Evolution 3e TE v5

©2017 The Regents of the University of California

early stage VISUAL AID 13.3

WHOLE EMBRYO SORTING

middle stage

late stage

bat chicken salmon human snake

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14 The Sixth Extinction?
talking it over
2 class sessions

ACTIVITY OVERVIEW

NGSS CONNECTIONS
Students analyze and interpret patterns of large-scale extinctions over the entire
history of Earth, and identify the five mass extinctions detected by scientists.
Students compare the possible causes of those extinctions, and learn that there
may be multiple causes. They analyze data on the current rate of extinction and
engage in argument based on evidence about whether there is currently a sixth
mass extinction caused by human activity.

NGSS CORRELATIONS

Performance Expectations
Working towards MS-ESS3-4: Construct an argument supported by evidence
for how increases in human population and per-capita consumption of natural
resources impact Earth’s systems.
Working towards MS-LS4-5: Gather and synthesize information about the
technologies that have changed the way humans influence the inheritance of
desired traits in organisms.
Applying MS-LS4-1: Analyze and interpret data for patterns in the fossil record
that document the existence, diversity, extinction, and change of life forms
throughout the history of life on Earth under the assumption that natural laws
operate today as in the past.

Disciplinary Core Ideas
MS-LS4.A Evidence of Common Ancestry and Diversity: The collection of fossils and
their placement in chronological order (e.g., through the location of the sedimen-
tary layers in which they are found or through radioactive dating) is known as the
fossil record. It documents the existence, diversity, extinction, and change of many
life forms throughout the history of life on Earth.

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ACTIVITY 14  THE SIXTH EXTINCTION?

MS-ES3.C Human Impacts on Earth Systems:

Human activities have significantly altered the biosphere, sometimes damaging
or destroying natural habitats and causing the extinction of other species. But
changes to Earth’s environments can have different impacts (negative and positive)
for different living things.

Typically as human populations and per-capita consumption of natural resources
increase, so do the negative impacts on Earth unless the activities and technologies
involved are engineered otherwise.

MS-LS4.D Biodiversity and Humans: Changes in biodiversity can influence
humans’ resources, such as food, energy, and medicines, as well as ecosystem
services that humans rely on—for example, water purification and recycling.

MS-LS4.B Natural Selection: Natural selection leads to the predominance of
certain traits in a population, and the suppression of others. In artificial selection,
humans have the capacity to influence certain characteristics of organisms by
selective breeding. One can choose desired parental traits determined by genes,
which are then passed on to offspring.

Science and Engineering Practices

Analyzing and Interpreting Data: Analyze and interpret data to determine
similarities and differences in findings.

Engaging in Argument from Evidence: Use an oral and written argument supported
by evidence to support or refute an explanation or a model for a phenomenon.

Crosscutting Concepts

Patterns:
Patterns can be used to identify cause and effect relationships.
Graphs, charts, and images can be used to identify patterns in data.

Cause and Effect:

Cause and effect relationships may be used to predict phenomena in natural or
designed systems.

Phenomena may have more than one cause, and some cause and effect
relationships in systems can only be described using probability.

Connections to Nature of Science: Science Knowledge Assumes an Order and Consistency
in Natural Systems: Science assumes that objects and events in natural systems
occur in consistent patterns that are understandable through measurement and
observation.

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THE SIXTH EXTINCTION? ACTIVITY 14

Connections to Nature of Science: Science Addresses Questions About the Natural and
MaterialWorld: Scientific knowledge can describe the consequences of actions but
does not necessarily prescribe the decisions that society takes.

Common Core State Standards—ELA/Literacy
RST.6-8.7: Integrate quantitative or technical information expressed in words in
a text with a version of that information expressed visually (e.g., in a flowchart,
diagram, model, graph, or table).
W.6-8.9: Draw evidence from literary or informational texts to support analysis,
reflection, and research.

WHAT STUDENTS DO
Students examine a graph showing rates of extinction over time and identify
episodes where rates of extinction were well above the background rate of
extinction. They match information on cards about the five major extinction events
identified by scientists to the graph. They also summarize the possible causes for
these extinctions. Students then read about rates of extinction since 1500 and
examine possible causes for those extinctions. Students consider whether there is
currently a sixth mass extinction due to humans and, if so, whether people should
do anything to prevent it.

MATERIALS AND ADVANCE PREPARATION

■■ For the teacher

1 Visual Aid 14.1, “Possible Extinction Rates Over Time”
1 Scoring Guide: engaging in argument from evidence (arg)
1 Scoring Guide: evidence and trade-offs (e&t)

■■ For each group of four students

1 set of 5 Extinction Event Cards
1 Student Sheet 14.1, “Past Extinction Rates”

■■ For each student

1 Scoring Guide: engaging in argument from evidence (arg) (optional)
1 Scoring Guide: evidence and trade-offs (e&t) (optional)

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ACTIVITY 14  THE SIXTH EXTINCTION?

TEACHING SUMMARY

GET STARTED

1. Students consider if or how the rate of extinction varies over time.
a. Show Visual Aid 14.1, “Possible Extinction Rates Over Time,” and ask
students to choose the graph that they think is most likely to resemble
what scientists have learned about how the rate of extinction varies
over time.
b. Have students read the introduction.
This is a good time to revisit the last driving question. Revisit and add to
or revise students' ideas as needed.

DO THE ACTIVITY
2. Students examine rates of extinctions over time.

a. Distribute Student Sheet 14.1, “Past Extinction Rates,” and direct
students to review the graph that appears on the Student Sheet and in
Procedure Step 1.

b. Have a brief class discussion for students to share if they have identified
any periods of time when extinctions were especially high.

3. Groups match the five Extinction Event Cards to peaks on the graph.
a. Pass out a set of Extinction Event Cards to each group.
b. Direct students to Procedure Steps 3–5.
c. Facilitate a whole-class discussion about the five extinction events.

4. Students read about the rates of extinction from the year 1500 to the present.
a. Direct students to Procedure Steps 6 and 7.
b. After pairs have had a chance to examine the graph, have a class discus-
sion of recent patterns of extinction.

5. Students look at evidence about the causes of bird extinctions since 1500.
a. Direct students to Part C to read and examine the pie charts about causes
of bird extinctions.
b. Help students look for patterns in the pie charts.

BUILD UNDERSTANDING
6. Students discuss Procedure Steps 9–10.

a. Ask the class how the causes of these extinctions compare and contrast
with the causes of the previous five extinction events.

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THE SIXTH EXTINCTION? ACTIVITY 14

b. Instruct students to discuss in their groups whether we are currently
experiencing a sixth major extinction event.

c. Have students share their arguments with the class.
7. Students respond to the Analysis.

a. Direct students to Analysis item 1, which makes connections to the earlier
activity, “Fossil Evidence.”

b. (arg assessment) Let students know they will be assessed on Analysis
item 2 about whether or not they believe we are experiencing a sixth
extinction.

c. Direct students to Analysis item 3 about how a sixth extinction might
affect people.

8. (e&t quick check). In Analysis item 4, students consider whether anything
should be done to reduce the current rate of extinction.
a. Introduce the idea that decisions about solutions to scientific and engi-
neering problems often involve trade-offs.
b. Provide an example of trade-offs.
c. Project the evidence and trade-offs (e&t) Scoring Guide.

TEACHING STEPS

GET STARTED
1. Students consider if or how the rate of extinction varies over time.

a. Show Visual Aid 14.1, “Possible Extinction Rates Over Time,” and ask
students to choose the graph that they think is most likely to resemble what
scientists have learned about how the rate of extinction varies over time.
Ask students to describe what each graph shows about the extinction
rate. Be sure they understand that the graphs show (a) a constant rate of
extinction, (b) an increasing rate of extinction, (c) a decreasing rate of
extinction, and (d) fluctuating rates of extinction. Ask a few students to
explain their reasoning for their responses. Some might think the extinc-
tion rate has stayed the same; others might suggest that as more species
have evolved, there are more to become extinct; and still others might
think the rate has changed depending on other events on Earth. Many
students will probably have little information upon which to base their
answers, so accept all reasonable responses at this point.

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ACTIVITY 14  THE SIXTH EXTINCTION?

b. Have students read the introduction.

Remind students that virtually all species that have ever evolved will go
extinct, and species continue to go extinct through the present day. This
reinforces the nature of science idea that natural laws operate today the
same way they did in the past.302

DO THE ACTIVITY

2. Students examine rates of extinctions over time.

a. Distribute Student Sheet 14.1, “Past Extinction Rates,” and direct
students to review the graph that appears on the Student Sheet and in
Procedure Step 1.303304305

Point out that this graph begins 600 mya, which corresponds with the
Cambrian explosion that they learned about in the earlier activity, “History
and Diversity of Life.” It ends at a point shortly before the present. Have
students compare it with the graphs on Visual Aid 14.1. They should
realize that the pattern is closer to Graph D than any of the others.

b. Have a brief class discussion for students to share if they have identified
any periods of time when extinctions were especially high.

Explain that they should compare the rate of extinction to the background
rate of extinction, which is like an average. They are likely to identify four
to six peaks, depending on whether they identify the peaks at 400 mya and
approximately 180 mya as significantly higher than the background.

3. Groups match the five Extinction Event Cards to peaks on the graph.

a. Pass out a set of Extinction Event Cards to each group.

Explain that scientists have identified five major bursts or waves of extinc-
tion in the past, and each one is described on one of the cards.

b. Direct students to Procedure Steps 3–5.

Students begin by matching the cards to peaks on the graph. This will be
relatively straightforward as students can use the dates on the cards to
match them to peaks.

