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Daily Do

Why Is Cancer So Rare in Elephants?

Welcome to NSTA's Daily Do!

Teachers and families across the country are facing a new reality of providing opportunities for students to do science through distance and home learning. The Daily Do is one of the ways NSTA is supporting teachers and families with this endeavor. Each weekday, NSTA will share a sensemaking task teachers and families can use to engage their students in authentic, relevant science learning. We encourage families to make time for family science learning (science is a social process!) and are dedicated to helping students and their families find balance between learning science and the day-to-day responsibilities they have to stay healthy and safe.

Interested in learning about other ways NSTA is supporting teachers and families? Visit the NSTA homepage.

What is sensemaking?

Sensemaking is actively trying to figure out how the world works (science) or how to design solutions to problems (engineering). Students do science and engineering through the science and engineering practices. Engaging in these practices necessitates students be part of a learning community to be able to share ideas, evaluate competing ideas, give and receive critique, and reach consensus. Whether this community of learners is made up of classmates or family members, students and adults build and refine science and engineering knowledge together.

Introduction

Today's task, Why is cancer so rare in elephants?, creates an opportunity for students to look at examples of how the genetic makeup of elephants affect their ability to develop or not develop cancer. Students engage in science and engineering practices to figure out why genetics make elephants seemingly, immune to developing cancer.

This task has been designed in order to be used by students, parents, and teachers in distance and home learning. While students could complete this task independently, we encourage students to work virtually with peers or in the home with family members.

Elephant

Before you begin the task, you may want to access the accompanying Why is cancer so rare in elephants? slides.

Cancer Risk Among Different Species

Presentation of Phenomena (What am I exploring today?)

Cancer is a topic that is often covered in high school biology class when learning about cells. Often it is used at the end of a unit as an example of what happens when cells do not divide properly, or divide uncontrollably without regulatory mechanisms. As many, if not all, students are familiar with cancer in some way it is often a topic that is disused at a surface level of understanding. However, when used as a phenomena, it can allow for students to use cancer as a vehicle for understanding. For today's Daily Do, we use the table (pictured above) to prompt students to think about cancer differently than they have in the past.

Many traditional class discussions focus on cause, treatment and prevention of cancer. Today, we look at cancer from a new perspective - why some animals rarely get cancer. Although there are several animals that have a very low incidence of cancer, today, students will dig into figuring out Why is cancer so rare in elephants? What is going on with the elephants? Let's investigate!

Guidance: The goal is to get students thinking about why elephants and humans have such different rates of incidence of cancer. Presenting a phenomenon and asking students to generate questions about it creates a need to figure out the answer to those questions. This is authentic engagement and a powerful learning process (unlike "learning about" cancer as an example of what happens when cell division goes wrong).

Presenting the Phenomenon:

Have students observe the table on slide 2 and write down what they notice about the data presented. This is a critical step in eliciting further questions about why some organisms seem more susceptible to developing cancer and other organisms are not. Our goal here is to promote student thinking about questions they have related to this. ALL student questions are okay at this point. Our goal is to motivate curiosity and not distinguish between "good questions" and "bad questions" or "right questions" and "wrong questions". Common questions will arise for most students, which is what this task builds upon.

Investigative Questions (What questions do I have about what I just saw?)

Investigative questions are common questions kids may ask after they are introduced to the phenomena. Although questions may vary, many students are curious about what causes cancer and why it presents in so many different ways.

Guidance: It is important to allow time for thinking. Many students have ideas and questions but need time to formulate their idea or question into words. Some students may also benefit from writing things down first before they share. As adults we may be tempted to give them questions we feel might be important to explore, however we need to refrain from this and allow our students to practice asking their own questions. Our goal here is for students to consider all of the data they are seeing in the graph and to come up with questions around this data.

