The Surprising Patterns of Health and Disease

The most exciting phrase to hear in science, the one that heralds new discoveries, is not “Eureka” but “That's funny…”

—Isaac Asimov (1920–1992)

When we see a new or unexpected pattern we often say, “That's funny…” Patterns give rise to scientific discovery; a break from an expected pattern or a newly recognized pattern demands to be explored, clarified, and understood. Connecting seemingly unrelated patterns can also lead to scientific discoveries. For example, a new area of medicine called “developmental origins of health and disease” studies how availability of resources can influence organ development and function. Studying organ development in one individual can also predict organ function in generations of descendants.

In this activity, students analyze five Task Cards, each with unique data sets to explore some of the same patterns that helped scientists first understand how organ development in the womb can affect a baby's health 50 years after birth. The activity uses data taken from actual research papers, with the exception of the pedigree charts and summative-assessment questions, which are a combination of real and imagined data. Although each task is meant to be self-explanatory, students will be more successful if they are familiar with line graphs, bar graphs or histograms, timelines, and pedigree charts. These are all explained in the lesson, but familiarity will speed up student analysis of the data.

This lesson has no prerequisite learning, so it can be used at the beginning of the year to introduce the scientific process, as it shows how real science evolves and gives students practice in reading charts and graphs. However, the Next Generation Science Standards (NGSS) disciplinary core idea it most obviously fits is MS-LS1.B: Growth and Development of Organisms (NGSS Lead States 2013). The lesson can also be used as an extension activity to a genetics unit, because it helps introduce a new field of genetics called epigenetics, which is shedding light on the nature-versus-nurture debate. Epigenetics explains how environmental stressors affect the behavior of genes. If you use this lesson as a genetics extension, you can wrap up the activity by explaining that environmental stressors experienced by the pregnant mothers, such as starvation or emotional stress, can cause the behavior of the baby's DNA to change, sometimes forever. Epigenetics is beyond the scope of this article but is clearly explained at the Genetic Science Learning Center and Let's Get Healthy! websites (see Resources).

Activity background

This activity takes approximately 55 minutes and can easily be adjusted by limiting the number of task groups. This is a jigsaw activity, where the class is divided into small groups called home groups because students will return to them at the end of the activity. Once students are familiar with their “home” group, you divide them into new groups called expert groups so they can analyze the pattern on their Task Card and become experts on their topic. Then, on your cue, students return to their “home” group to share what they have learned. The amount of time needed will depend on students' ability to transition from their expert group to their home group and on whether you use all five Task Cards. If you use all five tasks, the final discussion will require five students to report to the “home” group. If you use fewer Task cards, the “home” group discussion should be shorter. Also, your final wrap-up and assessment can be done the following day in 20 minutes.

The activity requires the following materials (all of which can be downloaded at www.nsta.org/middleschool/connections.aspx):

• The Discovery of Blood Type Through Patterns (done as an overhead presentation by teacher; alternatively, a copy can be given to each student);

• Dutch Hunger Overview (done as an overhead presentation by teacher);

• 5 different sets of Task Cards, A–E (each group of experts is assigned one task and each student in the group should have one Task Card that matches the card of everyone else in his or her “expert” group. Task Cards are worksheets specific to each of the five tasks. It is easier to keep track of the paperwork if each task is printed on different-colored paper. The Task Cards are not reusable as students will be writing on them; however, to save paper, the front of each task card can be printed and reused between class periods while the subsequent pages can be printed for each student to record observations);

• Task Card A (Dutch Hunger Pedigree Chart);

• Task Card B (Adult Heart-Disease Histogram);

• Task Card C (Calorie Intake of Dutch Hunger Line Graph);

• Task Card D (Heart Development Timeline [includes three Heart Research Cards]);

• Task Card E (Dutch Hunger Pregnancy Diagram);

• Task Card Keys (one for each group);

• Pattern Notes Summary Sheet (one per student); and

• Summative Assessment (one per student).

Small student groups (called “expert” groups) analyze a set of data from their respective Task Cards and write a synopsis of the patterns they discover. They will then switch to their “home” group and explain the data and their patterns to students who were in different expert groups.

Introducing the activity (5 minutes)

In order for this activity to be effective, begin by modeling pattern recognition. Explain to students that, just like doctors and scientists, they will be looking at graphs and diagrams to find patterns that will help them understand human health. Students are most interested when they understand that the data they will be seeing are authentic.

Project or hand out “The Discovery of Blood Type Through Patterns.” Begin the discussion by asking the following questions:

• When you look at the first graph, what patterns do you notice?

• What conclusions can you draw from this pattern?

• Do the other pictures show patterns that support this conclusion?

• Do the other pictures help you understand the first picture in a different way?