Circulate throughout the room as groups are reading the cards to help
with any challenging terms. Encourage them to look for similarities and
differences between the reasons for the five extinction events. Listen for
groups who have identified interesting patterns so that you might ask
them to share with the class.

302 NGCCNS3
303 NGLS4A1
304 NGCCPA1
305 NGCCPA2

200 EVOLUTION

THE SIXTH EXTINCTION? ACTIVITY 14

c. Facilitate a whole-class discussion about the five extinction events.306307308

Have the pre-selected groups share patterns they see about the causes for the
five extinctions, and invite other groups to respond. If needed, help students
arrive at the observation that all of the extinctions were due to major physical
catastrophes: volcanoes, meteors, glaciers, climate change, etc.

If students are having difficulty with Procedure Step 5, you might model
for them how you estimate the magnitude of the second extinction. Say,
“If we divide the green portion of the line under that point into four
equal quarters, the portion that extends above the green until the peak is
about one more quarter. So the rate of extinction is about 1.25 times the
background rate.” OR “If we divide the peak value of about 9 families per
million years by the background rate of about 7 families per million years,
we find the rate of extinction is about 1.28 (or 1.3) times the normal rate.”

Students should be able to estimate that the number of families lost
during the fifth great extinction is about 3 times the background rate.

4. Students read about the rates of extinction from the year 1500 to the
present.309310

a. Direct students to Procedure Steps 6 and 7.

Whereas Part A looked at rates of extinction in the distant past, this graph
looks at rates of extinction from the more recent past—from 1500, the
start of the European expansion, to the present. Help students realize that
while both graphs look at rates of extinction, the previous graph looks
at extinction of families of all types of organisms and this graph looks at
extinction of species of vertebrates only. Although they do not represent the
same variables, both graphs look at the rate of extinction compared with
the background rate, so the graphs can be compared with one another.

b. After pairs have had a chance to examine the graph, have a class discus-
sion of recent patterns of extinction.311312313

Ask pairs to share what patterns they detected and whether they have
some explanation for the cause(s) of the patterns.

306 NGCCCE1 The rate of extinction of mammals was higher than for other verte-
307 NGCCCE2 brates at the start of the time period and remained higher than for the
308 NGES3C2 other types of vertebrates, increasing sharply at around the year 1800.
309 NGLS4B2 Bird extinctions began to rise around 1600 and then continued to rise.
310 NGES3C1 Extinction of other vertebrates was at or below the background rate until
311 NGCCPA2 around 1800, when it increased steeply.
312 ELRS687
313 ELWH689 EVOLUTION  201

ACTIVITY 14  THE SIXTH EXTINCTION?

Students might speculate that people hunted mammals for food, and then
as those started going extinct, they started to hunt birds. Students might
also speculate that the loss of other kinds of vertebrates may be due to
some other factor, since it remained so low for so long, and then suddenly
went up.

Another way to make sense of the current rate of extinction is to ask how
long this number of extinctions would have taken if they occurred at the
background rate. The Student Book explains that it would have taken
around 5,000 years. Given that the actual time was 500 years, this means
the current rate of extinction is 10 times the background rate.

5. Students look at evidence about the causes of bird extinctions since 1500.314315316

a. Direct students to Part C to read and examine the pie charts about causes
of bird extinctions.

The reading explains why the data for birds are relatively complete and
thus easiest to analyze. Remind students that patterns and cause-and-effect
are both crosscutting concepts that help scientists explain phenomena.
Scientists look for patterns in order to identify cause-and-effect
relationships. These pie charts reveal patterns in bird extinctions over time.

b. Help students look for patterns in the pie charts.

The charts show that the initial causes for extinction were due largely to
hunting and the introduction of invasive species. Over time, the causes
diversified, and a greater proportion went extinct due to habitat destruc-
tion or modification (as a result of agriculture, development, and other
human activities) or global change, such as global warming that has
altered habitats everywhere.

BUILD UNDERSTANDING

6. Students discuss Procedure Steps 9–10.

a. Ask the class how the causes of these extinctions compare and contrast
with the causes of the previous five extinction events.

Students are likely to recognize that the extinctions since the year 1500
are largely caused by human activity (e.g., hunting, invasive species
introduced intentionally or unintentionally, habitat modification, global
climate change). This is in contrast to the first five extinctions, which were
all caused by abiotic, or physical, factors unrelated to human activity.

b. Instruct students to discuss in their groups whether we are currently
experiencing a sixth major extinction event.

314 NGLS4B2
315 NGLS4D1
316 NGSPAD4

202 EVOLUTION

THE SIXTH EXTINCTION? ACTIVITY 14

Point out to students they that will use the scientific practice of engaging
in argument from evidence when discussing this question. They must use
evidence presented in this activity to support their answers.

c. Have students share their arguments with the class.

Consider having a Walking Debate around this question. Designate one
side of the room as “Yes, we are experiencing a sixth extinction,” and the
other side of the room as “No, we are not experiencing a sixth extinction.”
Have students stand in the place that they believe is the best claim. If
most of the students already agree that we are in a sixth extinction, you
may want to assign some of them to the other option to foster the skills of
debate and evidence analysis.

Have students in each area talk among themselves to create a convincing
evidence-based argument that will bring students from the other areas to
their own area. They may also develop questions to ask the other groups.
Have each group present its argument and respond to any questions. After
both groups have spoken, each student individually decides which was
the most convincing argument by moving to the area that represents their
final position. For more information on Walking Debates, see the Literacy
section of Teacher Resources II, “Diverse Learners.”

7. Students respond to the Analysis.

a. Direct students to Analysis item 1, which makes connections to the earlier
activity, “Fossil Evidence.”

Two of the fossils that students examined, a trilobite and an ammonite,
went extinct in the third and fifth extinctions, respectively. Students can
arrive at this answer in two ways. First, this information is stated on the
cards in this activity. However, encourage students to corroborate this
evidence using a second method: in the earlier activity, “Fossil Evidence,”
students inferred when these trilobites and ammonites went extinct by
determining the age of the last layer of rock in which the fossils were
found. They can find age on the graph of the five extinctions in this
activity to determine if either or both of these groups went extinct in one
of the five major events. 317

b. (arg assessment) Let students know they will be assessed on Analysis
item 2 about whether or not they believe we are experiencing a sixth
extinction. 318

Having discussed this in their groups and as a class, students now make
their final arguments in writing to support their answers. Let students

317 NGLS4A1
318 SEASAR1

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ACTIVITY 14  THE SIXTH EXTINCTION?

know that they will be scored using the arg Scoring Guide. Project the
guide, or refer them to the guide they received in the earlier activity
“Fossilized Footprints,” as they construct their responses.

c. Direct students to Analysis item 3 about how a sixth extinction might
affect people.319

Encourage students to write an initial response in their science notebooks
and then share it with their partners. Invite students to share their ideas
during a class discussion.

The purpose of this question is to encourage students to think about
the ways in which people use and benefit from biodiversity. If species go
extinct, we may lose some of those benefits. For example, many medi-
cines were originally derived from plants. If plants go extinct, we lose any
potential products that might be developed from those plants. If wild vari-
eties of crops go extinct, and then a pest wipes out the cultivated varieties,
we can’t develop new varieties that are resistant to pests.

The activity can also be used to point out trends in the human population
that may be important in considering the magnitude of a sixth extinction.
Point out that in the year 1500, the entire human population was around
540 million people; today there are over 7.5 billion people. Ask students
to consider what might happen if this trend continues.

If students are interested in exploring more ways by which humans benefit
from biodiversity that would be at risk in the sixth extinction, encourage
them to visit some of the resources found on the SEPUP website.

8. (e&t quick check) In Analysis item 4, students consider whether anything
should be done to reduce the current rate of extinction. 320

a. Introduce the idea that decisions about solutions to scientific and engi-
neering problems often involve trade-offs.

This unit includes issues that relate to science and/or technology and that
may lead to decisions about the best solutions for solving problems. One
goal of this curriculum is to teach students that

• decisions about possible solutions often involve trade-offs.

• identifying trade-offs involves analyzing evidence.

In this activity, students must decide whether anything should be done
to reduce the current rate of extinction. In a decision involving trade-
offs, something is given up to gain something else. Since many decisions
involve trade-offs, students should understand that a perfect choice is

319 NGLS4D1
320 NGCCNS4

204 EVOLUTION

THE SIXTH EXTINCTION? ACTIVITY 14

often not possible. It is possible, however, to recognize and analyze the
trade-offs associated with each decision.

b. Provide an example of trade-offs.

For example, when asked, “Paper or plastic?” at a store checkout counter,
most shoppers make the choice quickly. But there are several trade-offs
attached to choosing paper or plastic. A shopper who chooses paper over
plastic may do so to avoid generating plastic waste. In requesting the
paper bag, though, they are contributing to other environmental prob-
lems, such as increased water and energy use, and the higher amounts
of solid waste and carbon dioxide emissions associated with making
paper bags. Neither choice is ideal, and both choices have a downside.
Identifying the trade-offs helps clarify the reasoning that is being applied
to make a decision.

c. Project the evidence and trade-offs (e&t) Scoring Guide.

Explain that students will not be scored on their response to Analysis
item 4, but in a later activity, they will be scored using this Scoring Guide.
Review the levels, which are similar to those in other Scoring Guides.

