my explanation is ______________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
My reasoning for how and why this evidence leads to my explanation is that _____________
__________________________________________________________________________________
_ _________________________________________________________________________________
_ _________________________________________________________________________________
The third line of evidence related to my explanation is ________________________________
_ _________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
My reasoning for how and why this evidence leads to my explanation is that _____________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________

In conclusion, _____________________________________________________________________
_ _________________________________________________________________________________
__________________________________________________________________________________

XA-4

A: LITERACY STRATEGIES APPENDICES

Writing Frame—Engaging in Argument from Evidence

I am arguing for the claim that ______________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________

The first line of evidence that supports my claim is ____________________________________
__________________________________________________________________________________
__________________________________________________________________________________

My reasoning for how/why this evidence supports my claim is that _________________
_ _________________________________________________________________________________
_ _________________________________________________________________________________
_ _________________________________________________________________________________

The second line of evidence that supports my claim is _______________________________
_ _________________________________________________________________________________
__________________________________________________________________________________

My reasoning for how/why this evidence supports my claim is that __________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________

The third line of evidence that supports my claim is _________________________________
__________________________________________________________________________________
__________________________________________________________________________________

My reasoning for how/why this evidence supports my claim is that __________________
__________________________________________________________________________________
__________________________________________________________________________________
_ _________________________________________________________________________________

People who do not support my claim might say _____________________________________
_ _________________________________________________________________________________
_ _________________________________________________________________________________

but I disagree with them because __________________________________________________
_ _________________________________________________________________________________

XA-5

APPENDICES SCIENCE & GLOBAL ISSUES: BIOLOGY

Writing Frame—Evidence and Trade-Offs

There is a lot of discussion about the issue of ___________________________________________
_______________________________________________________________________________

My decision is that _______________________________________________________________
_______________________________________________________________________________
My decision is based on the following evidence:

First, __________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

Second, ________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

Third, _________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

The trade-off(s) __________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

People who disagree with my decision might say that ____________________________________
_______________________________________________________________________________
_______________________________________________________________________________

XA-6

A: LITERACY STRATEGIES APPENDICES

Writing Frame—Planning and Carrying Out an Investigation

The purpose of my investigation is to: ______________________________________________
The variable I am testing is: ______________________________________________________
The variables I will keep the same are: ______________________________________________
I will need the following materials: _________________________________________________
Qualitative data I will collect include: ______________________________________________
Quantitative data I will collect include: _____________________________________________
My hypothesis is: ______________________________________________________________
My procedure steps are:
1.
2.
3.
I will record the data in the following table:

My conclusion is: _______________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________

The evidence and reasoning that led me to this conclusion are: ____________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________

XA-7

APPENDICES SCIENCE & GLOBAL ISSUES: BIOLOGY

Writing Review

Use the following questions to review someone else’s writing. Answer the questions after
you have read or heard the person’s answer twice.

Name of the person whose writing you reviewed:
____________________________________________________________________________________
State the topic of the writing:
____________________________________________________________________________________
____________________________________________________________________________________
Are the facts clear and accurate? _________________________________________________________
If you answered “no,” which facts need to be more clear or need correction?
If you answered “yes,” which facts are presented clearly and accurately?
____________________________________________________________________________________
_ ___________________________________________________________________________________
_ ___________________________________________________________________________________
_ ___________________________________________________________________________________
Do the facts support the writer’s position? _________________________________________________
If you answered “no,” which facts do not support the writer’s position?
If you answered “yes,” which facts support the writer’s position?
_ ___________________________________________________________________________________
_ ___________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
List any statements or ideas that the writer did not support with facts.
____________________________________________________________________________________
_ ___________________________________________________________________________________
_ ___________________________________________________________________________________
_ ___________________________________________________________________________________
Do you agree with the writer’s conclusion? Explain why or why not.
____________________________________________________________________________________
_ ___________________________________________________________________________________

XA-8

B: Science and Mathematics Skills

Elements of Good Experimental Design XB-2
Graphing Data XB-3
Interpreting Graphs XB-4
Keeping a Science Notebook XB-11
Reading a Graduated Cylinder XB-12
Using a Dropper Bottle XB-13
Using a Microscope XB-14

XB-1

APPENDICES SCIENCE & GLOBAL ISSUES: BIOLOGY

Elements of Good Experimental Design

An experiment that is well-designed:
• builds on previous research
• is based on a question, observation, or hypothesis
• describes all steps in a procedure clearly and completely
• includes a control for comparison
• keeps all variables—except the one being tested—the same
• describes all data to be collected
• includes precise measurements and records of all data collected during the

experiment
• may require multiple trials
• can be reproduced by other investigators
• respects human and animal subjects
Note: These elements may vary depending on the problem being studied.

XB-2

B: SCIENCE AND MATHEMATICS SKILLS APPENDICES

Graphing Data

Follow the instructions below to graph your data.

Choose the Best Type of Graph for Your Data

1. E xamine your data table, and determine if your data is best represented by a bar
graph, a line graph, or a scatterplot.

• Bar graphs are generally used to compare groups or to show large changes over
time (see the example in Table A).

• Line graphs are generally used to show changes over time, especially if the
changes are small (see the example in Table B).

• Scatterplots are generally used to show relationships between two variables, one
on the x-axis and one on the y-axis (see the example in Table C).

Table A: Appropriate Data for a Bar Graph

Per-Person Meat Consumption by Country in 2017

COUNTRY PER-PERSON MEAT
Brazil CONSUMPTION (KG), 2017
India
Kenya 109
United States 11
Vietnam 20
146
101

Table B: Appropriate Data for a Line Graph

Temperature of Sample A and Sample B Over Time

TIME (S) TEMPERATURE TEMPERATURE
0 (°C) OF SAMPLE A (°C) OF SAMPLE B
10
20 18 18
30 22 15
40 26 12
28 10
29 8

XB-3

APPENDICES SCIENCE & GLOBAL ISSUES: BIOLOGY

Graphing Data (continued)

Table C: Appropriate Data for a Scatterplot

Body Size Vs. Age in Species X

AGE (YRS) BODY SIZE (KG)
1 2
2 5
3 9
4 13
5 18

Set Up Your Graph

2. Draw the x- and y-axes for the graph. Label them with the names and units of the data.

3. Decide on a scale for each axis. Be sure there is enough space for all the data and that
the data points are not too crowded.

4. M ark intervals on the graph, and label them clearly.

150 30 30
Per-Person Meat Consumption (kg)
Brazil 25
India
Kenya
United States
Vietnam

Temperature ( °C)
125 25

100 20 Body Size (kg) 20

75 15 15

50 10 10

25 5 5

0 0 0 10 20 30 40 50 00 1 2 3 4 5

Time (seconds) Age (years)

Country

PePr-lPoetrsYonoMueraDt Caotnasumption by Country in 2017

5. P lac1e50your data points on the graph.
6. I poffoytionh11u5702te5005s’vpweoicitnrhetsaa.tseImfditao’sobatahsrclgianrtateeporhpr,lcfoiultl,rivlneeattvhheeattbhfaeorldsl.oaItwfasiptt’sohiaenlptisnautetnegrcrnoapnihnn,deccicotaentdne.decbtyththeedpatoasition

25
0
Per-Person Meat Consumption (kg)
Brazil
India
Kenya
United States
Vietnam

XB-4 Country
Temperature of Sample A and Sample B Over Time