Common Questions: (slide 3)

  • Why do some humans have a risk of 90%?
  • What is LI Syndrome?
  • Why is the elephants risk so low?
  • Why wouldn't the elephants' risk be higher because they are bigger than other things listed, so they have more cells?
  • What is the TP53 gene?
  • Does having more of the TP53 gene give elephants a lower risk?
  • Why do dogs have a higher mortality rate than humans when they get cancer?
  • Do elephants have more TP53 genes because they are bigger?

We want to focus on one question in particular at this point: (slide 4)

  • Why do some humans have a risk of 90%?
  • What is LI Syndrome?
  • Why is the elephants risk so low?
  • Why wouldn't the elephants' risk be higher because they are bigger than other things listed, so they have more cells?
  • What is the TP53 gene?
  • Does having more of the TP53 gene give elephants a lower risk?
  • Why do dogs have a higher mortality rate than humans when they get cancer?
  • Do elephants have more TP53 genes because they are bigger?

Connection Guidance: Students may make connections to previous concepts in other grade levels. For example, students may mention that when cells divide wrong they can cause a tumor. They may also bring up ideas of how to 'kill' cancerous cells through a variety of different treatment options. We know that many students have been affected from cancer and want to ensure we are sensitive to their past experiences. It will be important that we acknowledge and validate what each students bring to the table but also move the discussion forward.

Narrowing the Scope

Now that we have identified the first question we want to figure out, it would be helpful to gain some additional background information about what you know about cancer and genes. Create a table like the one on slide 5 to illicit prior knowledge. Also, document any new questions and ideas for what we need to figure out next.

Discuss the ideas that surfaced from creating the table. We think there is a link between the TP53 gene and the risk of cancer, but we are not sure. From the data, we can see that elephants, dogs, and humans all have the gene but all present different rates of risks. We are not sure if elephants have more just because they are bigger but also notice that dogs and humans have the same amount. We need to find out more about elephants and this gene.

Gathering Information Investigation

We decided we need to know more about elephants and the TP53 gene. Have students watch the short video clip at the top of this news article (slide 7) about some research that has taken place to help us figure out if there is a relationship between the number of p53 genes an organisms has and their risk of cancer. As they watch, have students document important information and any new questions they have.

Could Elephants' 'Superhero' Cancer Gene Protect Humans Too?

Guidance: It is not necessary (during this activity) for students to figure out the intricacies of the p53 gene. The focus right now is not on the stricture and function of the p53, but instead on figuring out how investigating an organism with low risk of cancer could potentially help scientists figure out a way help prevent cancer in organisms that have a higher risk (like humans).

After student watch the video, have them use the printed section of the article to answer the questions on the student guide and document their ideas about how this research could potentially help humans.

This initial research also lead us to more questions: (Slide 8)

  • Are other animals at a low risk of developing cancer like elephants?
  • How can animals help with human treatments?
  • Are other animals being studied?
  • Why don't all cells react the same when subjected to stressors?
  • How can things than seem so similar react so different? Like why wouldn't all blood react the same?

Building Consensus

It is valuable for learners to stop periodically and gain consensus about what they currently understand to be true. Teachers do this often in the classroom, periodically pausing instruction to be sure students have achieved the learning milestones necessary in order to move forward.

Let's look back at what we've figured out up to this point:

After gathering information from the video, students will have figured out (slide 9):

  • p53 is a gene that 'guards our genome' this means it's job is to protect our cell
  • Elephants have many copies of this gene (40) and other animals have a lot less, like humans (2).
  • Some organisms only have one copy of the p53 gene (some humans) and are at a greater risk for developing cancer.
  • The p53 gene destroys mutated cells in the body so they can not reproduce.
  • Studying elephants could lead to helping humans that have cancer

Next, we revisit the questions we had after the first reading and decide what question(s) need to be figured out next? (Slide 10)

  • Are other animals at a low risk of developing cancer like elephants?
  • How can animals help with human treatments?
  • Are other animals being studied?
  • Why don't all cells react the same when subjected to stressors?
  • How can things than seem so similar react so different? Like why wouldn't all blood react the same?