After giving students time to think about the question individually and in
groups, have a class discussion about the question of whether something
should be done to reduce the rate of extinction. In contrast to the practice
of engaging in argument from evidence, where all of the evidence is scien-
tific, in evaluating trade-offs, students may use evidence and/or reasoning
from other perspectives, including economics, politics, and other social
sciences. Thus, accept all reasonable responses to this question. For
example, some students may say that something should be done because if
it is not, humans may suffer due to the loss of biodiversity. Other students
may argue that it isn’t necessary to do anything because we have always
been able to use technology to solve our problems, and we would be
limiting society’s ability to grow and develop now. This is an opportunity
to reinforce connections to the nature of science: Scientific knowledge can
describe the consequences of actions but does not necessarily prescribe
the decisions that society takes.

SAMPLE RESPONSES TO ANALYSIS

1. In the activity “Fossil Evidence,” you examined fossils of organisms that have
gone extinct. Did any of them go extinct during the five extinction events? If
so, during which events did the extinctions occur? If not, when on the timeline
did they go extinct?

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ACTIVITY 14  THE SIXTH EXTINCTION?

Yes, we discovered that trilobites went extinct during the third extinction, and ammo-
nites went extinct during the fifth extinction.

2. (arg assessment) Are we experiencing a sixth extinction? Be sure to use
scientific evidence from this activity (and elsewhere in the unit) to support
your claim. 321322

SAMPLE LEVEL-4 RESPONSE

My claim is that we are experiencing a sixth extinction.The evidence to support my
claim is that the current rate of extinction of birds is 10 times greater than the back-
ground rate of extinctions.This increased rate is much higher than any of the other
five extinction events that scientists have identified. If the other five events with lower
rates of extinction are considered major extinction events, then this one has to be.
Other evidence that supports my claim is that the reasons for the current extinctions
are due to humans, and the human population is continuing to grow.This pattern
tells me that the rate of extinction will continue to grow, making this a real event that
will last for a long time.

3. How might people be affected if the current rate of extinction continues into
the future?

If the current rate of extinction continues, people might be affected because the biodi-
versity we currently rely on for food and medicine may disappear. Once a species goes
extinct, it is gone forever, and we can’t benefit from it in the future.

4. (e&t quick check) Should we do anything to reduce the current rate of
extinction? Support your answer with evidence, and provide the trade-off(s) in
your decision. 323324

Sample response in favor of taking action: I think that we should do something to
reduce the rate of extinction. People benefit from biodiversity right now by getting food
and medicine from species.There are benefits in species that we haven’t even discov-
ered yet, and if we lose species, we lose all future potential from those species. But we
do need to use land to grow crops right now. So we may have to turn natural land
into farmland in order to grow enough food to feed people, even if that means losing
some species that live on the natural land. I just think we need to convert as little land
as possible and think of other ways to feed people.

Sample response against taking action: I don’t think we should do anything to
reduce the current rate of extinction. People need to use technology to grow food, get
energy, and build things. I think meeting those human needs will inevitably lead to
increases in the rate of extinctions, but I think it is more important to spend effort on
people than other species. I know we might lose some useful species, but food and other
resources are more important.

321 NGSPEA2
322 SEASAR1
323 NGCCNS4
324 SEASET1

206 EVOLUTION

THE SIXTH EXTINCTION? ACTIVITY 14

REVISIT THE GUIDING QUESTION

Is the current rate of extinction typical?

The current rate of extinction is approximately 10 times the background rate. This
is significantly higher than the five mass extinction events since the Precambrian
explosion 600 mya, so it is not typical.

EXTENSION

For students who are interested in exploring more about how the loss of biodiversity
might affect humans, have them explore websites that explain some of the ways
that humans benefit directly from biodiversity. See the SEPUP Third Edition
Evolution page of the SEPUP website at www.sepuplhs.org/middle/third-edition.

ACTIVITY RESOURCES

KEY VOCABULARY
extinction

BACKGROUND INFORMATION

THE SIXTH EXTINCTION

The sixth extinction is a popular name given to the current, ongoing extinction
event. Scientists also refer to it as the Holocene extinction or the Anthropocene
(human-caused) extinction. The widespread and large number of extinctions
includes all vertebrates as well as numerous families of plants and invertebrates.
Some entire habitats, and all the species they contain, are under threat of
extinction. These include coral reefs and rainforests. Scientists have calculated that
the current rate of extinctions is 100–1,000 times the background rate. E.O Wilson
calculated that at the current rate of human-caused extinctions, one-half of Earth’s
higher lifeforms will be extinct by the year 2100.

REFERENCES

Gerardo, C., Ehrlich, P. R., Barnosky, A. D., Garcia, A., Pringle, R. M., & Palmer,
T. M. (2015, June 19). Accelerated modern human-induced species losses: Entering
the sixth mass extinction. Science Advances, E1400253. doi: 10.1126/sciadv.1400253.

Mass extinctions. (n.d.). Retrieved from http://evolution.berkeley.edu/evolibrary/
article/massextinctions_01

Szabo, J., Khwaja, N., Garnett, S., & Butchart, S. H. M. (2012, October 8). Global
patterns and drivers of avian extinctions at the species and subspecies level. PLOS
ONE. 7, e47080. doi: 10.1371/journal.pone.0047080.

EVOLUTION  207

Name______________________________________________________________ Date____________

STUDENT SHEET 14.1

PAST EXTINCTION RATES

Extinction rate 20
(families per million years) 15
10
500 400 300 200 100 0
5 Millions of years ago
0600

LabAids SEPUP IAPS Evolution 3e
Figure: Evo3e TE 14_1
MyriadPro Reg 9.5/11

©2017 The Regents of the University of California

VISUAL AID 14.1 B

POSSIBLE EXTINCTION RATES OVER TIME

A

Extinction rate Extinction rate

Time Time
C D

©2017 The Regents of the University of California Extinction rate

Extinction rate Time Time
LabAids SEPUP IAPS Evolution 3e
Figure: Evo3e TE 14_2 VisualAid
MyriadPro Reg 9.5/11



15 Bacteria and Bugs: Evolution of Resistance
reading
1 class session

ACTIVITY OVERVIEW

NGSS CONNECTIONS

Students obtain information about four types of organisms that have evolved
resistance to chemical control methods. Students identify the cause-and-effect
relationship between human activity and the evolution of resistance to chemical
controls, and they consider whether this pattern is likely to continue in the
future. They conclude by using the principles of natural selection to explain the
phenomenon of the evolution of antibiotic resistance.

NGSS CORRELATIONS

Performance Expectations

Working towards MS-LS4-5: Gather and synthesize information about the
technologies that have changed the way humans influence the inheritance of
desired traits in organisms.

Applying MS-LS4-4: Construct an explanation based on evidence that describes
how genetic variations of traits in a population increase some individuals’
probability of surviving and reproducing in a specific environment.

Applying MS-LS4-6: Use mathematical representations to support explanations
of how natural selection may lead to increases and decreases to specific traits in
populations over time.

Disciplinary Core Ideas

MS-LS4.B Natural Selection: Natural selection leads to the predominance of
certain traits in a population, and the suppression of others. In artificial selection,
humans have the capacity to influence certain characteristics of organisms by
selective breeding. One can choose desired parental traits determined by genes,
which are then passed on to offspring.

MS-LS4.C Adaptation: Adaptation by natural selection acting over generations
is one important process by which species change over time in response to
changes in environmental conditions. Traits that support successful survival and

EVOLUTION  211

ACTIVITY 15  BACTERIA AND BUGS: EVOLUTION OF RESISTANCE

reproduction in the new environment become more common; those that do not
become less common. Thus, the distribution of traits in a population changes.

Science and Engineering Practices
Obtaining, Evaluating and Communicating Information: Gather, read, and synthesize
information from multiple appropriate sources and assess the credibility, accuracy,
and possible bias of each publication and methods used, and describe how they are
supported or not supported by evidence.
Constructing Explanations and Designing Solutions: Construct a scientific explanation
based on valid and reliable evidence obtained from sources (including the
students’ own experiments) and the assumption that theories and laws that
describe nature operate today as they did in the past and will continue to do so in
the future.

Crosscutting Concepts
Cause and Effect: Cause and effect relationships may be used to predict phenomena
in natural or designed systems.
Patterns: Patterns can be used to identify cause and effect relationships.

Common Core State Standards—ELA/Literacy
RST.6-8.1: Cite specific textual evidence to support analysis of science and
technical texts.
W.6-8.9: Draw evidence from literary or informational texts to support analysis,
reflection, and research.

WHAT STUDENTS DO
Students read about four types of organisms that cause problems for people, the
use of chemicals to control those organisms, and how the organisms ultimately
develop resistance to these chemicals. Students draw connections to the evolution
of antibiotic resistance introduced at the start of the unit.

MATERIALS AND ADVANCE PREPARATION

■■ For the teacher

1 Scoring Guide: constructing explanations (exp)

■■ For each student

1 Student Sheet 15.1, “Evolution of Resistance”
1 Scoring Guide: constructing explanations (exp) (optional)

212 EVOLUTION

BACTERIA AND BUGS: EVOLUTION OF RESISTANCE ACTIVITY 15

TEACHING SUMMARY

GET STARTED

1. Students are reacquainted with how humans can affect evolution by natural
selection.

a. Introduce this activity by connecting it to content learned in the earlier
activity “The Full Course.”

b. Have students read the introduction in their groups and brainstorm other
organisms that develop resistance to chemicals used by people.

DO THE ACTIVITY

2. Students read about four kinds of organisms that have developed resistance to
chemical controls used by people.325326327

a. Distribute Student Sheet 15.1, “Evolution of Resistance.”328

b. Instruct students to read the text using whatever strategy you have
selected.

BUILD UNDERSTANDING

3. Students respond to the Analysis.
a. Have a class discussion about Analysis item 1.
b. (exp assessment) Let students know they will be assessed on Analysis item 2.
c. Have a class discussion about Analysis item 3.