When scientists begin to see a series of patterns that all support the same conclusion, they can form a hypothesis that they can test by collecting more data and looking for more patterns.

The activity

Step 1 (10 minutes)

Divide your students into home groups of 10 students. Assign each home group an area and tell students they will be returning to report to this group once they have left to become an expert in one of the five patterns (tasks) the class will be studying. Explain that while they are in their “expert” group, they will study a Task Card and analyze its pattern; then each expert will return to his or her “home” group and explain this pattern. Taking good notes is very important, as students are going to have to teach their “home” group how to read the pattern and what it means.

Step 2 (20 minutes)

Organize students into their expert groups by having students count off by letters A through E. Two students in each home group should have the same letter. Allow students to join their fellow experts and begin studying their assigned Task Card. Group A should be given Task Card A, and so on. Students should have their own copy of the Task Card so they can take notes and take the card with them when they return to the home group.

Have students analyze their pattern as a group and answer the guiding questions on their respective Task Card (Figure 1). After they have written their Final Analysis, they should ask themselves as a group:

• Is what we are saying clear enough?

• Will it help the other students understand our data?

Figure 1. Students working in their “expert” groups.

Connecting to the Next Generation Science Standards (NGSS Lead States 2013).

Standard MS-LS1: From Molecules to Organisms: Structures and Processes http://nextgenscience.org/msls1-molecules-organisms-structures-processes
Performance Expectations The materials/lessons/activities outlined in this article are just one step toward reaching the performance expectation listed below. MS-LS1-5. Construct a scientific explanation based on evidence for how environmental and genetic factors influence the growth of organisms.
Dimension	Name or NGSS code/citation	Matching student task or question taken directly from the activity
Science and Engineering Practice	Analyzing and Interpreting Data	What did the patterns shown in the pedigree charts, histograms, and line graph tell you about the effects of the Dutch Hunger on babies developing during that time? According to the data, how many years later was this environmental stressor still affecting their health?
Disciplinary Core Ideas	LS1.A. Structure and Function In multicellular organisms the body is a system of multiple interacting sub-systems. These systems are groups of cells that work together to form tissues and organs that are specialized for particular body functions. LS1.B: Growth and Development of Organisms Genetic factors as well as local conditions affect the growth of the adult plant.	Each of our organs has critical “windows” during which they are most vulnerable to environmental effects that can cause them to develop incorrectly. Air pollution, smoking, stress, low oxygen, poor nutrition in the mother, and, of course, drugs and alcohol can all cause the baby's organs to develop poorly. On the basis of this information, how do you think a war might affect a country 50 years after it is over? What about a massive crop failure from global warming? Many scientists now believe that your DNA is affected by the environment you live in and the choices you make. How might environmental catastrophes affect the way species of animals change over time?
Crosscutting Concepts	Patterns	How was the pattern of heart development changed when environmental stressors intervened in the first trimester? In the third trimester?
	Cause and Effect	Open-ended prompts help students to make connections between resource availability during development and how these organs subsequently function later in life.

Note: Throughout these task cards, pregnancy duration is described as nine months to be consistent with what students find familiar, although we recognize that human gestation typically lasts 40 weeks (with the mother probably not knowing she is pregnant until after the first month). Fortunately, the original data work sufficiently well with a nine-month gestation without needing to be altered.

Give students the “Pattern Notes Summary Sheet” while they are in their expert groups. Have them record their inferences on the sheet and practice what they will say when they return to their home group. You may give the answer key to groups before they complete the summary sheet to be sure they are on the right track, if you wish.

Step 3 (10 minutes)

Convene the home groups after expert groups have agreed on and written the Final Analysis on the bottom of their Task Card sheet (Figure 2).

Figure 2. Sample student Final Analysis.

Have the experts take turns sharing their patterns and Final Analyses with their home group, with each student taking one minute to present his or her pattern. Remind students that it is their job to make sure their pattern is clearly understood by the home group and to listen carefully and take notes when the other experts explain their data. They should have answers from all five expert groups on their summary sheet.

Finally as a group, they should come up with a conclusion about the impact of nutrition and environmental stress on fetal development and human health and record it on their “Pattern Notes Summary Sheet.” They must support their conclusion with examples from each of the expert groups. They should examine their conclusion and ask, “Does it make connections between patterns? If not, which data do not make sense yet? Is there a missing piece of datum we would like to have?”

Wrap-up (10 minutes)

Depending on time, each group can share its findings and conclusions with the class, or the final analysis can be collected for an individual grade. Before conducting the summative assessment, there should be a classroom discussion that reviews the key points shown by the data. Look at the answer keys for the Task Cards and the Pattern Notes for the Final Analysis and use the discussion questions below to guide you. To increase student understanding of how patterns play a role in science, you could review a list of other famous scientific discoveries and the patterns that led to them (see discussion questions below).