TEACHING STEPS

GET STARTED

1. Students are reacquainted with how humans can affect evolution by natural
selection.329

a. Introduce this activity by connecting it to content learned in the earlier
activity “The Full Course.”

Encourage students to look back in their science notebooks to refresh
their memories. Students will recall that when they forgot to take their
antibiotics as prescribed, any resistant bacteria that were in their bodies
were able to grow and reproduce. Eventually, nearly all of the bacteria
present in the population might be resistant to the antibiotic.

325 ELWH689
326 ELRS681
327 NGSPOE1
328 SELTDA1
329 NGLS4C1

EVOLUTION  213

ACTIVITY 15  BACTERIA AND BUGS: EVOLUTION OF RESISTANCE

b. Have students read the introduction in their groups and brainstorm other
organisms that develop resistance to chemicals used by people.

Have students briefly share out their ideas. Encourage students to share
any personal experiences, such as problems with mice or wasps that don’t
seem to be killed by pesticides. 330

DO THE ACTIVITY

2. (literacy) Students read about four kinds of organisms that have developed
resistance to chemical controls used by people.331332333334

a. Distribute Student Sheet 15.1, “Evolution of Resistance.”335

This activity is supported with a DART strategy in which students are
provided with activities that help them process the information in the
text. Use Student Sheet 15.1 to reinforce the changing effectiveness of
chemical controls. See Sample Student Response to Student Sheet 15.1 at
the end of this activity. For more information on DARTs, see the Literacy
section of Teacher Resources II, “Diverse Learners.”

Explain to students that they should fill out the table on the Student
Sheet after they read about each type of organism.

b. Instruct students to read the text using whatever strategy you have
selected.

You may choose to have students read the text independently, with their
partners, as a read aloud within groups, or as a whole class.You might
consider reading the passage out loud yourself because of some of the
challenging technical terms for the various chemicals.

BUILD UNDERSTANDING

3. Students respond to the Analysis.

a. Have a class discussion about Analysis item 1.

It should be apparent to students that resistance to chemical controls has
evolved many times and in many types of organisms, including microbes
(that cause diseases), animals, and plants. Ask students if any of the
organisms they might have mentioned at the start of the activity were in
the reading and to compare them to these examples.336

330 NGLS4B2
331 ELWH689
332 ELRS681
333 NGSPOE1
334 NGLS4B1
335 SELTDA1
336 NGCCCE1

214 EVOLUTION

BACTERIA AND BUGS: EVOLUTION OF RESISTANCE ACTIVITY 15

b. (exp assessment) Let students know they will be assessed on Analysis item 2.

This question requires them to apply their knowledge, gained throughout
the unit, about evolution by natural selection to the evolution of antibiotic
resistance.

Let students know that they will be scored using the exp Scoring Guide.
Project the guide or refer them to the guide they received in an earlier
activity as they construct their responses. 337338339

c. Have a class discussion about Analysis item 3.

Give students a brief time to think about the question regarding the inev-
itability of the evolution of resistance in their groups before having them
share out with the class. Ask students to justify their responses regardless
of how they respond.

SAMPLE RESPONSES TO ANALYSIS

1. When you compare all four examples, what similarities and differences do you
notice? 340341342

In all four examples, the populations of organism that people are trying to get rid of
using chemicals eventually became resistant to the chemicals.When newer chemicals
were then developed, the populations eventually became resistant to those chemicals as
well. Another similarity is that resistance didn’t take that long to develop—only about
20–30 years.The differences between the examples are that one of them, malaria, is a
disease, so the chemical is something people have to consume. Also, weeds don’t cause
or spread diseases to people.

2. (exp assessment) In the first activity, “The Full Course,” you explored why
it is important to finish an entire course of antibiotics even if you start to
feel better. Use information from this activity and what you now know about
evolution to provide a scientific explanation for why this is true. 343344345

337 SEASEX1 SAMPLE LEVEL-4 RESPONSE
338 NGSPCE1
339 NGCCPA1 When a person is infected with a disease-causing organism like bacteria, there is
340 NGCCPA1 variability among the individual bacteria because they have different genes that code
341 NGCCCE1 for different traits. Some of these genes make the bacteria very resistant to the chem-
342 NGLS4C1 ical substance that is in the antibiotic.When a person takes an antibiotic, the bacteria
343 SEASEX1 with genes that make them easily killed by the chemical are quickly eliminated from
344 NGSPCE1 the population.Those bacteria that have the resistant gene have a higher probability
345 NGLS4B2 of surviving and reproducing. But when a person forgets to take the antibiotic, the

EVOLUTION  215

ACTIVITY 15  BACTERIA AND BUGS: EVOLUTION OF RESISTANCE

very resistant bacteria survive and reproduce, and eventually there are too many
very resistant bacteria in the population for the antibiotic to get rid of. In our model,
there were still bacteria left at the end of the treatment, and nearly all of them were
very resistant.The antibiotic is no longer effective, and a new antibiotic to which the
bacteria are not resistant will be needed.This is an example of evolution by natural
selection. In this case, the presence of the antibiotic changes the environment and leads
to selection of resistant bacteria.
3. Can the evolution of resistance by pests or harmful organisms be avoided, or is
it inevitable?
It seems like it is inevitable. It has happened in so many different types of organisms
in so many places. And it seems like it doesn’t take very long to happen. In the cases
we read about, it seems like a chemical control is good for only 20–30 years before the
resistance evolves and a new control must be developed.
REVISIT THE GUIDING QUESTION
What is the evidence that resistance to chemical control methods is evolving in
other types of organisms?
Many types of organisms develop resistance. Students gathered evidence from four
types of organisms: mice, weeds, mosquitoes, and Plasmodium. All four of these
organisms developed resistance to the first chemicals that people used to eliminate
them. When people started using a new chemical, many of these organisms
developed a resistance to that chemical as well.

ACTIVITY RESOURCES

KEY VOCABULARY
evolution
natural selection
resistance

216 EVOLUTION

Name______________________________________________________________ Date____________

STUDENT SHEET 15.1

EVOLUTION OF RESISTANCE

Organism Problem caused Chemical control Effectiveness then Effectiveness now
House mice

Weeds

Mosquitoes

©2017 The Regents of the University of California Plasmodium

Name_______S__a_m___p_l_e__s_t_u_d__e_n__t_r_e__s_p_o__n_s_e___________________________ Date____________

STUDENT SHEET 15.1

EVOLUTION OF RESISTANCE

Organism Problem caused Chemical control Effectiveness then Effectiveness now
House mice Warfarin
Eat and soil human Effective for about 20 Not effective with
food, spread disease years , from 1970 until some mice now;
1990s some mice resistant
to super-warfarin

Weeds Compete with crops Glyphosate Effective for about 20 Over 30 species of
and other desirable years weeds now resistant
plants to glyphosate

Mosquitoes Spread disease Organophosphates, Effective until 1959 Resistant mosquitoes
pyrethroids in over 60 countries,
with some resistant to
two or more chemicals

©2017 The Regents of the University of California Plasmodium Causes malaria Chloroquine Effective for about 30 Resistant to
years until 1960s chloroquine and the
newer drugs that were
developed afterwards

16 Manipulating Genes
i n v e s t i g at i o n
2–3 class sessions

ACTIVITY OVERVIEW

NGSS CONNECTIONS

Students obtain and synthesize information from multiple sources about
technologies that people have used over time to change the traits of organisms to
make them more useful or desirable to people. They evaluate this information for
its accuracy, reliability, and bias. They consider the impact of this technology on
people and other organisms. The activity provides an opportunity to assess student
work related to Performance Expectation MS-LS4-5.

NGSS CORRELATIONS

Performance Expectations

MS-LS4-5: Gather and synthesize information about the technologies that have
changed the way humans influence the inheritance of desired traits in organisms.

Disciplinary Core Ideas

MS-LS4.B Natural Selection: Natural selection leads to the predominance of
certain traits in a population, and the suppression of others. In artificial selection,
humans have the capacity to influence certain characteristics of organisms by
selective breeding. One can choose desired parental traits determined by genes,
which are then passed on to offspring.

MS-LS4.D Biodiversity and Humans: Changes in biodiversity can influence
humans’ resources, such as food, energy, and medicines, as well as ecosystem
services that humans rely on—for example, water purification and recycling.

Science and Engineering Practices

Obtaining, Evaluating and Communicating Information:

Integrate qualitative scientific and technical information in written text with that
contained in media and visual displays to clarify claims and findings.

Gather, read, and synthesize information from multiple appropriate sources and
assess the credibility, accuracy, and possible bias of each publication and methods
used, and describe how they are supported or not supported by evidence.

EVOLUTION  219

ACTIVITY 16  MANIPULATING GENES

Crosscutting Concepts
Cause and Effect:
Cause and effect relationships may be used to predict phenomena in natural or
designed systems.
Phenomena may have more than one cause, and some cause and effect
relationships in systems can only be described using probability.
Connections to Engineering,Technology, and Applications of Science: Interdependence of
Science, Engineering, and Technology: Engineering advances have led to important
discoveries in virtually every field of science, and scientific discoveries have led to
the development of entire industries and engineered systems.
Connections to Nature of Science: Science Addresses Questions About the Natural and
MaterialWorld: Scientific knowledge can describe the consequences of actions but
does not necessarily prescribe the decisions that society takes.

Common Core State Standards—ELA/Literacy
WHST.6-8.2: Write informative/explanatory texts to examine a topic and convey
ideas, concepts, and information through the selection, organization, and analysis
of relevant content.
WHST.6-8.8: Gather relevant information from multiple print and digital sources,
using search terms effectively; assess the credibility and accuracy of each source;
quote or paraphrase the data and conclusions of others while avoiding plagiarism
and following a standard format for citation.

WHAT STUDENTS DO
Students search a collection of websites for information about one or more
technologies that people have developed to affect traits of organisms. They
summarize the key points from at least two sources and synthesize the information.
They evaluate each source according to a set of criteria. Students share the results
of their research with their peers. Finally, students consider the possible trade-offs
of using these technologies.

MATERIALS AND ADVANCE PREPARATION

■■ For the teacher

1 Scoring Guide: communicating concept and ideas (com)
1 Scoring Guide: evidence and trade-offs (e&t)

220 EVOLUTION

MANIPULATING GENES ACTIVITY 16

■■ For each pair of students

* 1 computer with Internet access
1 Student Sheet 16.1, “Manipulating Genes Research”

■■ For each student

1 Scoring Guide: communicating concept and ideas (com) (optional)
1 Scoring Guide: evidence and trade-offs (e&t) (optional)

If necessary, arrange for access to computers with Internet connectivity. Ideally,
students will work in pairs when searching for and reading the online references.

Determine how you will assign topics to each group of students. The goal of this
research is for students to learn about two ways that humans have manipulated
the genes of other organisms: through selective breeding programs and through
genetic engineering. A collection of age-appropriate resources is provided on the
student and teacher pages of the SEPUP Third Edition Evolution website at
www.sepuplhs.org/middle/third-edition, although you may wish to allow students to
search for additional references. Some of the references linked on the SEPUP
website are specifically about one or the other method, but some references
discuss both methods. Some references deal with one kind of organism (e.g.,
corn, chickens, dogs) while others have information about a variety of organisms.
Some references are more technical than others, involving a higher reading level.
Although allowing students choice as to which references to read is highly desir-
able, perusing the websites ahead of time may allow you to steer certain pairs or
groups towards a topic or reference(s) that will allow them to be most successful.

Also, determine how groups will share the results of their research with the rest of
the class. Possibilities include posters, slide presentations, oral presentations, and
postings on the class website.You will need to gather the materials and supplies
required for the presentation type you have selected.

TEACHING SUMMARY

GET STARTED

1. Students are introduced to human activities that have modified the genetic
makeup of various plants and animals.

a. Refer students to the photos in the Student Book introduction, and ask
them if they know anything about the ways people have selected and bred
desirable crops, pets (e.g., dogs and cats), or flowering plants they buy is
labeled as being either from genetically modified organisms (GMOs) or
GMO-free.

EVOLUTION  221

ACTIVITY 16  MANIPULATING GENES

b. Explain that students will investigate both traditional and modern
methods for modifying organisms.
Explain that they will gather information from resources, evaluate the
information, and communicate it though a presentation or display.

DO THE ACTIVITY

2. Students conduct online research about how humans have modified the genes
of other organisms.
a. Explain to students how the topic for their research will be determined.
b. Distribute at least one copy of Student Sheet 16.1, “Manipulating Genes
Research,” to each pair.
c. Explain to students that they will also evaluate the quality of the source of
information.
d. Discuss how to evaluate websites by directing students’ attention to
Appendix F, “Media Literacy,” in their Student Books.
e. Instruct students to begin their research, helping them navigate the
website or references as needed.
f. Let groups know how they should summarize their combined research to
share with the rest of the class.
g. Facilitate the sharing of information by all groups.

BUILD UNDERSTANDING

3. Direct students to the Analysis items.
a. Point out to students that Analysis item 1 emphasizes the crosscutting
concept of cause and effect.
b. (com assessment) Explain to students that they will be assessed on
Analysis item 2.
c. (e&t assessment) Point out to students that they will also be assessed on
Analysis item 3.

222 EVOLUTION

MANIPULATING GENES ACTIVITY 16

TEACHING STEPS

GET STARTED

1. Students are introduced to human activities that have modified the genetic
makeup of various plants and animals.346347

a. Refer students to the photos in the Student Book introduction, and ask
them if they know anything about the ways people have selected and bred
desirable crops, pets (e.g., dogs and cats), or flowering plants.

If they are not aware of this, explain that people have been selecting and
breeding organisms with desirable traits for thousands of years. Refer to
the examples in the photos, each of which has been modified by conven-
tional selective breeding techniques. In addition, most corn and some
salmon available today have been modified by modern genetic engi-
neering. Encourage students to pay attention when going to the grocery
store to see if any of the food they buy is labeled as being either from
genetically modified organisms (GMOs) or GMO-free.

b. Explain that students will investigate both traditional and modern
methods for modifying organisms.

Explain that they will gather information from resources, evaluate the
information, and communicate it though a presentation or display.348349

DO THE ACTIVITY

2. Students conduct online research about how humans have modified the genes
of other organisms.

a. Explain to students how the topic for their research will be determined.

If you have selected the topic for each group ahead of time, assign them
that topic. If you have decided to let students choose for themselves,
ensure that enough groups or pairs investigate each of the two methods:
selective breeding or genetic modification.

b. Distribute at least one copy of Student Sheet 16.1, “Manipulating Genes
Research,” to each pair.

346 NGLS4B2 If you decide to have pairs gather information from more than one refer-
347 NGCCCO1 ence, give them additional sheets as necessary. Review the questions in
348 NGSPOE2 the table on the top of the sheet, which is where students will record the
349 NGSPOE1 information they gather from the reference. Point out that students will
be identifying both the benefits and the possible negative effects of the
manipulation.

EVOLUTION  223

ACTIVITY 16  MANIPULATING GENES

350 ELWH682 c. Explain to students that they will also evaluate the quality of the source of
351 ELWH688 information.350351
352 NGCCCE1
353 NGCCCE2 Explain that the class will be gathering research from a variety of sources,
each of which is written for a specific purpose and audience. Being able to
224 EVOLUTION evaluate the quality and reliability of the source is essential for scientists.
Introduce the term “bias”. Explain that a biased statement might rely on
certain facts that support the author’s opinion while ignoring others that
don’t support the opinion. It might also rely only on measures of impact
or effect without making any comparisons, or it might rely only on opinion
without including any facts. The process of determining bias supports the
practice of obtaining, evaluating, and communicating information.

d. Discuss how to evaluate websites by directing students’ attention to
Appendix F, “Media Literacy,” in their Student Books.

If this is the first time that students have referred to this appendix,
consider having a class discussion about it.You might have students spend
time reading this in class or assign it for homework.

Review the questions in the table at the bottom of the Student Sheet,
which is where students will record information that will help them
evaluate the reference.

e. Instruct students to begin their research, helping them navigate the
website or references as needed.

To help students find appropriate information on the website or
reference, encourage them to do a search on key words, such as breeding,
modification, selection, genetic, etc.

Remind students to take notes as they gather information about their
topics. If they have any questions, they can record those in their science
notebooks to investigate, if time permits. When both pairs in a group are
finished, instruct them to share their results with one another.

f. Let groups know how they should summarize their combined research to
share with the rest of the class.

Possible ways of sharing their findings include posters, slide presentations,
oral presentations, or postings on the class website. Make clear to students
that they will be responsible for communicating their own findings to
others as well as gathering information from the other presentations.

g. Facilitate the sharing of information by all groups.352353

Encourage students to take notes in their science notebooks as they read
or listen to other presentations.You might model this for one or two of the
presentations by taking notes on the board or a poster.

MANIPULATING GENES ACTIVITY 16

Be sure to discuss both aspects of the research—the summary and the
evaluation. Because GMOs are the topic of much debate, students are
likely to conclude that a number of the references are written to persuade
rather than to simply inform.

Depending on the outcome of their research, students may mention
several reasons why GMOs are controversial, including potential impacts
on human health (e.g., the possibility of allergies) and biodiversity. Some
of these same controversies have also been applied to selectively bred
crops—relying on a reduced genetic pool may have consequences should a
disease wipe out that crop.

BUILD UNDERSTANDING

3. Direct students to the Analysis items.

a. Point out to students that Analysis item 1 emphasizes the crosscutting
concept of cause and effect.

Students may wish to refer back to the earlier activities “Mutations: Good
or Bad?” and “Mutations and Evolution” when answering this question.

b. (com assessment) Explain to students that they will be assessed on
Analysis item 2.354355

They will be assessed with the com Scoring Guide. Project the guide or
distribute copies to students, and review the scoring levels.

Analysis item 2 assesses Performance Expectation MS-LS4-5.

Review the levels and criteria in the Scoring Guide for integrating the
Disciplinary Core Idea of Artificial Selection and the Crosscutting
Concept of Cause and Effect with the Science and Engineering Practice
of Obtaining, Evaluating and Communicating Information.

c. (e&t assessment) Point out to students that they will also be assessed on
Analysis item 3.356

For this item, they will be assessed with the e&t Scoring Guide. Project
the guide or distribute copies to students, and review the scoring levels.

Point out that this question highlights the nature of science idea that while
science and engineering can describe the consequences of actions, it does
not necessarily prescribe the decisions that society takes. Those deci-
sions often involve politics, economics, ethics, and other considerations.
Consider having a class discussion about the question before students
write a response.

354 SEASCM1
355 NGPEL45
356 NGLS4D1

EVOLUTION  225

ACTIVITY 16  MANIPULATING GENES

SAMPLE RESPONSES TO ANALYSIS

1. How has understanding the cause-and-effect relationship between genes and
traits led to advanced methods of changing traits in organisms? 357358

Understanding that genes code for certain proteins that have a function has helped
scientists figure out how to get a desirable trait from one organism into another
organism.They know that if there is a change in the gene, this may cause a change in
the structure of protein and the function of that protein. Or if a gene with a desirable
trait from one organism can be introduced into another organism, it can allow an
entirely new function.This allows scientists to make changes to genes that have bene-
ficial consequences for people. For example, the gene for resistance to glycophosphate
can be taken from bacteria and inserted into crop plants to make them even more
resistant than weeds are.