Note: This activity focuses on the effects of a mother's starvation on the development of her baby's heart, though different organs have different critical developmental “windows” and, depending on how the environmental stressors line up with those windows, a baby's health may or may not be affected for life. Often the effects of poor organ development don't show up until later in life (see the Extension box on page XX for more about how stressors and genetics interact). Most students found the lesson interesting and were not bogged down when discussing pregnancy, conception, or birth in their student groups. The only concern that arose was from one student who was curious to know more about how to correct these effects. This is a great segue into social science discussions about topics such as the impact of war and global warming.

• What was the environmental stressor that affected babies being born in the Netherlands in 1945? (Famine.)

• According to the data, how many years later was this environmental stressor still affecting their health? (Fifty years, though it is still affecting grandchildren [see Extension on p. XX].) What was the health effect? (Heart disease.)

• What did the patterns shown in the pedigree charts, histogram, and line graph tell you about the effects of the Dutch Hunger on babies developing during that time? (They were at risk for heart disease.)

• Now think about the time line and the horizontal-line diagram. How was the pattern of heart development changed when environmental stressors intervened in the first trimester? (The damage to the heart was greater.) In the third trimester? (Because the heart was further along, the damage was not as great, so the baby was less likely to get heart disease later in life.)

• Each of our organs has critical “windows” during which they are most vulnerable to environmental effects that can cause them to develop incorrectly. Air pollution, smoking, stress, low oxygen, poor nutrition in the mother, and, of course, drugs and alcohol can all cause the baby's organs to develop poorly. On the basis of this information, how do you think a war might affect a country 50 years after it is over? What about a massive crop failure from global warming? (They should expect to see many people exhibiting heart problems 50 years after an extreme period of stress and hunger.) (formative assessment for MS-LS-5)

• If you were a doctor trying to figure out the influence of the environment on a baby's development, what other data would you like to see? What patterns would you look for?

• Can you think of other patterns that have led to important scientific discoveries? (Copernicus— solar system; Mendeleev—periodic table; Mendel—genetics; Darwin—natural selection; Wegner—plate tectonics.)

• Can you think of a famous scientific discovery that has not come from a study of patterns?

• Many scientists now believe that your DNA is affected by the environment you live in and the choices you make. How might environmental catastrophes affect the way species of animals change over time? (MS-LS4.C: Adaptation)

Assessment

Two summative assessment sheets contain two patterns previously unseen by students; one is displayed in a familiar line graph (easier) and the other is displayed in an unfamiliar table (harder) (Figure 3). Students are asked to analyze the data, answer questions, and make predictions based on their understanding of the patterns they see. Rubrics are provided for both, with examples of student work shown as well. You can download these materials with the online version of this article.

Figure 3. Sample student assessments.

Differentiation

Task Cards are ordered from easiest (A) to hardest (E), thereby allowing students of different levels to contribute in similar manners. Task C (“Adult Heart Disease Bar Graph”) can be turned into an advanced activity if the last question (labeled “Interesting Dilemma”) is answered, or it can be the simplest task if the last question is removed. The “Bees and Berries” summative assessment can also be used as part of an advanced activity.

Conclusion

This lesson can be used as a segue into many subjects. It can be used as an introduction to the scientific process to give students practice in interpreting scientific data, or it can help students understand how the growth and development of an organism is affected by its environment (MS-LS1) and how damage to that organism's development early on could cause it to have different traits as an adult (MS-LS3). Middle school is the perfect age to learn that our daily choices and immediate environment can affect our long-term health, as well as the health of our unborn children. As one student said as she read her Task Card, “I'm never going to get pregnant! It's too much responsibility!”

Extension: The amazing epigenetic discovery.

Patterns can not only lead to discovery, but also to prediction and action.

From what you have learned, what kinds of health issues might the grandchildren of the Dutch Hunger survivors expect? The data you have been working with today are real, and it turns out that scientists noticed the same patterns you did. They had one more of piece of datum that led them to the amazing discovery of epigenetics. The pattern they also noticed was that, even though the grandchildren of the Dutch Hunger survivors had plenty of food and were not alive during the famine, their health still showed signs of being influenced by the shock their grandmothers suffered. Yes, your DNA might be affected by things your parents and grandparents lived through!

Thanks to observed patterns, we now know that your DNA code may remain the same, but the way your DNA works can be affected by the environment. Epigenetics explains how DNA can be switched on and off by chemical tags that are formed during situations of environmental stress. A few of the environmental stresses that can affect the function of your DNA are air pollution (including smoking), poor diet, lack of nurturing, and stress. For more resources on this, visit the Genetic Science Learning Center or the interactive introduction to the topic from Let's Get Healthy! (see Resources).