2. (com assessment, MS-LS4-5) Compare and contrast the use of selective
breeding and genetic modification for manipulating the traits of other organ-
isms researched by the class. Be sure to include 359360361

a. how they are similar.

b. how they are different.

c. the advantages of each method.

SAMPLE LEVEL-4 RESPONSE

Both selective breeding and genetic modification are techniques for increasing
the frequency of traits, coded for by genes, that people consider desirable.They
are both used in a wide variety of organisms, including bacteria, plants, and
animals.They are different in that selective breeding can work on only the genes
that already exist in the organisms. In this way, it is like natural selection, but
it is called artificial selection because humans do it intentionally.The only way
to get variation for breeding is through variation from existing mutations. In
genetic modification, in contrast, humans can directly cause changes in a single
gene or small set of genes, even inserting genes from a completely different type
of organism into the organism being manipulated.The advantage of selective
breeding is that is doesn’t require any special equipment or outside knowledge.
Because changes happen relatively slowly—similarly to what happens with
natural selection—it might be less likely to cause negative consequences to people
or other organisms.The advantage of genetic modification is that there can be
more change since scientists don’t have to rely on existing variability, and the
gene can come from an entirely different organism that would never breed with
the organism to be modified. Change can also happen faster, since it doesn’t have
to rely on numerous generations.

357 NGCCCE1
358 NGCCCE2
359 NGPEL45
360 NGCCCO1
361 SEASCM1

226 EVOLUTION

MANIPULATING GENES ACTIVITY 16

3. (e&t assessment) Any method that changes the heritable traits in a population
has an effect on the evolution of that population. Do you think people should
intentionally manipulate evolution in this way? 362363364

SAMPLE LEVEL-4 RESPONSE

Sample response in favor of action: I think that people should use whatever
technology they have to make organisms more useful to people.We need to grow as much
food as possible to be able to feed the growing human population. Using both selective
breeding and genetic modification will allow us to do that.While there may be some
negatives, like it costing a lot of money to use these techniques, the money is worth it
because no one will go hungry. And if there are any harmful effects on other organisms
from these technologies, we can probably develop another technology to help them.
Sample response against action: I don’t think people should use these technologies,
at least not genetic modification.The possible consequences for humans and other
organisms are too big a risk just to grow more food more quickly.While there are
benefits to using these technologies, such as being able to come up with new varieties
of crops more quickly, the negatives are too great.We should find other ways to grow
more food, like developing other kinds of crops so that people have a greater variety
of food to eat.That way, some of the reasons for why we ever used these technologies
in the first place can be addressed a different way. For example, Roundup-ready corn
wouldn’t be needed if we used other methods to control weeds.

REVISIT THE GUIDING QUESTION

How have humans manipulated genes in other organisms?

Humans have been manipulating genes in other organisms for a very long time,
beginning with the domestication of crops. Advances in technology have now
allowed people to manipulate the genes of organisms directly through genetic
modification. This has been done in many different types of organisms.

EXTENSION

For students who are interested in exploring more about how humans are
manipulating genes through gene therapy, have them explore the websites that
explain how this is being done. Visit the SEPUP Third Edition Evolution page of the
SEPUP website at www.sepuplhs.org/middle/third-edition and go to the links for the
Manipulating Genes activity.

362 SEASET1
363 NGCCNS4
364 NGLS4D1

EVOLUTION  227

ACTIVITY 16  MANIPULATING GENES

ACTIVITY RESOURCES

KEY VOCABULARY
genetic modification
selective breeding
BACKGROUND INFORMATION

GENETICALLY MODIFIED ORGANISMS

Genetic engineering differs from selective breeding in that in the former, the
gene of interest is isolated from the cells of an organism, copied, and transferred
directly into the cells of another organism. The use of genetic modification might
reduce the time needed to transfer a specific gene for a desirable trait from one
variety to another. The first step in making genetically modified organisms is to
find the gene that codes for the desirable trait. This requires making a map of the
organism’s genes. Once the desired gene is located, biochemical techniques can
be used to cut the chromosomes into small pieces. The piece containing the right
gene is thereby isolated from the rest of the chromosome. Now the gene can
be copied. To make identical copies of a gene, scientists artificially insert it into
bacteria, and then allow the bacteria to make copies of the gene. The next major
step is to insert the copied gene into the cells of the organism being modified; this
is a more difficult process than getting the DNA into the bacteria. Once this is
accomplished, the organism is considered genetically modified.
Concerns have been raised over the use genetic modification. One concern
is that inserting a gene from one species into another may have unintended
consequences due to the change in the DNA sequence. Another concern is that
genetically modified organisms might breed with non-modified organisms, causing
unintentional spread of the modification into other organisms. If the modification
spreads in a population and is later found to be undesirable or dangerous, it could
be difficult to remove.

228 EVOLUTION

©2017 The Regents of the University of California Name______________________________________________________________ Date____________

STUDENT SHEET 16.1

MANIPULATING GENES RESEARCH

SUMMARY

Method(s) of
manipulation
Organism(s)

What need did it
meet or what problem
did it solve?
Benefits

Negative
effects
Other comments

EVALUATION

Who is the author?

What type of site is it (.gov,
.edu, .com, .org)?
Who is the intended audience?

What message does it send?

What is the purpose of the
reference (for example, to
inform, entertain, persuade)?



17 Evolution and Us
project
2 class sessions

ACTIVITY OVERVIEW

NGSS CONNECTIONS
Students synthesize their understanding of evolution by natural selection to
communicate to an audience of peers and community members one important
thing they have learned about how evolution has shaped and continues to shape
life on Earth.

NGSS CORRELATIONS

Performance Expectations
Applying MS-LS4-4: Construct an explanation based on evidence that describes
how genetic variations of traits in a population increase some individuals’
probability of surviving and reproducing in a specific environment.
Applying MS-LS4-6: Use mathematical representations to support explanations
of how natural selection may lead to increases and decreases to specific traits in
populations over time.
Applying MS-LS3-1: Develop and use a model to describe why structural changes
to genes (mutations) located on chromosomes may affect proteins and may result
in harmful, beneficial, or neutral effects to the structure and function of the
organism.

Disciplinary Core Ideas
MS-LS4.B Natural Selection: Natural selection leads to the predominance of
certain traits in a population, and the suppression of others.
MS-LS4.C Adaptation: Adaptation by natural selection acting over generations
is one important process by which species change over time in response to
changes in environmental conditions. Traits that support successful survival and
reproduction in the new environment become more common; those that do not
become less common. Thus, the distribution of traits in a population changes.

EVOLUTION  231

ACTIVITY 17  EVOLUTION AND US

MS-LS3.BVariation of Traits: In addition to variations that arise from sexual
reproduction, genetic information can be altered because of mutations. Though
rare, mutations may result in changes to the structure and function of proteins.
Some changes are beneficial, others harmful, and some neutral to the organism.
Science and Engineering Practices
Obtaining, Evaluating and Communicating Information:
Integrate qualitative scientific and technical information in written text with that
contained in media and visual displays to clarify claims and findings.
Gather, read, and synthesize information from multiple appropriate sources and
assess the credibility, accuracy, and possible bias of each publication and methods
used, and describe how they are supported or not supported by evidence.
Crosscutting Concepts
Cause and Effect:
Cause and effect relationships may be used to predict phenomena in natural or
designed systems.
Phenomena may have more than one cause, and some cause and effect
relationships in systems can only be described using probability.
Common Core State Standards—ELA/Literacy
WHST.6-8.2: Write informative/explanatory texts to examine and convey ideas,
concepts, and information through the selection, organization, and analysis of
relevant content.
WHAT STUDENTS DO
Students develop a presentation or visual display to help scientists convince the
public that learning about and understanding evolution is directly relevant to
people’s lives. They share this presentation or visual display within the classroom
(and may also share it outside of the classroom).

232 EVOLUTION

EVOLUTION AND US ACTIVITY 17

MATERIALS AND ADVANCE PREPARATION

■■ For the teacher

1 Scoring Guide: communicating concepts and ideas (com)

■■ For each group of four students

* supplies for creating presentations/visual displays

■■ For each student

1 Scoring Guide: communicating concepts and ideas (com) (optional)

* not supplied in kit

Gather supplies for presentations/visual displays. This may include chart paper,
markers, colored pencils, computers, and props for skits.

TEACHING SUMMARY

GET STARTED

1. Students consider the importance of communicating scientific ideas to the
general public.
a. Explain the importance of communicating science accurately and
effectively.
b. Explain the scenario for this activity.

DO THE ACTIVITY

2. Students create their presentations or visual displays.
a. Explain the requirements for the presentation or visual display by
directing students to the Procedure.
b. Explain that students will be assessed using the com Scoring Guide.
c. Circulate throughout the room as students work to answer questions.

BUILD UNDERSTANDING

3. (com assessment) Students share their presentations/visual displays with
the class.
a. Have students share their presentations/visual displays with classmates.
b. Have students share their presentations/visual displays outside of the
classroom (optional).

EVOLUTION  233

ACTIVITY 17  EVOLUTION AND US

TEACHING STEPS

GET STARTED

1. Students consider the importance of communicating scientific ideas to the
general public.

a. Explain the importance of communicating science accurately and
effectively.

Explain to students that making good decisions requires being as informed
as possible. Ask students to each think of a situation where this has been true
for them personally, and have them share the situation with their partners.

b. Explain the scenario for this activity.

Explain the following scenario: Students have been asked by a scientist
to help communicate the importance of understanding evolution by
natural selection to the general public. The scientist especially wants help
communicating to middle and high school students. They know that
you have been studying evolution in depth, and they are seeking your
help. They would like you to create a presentation or visual display to
communicate one of the most important things you have learned about
evolution that you think other students should know.”365366367368369370

DO THE ACTIVITY371

2. Students create their presentations or visual displays.

a. Explain the requirements for the presentation or visual display by
directing students to the Procedure.

While all presentations or visual displays must meet the criteria in
Procedure Step 2, the means by which students communicate may take
many forms. This activity is an opportunity for students to be creative and
use whatever medium will allow them to communicate most effectively
using the strengths and talents of all of the group members. Presentations
may be in many forms, including posters, blog posts, plays or skits, and
visual presentations using slides or animations.

b. Explain that students will be assessed using the com Scoring Guide.

Project the guide or refer students to the guide they received in a previous
activity.

c. Circulate throughout the room as students work to answer questions.

Probe them for how their presentation/visual displays satisfy the criteria
for the task.

365 NGLS4B1
366 NGLS4C1
367 NGCCCE2
368 NGSPOE2
369 NGSPOE2
370 ELWH682
371 NGCCCE1

234 EVOLUTION

EVOLUTION AND US ACTIVITY 17

BUILD UNDERSTANDING

3. (com assessment) Students share their presentations/visual displays with
the class. 372

a. Have students share their presentations/visual displays with classmates.

Consider having groups evaluate each other’s presentations/visual displays
using the com Scoring Guide.

Sample student responses are provided at the end of this activity in the
Teacher Online Portal.

b. Have students share their presentations/visual displays outside of the
classroom (optional).

You might consider having groups present to other classrooms in
the school, present to their parents or siblings, or even post their
presentations/visual displays on the school website.

SAMPLE RESPONSES TO ANALYSIS
1. Reflection: How have your ideas about evolution and its effects on people

changed during this unit?

Because this is a Reflection questions, answers will be unique to each students.
One sample response is shown here:

I did not realize that organisms are evolving all the time. For example, I didn’t
realize doctors and scientists are worried about bacteria evolving antibiotic resistance.
I also didn’t realize that there are other kinds of resistance evolving or that genetic
modification could change the evolution of other organisms.

REVISIT THE GUIDING QUESTION

How are humans affecting and affected by evolution?

Humans affect evolution because we interact with a wide variety of organisms that
may evolve in response to our actions. Humans also affect evolution by causing
extinction of organisms and by intentionally manipulating the evolution of some
organisms. We are affected by evolution because our actions can lead to changes in
the evolution of organisms that impact humans, from organisms that cause disease
to organisms we use for food and medicine.

This guiding question is the same as the last driving question. Revisit ideas
students have been generating and add to or revise as needed. You may also find
you want to return to the first driving question, "How do bacteria become resistant
to antibiotics?" and see if students have anything further to add.

372 SEASCM1

EVOLUTION  235



NGSS AND COMMON CORE

NGSS UNIT OVERVIEW

EVOLUTION

Performance Expectation MS-LS4-1: Analyze and interpret data for patterns in the fossil record that
document the existence, diversity, extinction, and change of life forms throughout the history of life on
Earth under the assumption that natural laws operate today as in the past.

Performance Expectation MS-LS4-2: Apply scientific ideas to construct an explanation for the
anatomical similarities and differences among modern organisms and between modern and fossil
organisms to infer evolutionary relationships.

Performance Expectation MS-LS4-3: Analyze displays of pictorial data to compare patterns of
similarities in the embryological development across multiple species to identify relationships not evident
in the fully formed anatomy.

Performance Expectation MS-LS4-4: Construct an explanation based on evidence that describes
how genetic variations of traits in a population increase some individuals’ probability of surviving and
reproducing in a specific environment.

Performance Expectation MS-LS4-5: Gather and synthesize information about the technologies that
have changed the way humans influence the inheritance of desired traits in organisms.

Performance Expectation MS-LS4-6: Use mathematical representations to support explanations of
how natural selection may lead to increases and decreases of specific traits in populations over time.

Performance Expectation MS-LS3-1: Develop and use a model to describe why structural changes to
genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or
neutral effects to the structure and function of the organism.

Activity Disciplinary Science Crosscutting Common
Description Core Ideas and Engineering Concepts Core State
Standards
Practices Mathematics:
6.SP.B.5
1. I nvestigation: The Full Course MS-LS4.B Analyzing and Patterns 6.RP.A.1
Students use a model to explore the MS-LS4.C Interpreting Data Cause and Effect ELA/Literacy:
cause-and-effect relationship between RST.6-8.3
inappropriate use of antibiotics and MS-LS4.B Developing and
the phenomenon of the evolution of MS-LS4.C Using Models Mathematics:
antibiotic resistance. As they use the MS-LS2.A 6.SP.B.5
model, students use mathematical rep- Using Math- 6.RP.A.1
resentations to support their analysis of ematics and ELA/Literacy:
patterns and trends in the results and to Computational RST.6-8.3
develop explanations for how and why Thinking
the population of bacteria is changing.
These explanations are based on the Analyzing and Cause and Effect
differential survival and reproduction of Interpreting Data Patterns
resistant bacteria when antibiotics are
present in their environment (the human Developing and
body they are infecting). Using Models

2. M odeling: Hiding in the Background Constructing
Students use a model to explain how a Explanations
change in the environment—a change and Designing
in predation—can cause changes in trait Solutions
frequency within a population of prey.
Students analyze and interpret data from
their model using mathematical repre-
sentations in their explanations.

Using Math-
ematics and
Computational
Thinking

EVOLUTION T-1

NGSS AND COMMON CORE

EVOLUTION (continued)

Activity Disciplinary Science Crosscutting Common
Core Ideas and Engineering Concepts Core State
Description MS-LS4.B Standards
MS-LS4.C Practices Cause and ELA/Literacy:
3. R ole Play: A Meeting of Minds MS-LS3.B Effect RST.6-8.2
Students develop an understanding of Constructing Patterns WHST.6-8.2
Darwin’s Theory of Natural Selection and MS-LS4.B Explanations
use it to explain why species change over MS-LS4.C and Designing Cause and Mathematics:
time. They learn why this explanation MS-LS2.A Solutions Effect 6.SP.B.5
has prevailed by listening to arguments MS-LS3.B Patterns 6.RP.A.1
supporting Darwin vs. Lamarck. They use MS-LS3.A Engaging in Structure and ELA/Literacy:
the theory to explain how a change in the Argument from Function RST.6-8.3
environment causes a change in trait fre- MS-LS4.B Evidence WHST.6-8.2
quency from one generation to the next. MS-LS3.A Structure and
MS-LS3.B Constructing Function Mathematics:
4. M odeling: Battling Beaks MS-LS4.C Explanations Cause and 6.RP.A.1
Students use a model to simulate the role and Designing Effect 6.SP.B.5
of genetic mutations in natural selection. Solutions Patterns ELA/Literacy:
They discover that mutations provide the SL.8.1
variation on which natural selection acts. Using Math- SL.8.4
Some mutations cause traits that have the ematics and
effect of enhancing an organism’s survival Computational
in its current environment. Students Thinking
explain that individuals possessing these
adaptive traits survive to have relatively Developing and
more offspring. Thus, these traits become Using Models
proportionally more common in the next
generation. This activity provides an op- Analyzing and
portunity to assess student work related Interpreting Data
to Performance Expectation MS-LS4-4.
Developing and
5. Modeling: Mutations: Good or Bad? Using Models
Students follow the inheritance of a
hemoglobin mutation through two Using Math-
generations. Students identify patterns ematics and
in their data and investigate the cause- Computational
and- effect relationship between environ- Thinking
mental conditions and the frequency of a
trait in a population. Based on their data Constructing
collection and analysis, students construct Explanations
explanations for how changes to a gene and Designing
influence an organism’s ability to survive Solutions
and reproduce. Specifically, students use
the example of hemoglobin to explain
how structural changes to genes, or muta-
tions, lead to changes in protein structure
and function, and how this can lead to
changes in the function of red blood cells,
which, in turn, can affect survival of in-
dividuals with the mutation. This activity
provides an opportunity to assess student
work related to Performance Expectation
MS-LS3-1.

T-2 EVOLUTION

NGSS AND COMMON CORE

EVOLUTION (continued)

Activity Disciplinary Science Crosscutting Common
Core Ideas and Engineering Concepts Core State
Description MS-LS4.C Standards
MS-LS4.B Practices Cause and Mathematics:
6. Computer Simulation: Mutations MS-LS3.A Using Math- Effect 6.RP.A.1
and Evolution MS-LS3.B ematics and Patterns 6.SP.B.5
Students continue investigating the inher- Computational Structure and ELA/Literacy:
itance and selection for the hemoglobin MS-LS4.A Thinking Function SL.8.1
mutation using a computer simulation. MS-LS3.B Constructing SL.8.4
Students use mathematical representa- MS-LS4.B Explanations Cause and
tions and analyze graphs to determine MS-LS4.C and Designing Effect Patterns ELA/Literacy:
the distribution of the mutation in their Solutions Connections RST.6-8.9
population over time. Students manip- MS-LS4.A to Nature of WHST.6-8.2
ulate different parameters to investigate Constructing Science: Science
multiple cause-and-effect relationships Explanations Is a Human ELA/Literacy:
between environmental conditions and and Designing Endeavor RST.6-8.7
natural selection in their population. This Solutions WHST.6-8.2
activity provides an opportunity to assess Patterns
student work related to Performance Constructing
Expectation MS-LS4-6. Explanations
and Designing
7. View and Reflect: Origins of Species Solutions
Students explore and explain how one Obtaining,
species of finch arriving on the Galapagos Evaluating, and
Islands 3 million years ago evolved into Communicating
the current 13 species. They also explore Information
how recent changes in the environment
have selected for different beak shapes
and sizes within a species, reinforcing
cause-and-effect relationships. Students
learn that evidence from the Galapagos
finches supports scientists’ assumptions
that the same processes that operated in
the past are operating today; thus, the
same cause-and-effect relationships hap-
pening in Galapagos finches today also
happened in the past.

8. Reading: History and Diversity
of Life
Students obtain information through
text and graphics about the history and
diversity of life. They learn how life forms
have evolved over time, with all organisms
sharing a common ancestor. They build
un their understanding of speciation and
evolutionary trees as a way to represent
evolutionary relationships, and they are
introduced to the process of extinction.

EVOLUTION T-3

NGSS AND COMMON CORE

EVOLUTION (continued)

Activity Disciplinary Science Crosscutting Common
Description Core Ideas and Engineering Concepts Core State
MS-LS4.A Standards
9. L aboratory: Fossil Evidence MS-ESS1.C Practices Patterns ELA/Literacy:
Students examine actual fossils of four RST.6-8.3
species representing a diversity of life MS-LS4.A Analyzing and Cause and Effect
forms that existed at different points in Interpreting Data ELA/Literacy:
the past. Then they examine simulated MS-LS4.A Connections to RST.6-8.3
stratigraphic data to detect patterns in the Constructing Nature of Sci-
fossil record. They analyze and interpret MS-LS4.A Explanations ence: Scientific Mathematics:
these patterns to place the four species in MS-ESS1.C and Designing Knowledge As- 6.SP.B.5
chronological order and, thus, determine Solutions sumes an Order ELA/Literacy:
their relative ages. and Consistency RST.6-8.7
Connections in Natural Sys-
10. I nvestigation: Fossilized Footprints to Nature of tems Mathematics:
Students look for patterns in a set of Science: Scientif- 6.SP.B.5
fossilized footprints, a kind of trace ic Knowledge Is Patterns ELA/Literacy:
fossil. They analyze the patterns to draw Based on Empir- RST.6-8.7
inferences about the organisms that left ical Evidence Cause and
these traces, including the behavior and Effect
size of the organisms. They argue for Analyzing and
the most plausible explanation for these Interpreting Data Connections to
patterns. Nature of Sci-
Engaging in ence: Scientific
11. I nvestigation: Family Histories Argument from Knowledge As-
Students analyze and interpret data to Evidence sumes an Order
look for patterns in the evolution and and Consisten-
extinction of families from three classes Connections cy in Natural
of vertebrates. They summarize how life to Nature of Systems
forms have evolved over time, assuming Science: Scientif-
that the same natural laws have always ic Knowledge Is Patterns
operated and will continue to operate in Based on Empir-
the future. This activity provides an op- ical Evidence Connections to
portunity to assess student work related Nature of Sci-
to Performance Expectation MS-LS4-1. Analyzing and ence: Scientific
Interpreting Data Knowledge As-
12. I nvestigation: A Whale of a Tale sumes an Order
Students compare anatomical structures Constructing and Consisten-
in modern adult whales and embryos Explanations cy in Natural
with fossil whales to construct an and Designing Systems
explanation about the evolutionary Solutions
history and relationships of whales. Patterns
The activity provides an opportunity Connections
to assess student work related to to Nature of Connections to
Performance Expectation MS-LS4-2. Science: Scientif- Nature of Sci-
ic Knowledge Is ence: Scientific
Based on Empir- Knowledge As-
ical Evidence sumes an Order
and Consisten-
Constructing cy in Natural
Explanations Systems
and Designing
Solutions

Analyzing and
Interpreting Data

Engaging in
Argument from
Evidence

T-4 EVOLUTION

NGSS AND COMMON CORE

EVOLUTION (continued)

Activity Disciplinary Science Crosscutting Common
Description Core Ideas and Engineering Concepts Core State
Standards
13. Investigation: Embryology MS-LS4.A Practices Patterns ELA/Literacy:
Students analyze and interpret skeletal RST.6-8.7
and embryological images to identify MS-LS4.A Analyzing and Structure and
patterns of similarities and differences MS-ESS3.C Interpreting Data Function ELA/Literacy:
across species that look very different MS-LS4.D RST.6-8.7
as mature animals. Students identi- MS-LS4.B Analyzing and Patterns WHST.6-8.9
fy patterns of similarities throughout Interpreting Data
developmental time to infer evolutionary Cause and ELA/Literacy:
relationships not obvious in the mature Engaging in Effect RST.6-8.1
animals. This activity provides an oppor- Argument from WHST.6-8.9
tunity to assess student work related to Evidence Connections to
Performance Expectation MS-LS4-3. Nature of Sci-
ence: Science
14. T alking it Over: The Sixth Knowledge As-
Extinction? sumes an Order
Students analyze and interpret patterns and Consisten-
of large-scale extinctions over the entire cy in Natural
history of Earth, and identify the five Systems
mass extinctions detected by scientists.
Students compare the possible causes of Connections
those extinctions, and learn that there to Nature of
may be multiple causes. They analyze Science: Sci-
data on the current rate of extinction ence Addresses
and engage in argument based on Questions
evidence about whether there is About the
currently a sixth mass extinction caused Natural and
by human activity. Material World

15. R eading: Bacteria and Bugs: MS-LS4.B Obtaining, Cause and
Evolution of Resistance MS-LS4.C Evaluating, and Effect
Students obtain information about four Communicating
types of organisms that have evolved Information Patterns
resistance to chemical control methods.
Students identify the cause-and- effect Constructing
relationship between human activity and Explanations
the evolution of resistance to chemical and Designing
controls, and they consider whether this Solutions
pattern is likely to continue in the future.
They conclude by using the principles of
natural selection to explain the phe-
nomenon of the evolution of antibiotic
resistance.

EVOLUTION T-5

NGSS AND COMMON CORE

EVOLUTION (continued)

Activity Disciplinary Science Crosscutting Common
Description Core Ideas and Engineering Concepts Core State
Standards
16. Investigation: Manipulating Genes MS-LS4.B Practices Cause and ELA/Literacy:
Students obtain and synthesize infor- MS-LS4.D Obtaining, Effect WHST.6-8.2
mation from multiple sources about Evaluating, and WHST.6-8.8
technologies that people have used over Communicating Connections to
time to change the traits of organisms to Information Engineering, ELA/Literacy:
make them more useful or desirable to Technology, and WHST.6-8.2
people. They evaluate this information Obtaining, Applications of
for its accuracy, reliability, and bias. They Evaluating, and Science: Inter-
consider the impact of this technology Communicating dependence of
on people and other organisms. The Information Science, En-
activity provides an opportunity to assess gineering, and
student work related to Performance Technology
Expectation MS-LS4-5.
Connections
17. Project: Superbugs and Other Ways MS-LS4.B to Nature of
Humans are Affecting Evolution MS-LS4.C Science: Sci-
Students synthesize their understanding MS-LS3.B ence Addresses
of evolution by natural selection to Questions
communicate to an audience of peers About the
and community members one important Natural and
thing they have learned about how Material World
evolution has shaped and continues to
shape life on Earth. Cause and
Effect

T-6 EVOLUTION

Phenomenon NGSS AND COMMON COREDrivingGuiding Questions ActivitiesPEStoryline/Flow
Questions (How an activity leads to
Some bacteria PHENOMENA, DRIVING QUESTIONS AND STORYLINE
have become subsequent activities)
very resistant to EVOLUTION
antibiotics. How do What happens when 1 [14, 15, MS-LS4-4 Some bacteria are more
This unit explores the anchoring phenomenon: Populations change over time. Some changes take placebacteriaa person does not16, 17]MS-LS4-6resistant to antibiotics than
Species look over very long time periods, while others take place over observable time periods. People can cause andbecometake antibiotics asothers, and because of that,
different today be affected by these changes. Examples include: there are more life forms now than there were in the past;resistant toprescribed? (Activity 1)can become more abundant
than they did a some kinds of organisms have gone extinct, like large dinosaurs; organisms that are harmful, like someantibiotics?over time.
long time ago. bacteria and pests, have developed resistance to our methods of eliminating them. Students generate and
answer questions such as: How have populations changed over time? What caused these changes? How areHow do speciesHow does the1, 2, 3, 4,MS-LS4-4Some traits increase an
people affected by and affecting evolution? Are people causing a mass extinction?change overenvironment affect5, 6MS-LS4-6individual’s chance of
time? an individual’s MS-LS3-1 survival in a specific type of
EVOLUTION T-7 probability of survival environment.
and successful
reproduction?
(Activity 2)

How does natural Natural selection is the process
selection happen? by which some traits become
(Activity 3) relatively more common in a
population over time.

What role does Variation in traits is caused
genetic variation by mutations, and mutations
play in the process are passed on to offspring;
of natural selection? the frequency of the trait in
(Activity 4) the population depends on
the environment.

How do mutations The sickle cell mutation is
affect survival? harmful when a person has
(Activity 5) two copies because it affects
the structure and function of
red blood cells; it is beneficial
when a person has one copy in
an environment with malaria.

Why does sickle cell The frequency of the sickle
trait frequency vary cell trait depends on two
across the world? environmental variables—the
(Activity 6) frequency of malaria and the
availability of health care.