We engage in a discussion and decide we need to figure out if there are other animals that present at low risk or are elephants the only ones. If there are other animals at low risk of developing cancer are they also being studied? We feel that these new questions warrant investigation so we engage in additional research.

Additional Investigative Research

We engage in additional research by reading an additional article to help us understand more about the relationship between the p53 gene and cancer risk. (Slide 11)

CNN Article: Elephants rarely get cancer. Here's why this matters to humans.

Washington Post Article: Rarity of cancer in elephants may help explain cancer in humans

Teacher Guidance: Both articles contain several points of the same information. However, the first article, from CNN, is a shorter and easier read and should be considered for students that may struggle with reading. If you are using this activity with students in a higher level class the Washington Post article is most appropriate.

EXTENSION: For students that are conceptually ready for a deeper dive into learning about how the p53 gene functions, also consider assigning: The p53 Gene and Cancer from HHMI Biointeractive. (Slide 12)

This tutorial from HHMI BioInteractive describes the structure and function of the p53 protein, how its activity is regulated in cells, and how mutant versions of p53 can lead to cancer.

The p53 Gene and Cancer

Building Consensus Continued...

We did some investigation through readings and discussion and discovered that:

  • Several other animals also have a very low incidence of cancer
  • The naked mole rat produces hyaluronic acid which helps kill mutated cells and they also have a gene, p16, which also helps prevent cancer cells from growing.
  • The bowhead whale can live up to 200 years (WOW) as a better ability to repair mutated cells.
  • Dogs, mice, and cheetah have a high risk of cancer
  • Many animals of both high and low risk are being studied in order to help figure out treatments for different cancers that affect humans.
  • Scientist hope that this research will lead to treatments including: gene therapy, genetic engineering or pharmacology

So, let's go back to our original questions:

  • Why do some humans have a risk of 90%?
  • What is LI Syndrome?
  • Why is the elephants risk so low?
  • Why wouldn't the elephants' risk be higher because they are bigger than other things listed, so they have more cells?
  • What is the TP53 gene?
  • Does having more of the TP53 gene give elephants a lower risk?
  • Why do dogs have a higher mortality rate than humans when they get cancer?
  • Do elephants have more TP53 genes because they are bigger?

Do we have enough information to create an argument from evidence for this question? What data have we gathered that we could use for evidence in defending a claim that either supports or refutes the idea that having more copies of the p53 gene gives an organisms a lower risk of developing cancer?

Teacher Guidance: At this point, students may want to engage in more research or you could have them engaged in a claim, evidence, reasoning activity. Traditionally, the CER activity is presented as a written task, however there are several ways for students to engage in a CER that allows for differentiation. Consider offering student choice, including; oral arguments, presentations, informational posters, or creating a public service announcement. For more information on other uses the CER see STEM Teaching Tool #17.

What did we figure out?

To answer our phenomena question Why is cancer so rare in elephants? we need to take a look back at all of the evidence we have gathered through our research: (slide 15)

Looking back, it didn't make sense that an animal that is so big and has so many cells developed cancer at such a low rate. We figured out:

  • Even though elephants live a long live and have a very large number of cells their rate of cancer is less than 5%
  • Many animals have a gene, p53, that helps guard against cancer. The p53 gene codes for a protein that regulates the cell cycle and apoptosis (cell death).
  • Humans have two copies of the p53 gene and some human only have one. Humans with one copy have a 90% risk of developing cancer.
  • Elephants have forty copies of the p53 gene.
  • Researchers are studying p53 in elephants to figure out how p53 might be used in human cancer treatments including; gene therapy, genetic engineering, and drug therapies.
  • Elephants are not the only animal that has a very low risk of developing cancer. Scientist are also studying axolotls, naked mole rats, blind mole rats, bats, and some whales.
  • Some of the animals being studied have other cancer fighting properties along with the p53 gene.
  • Scientist are also studying animals that have a high incidence of developing cancer including dogs and mice.

Based on what we have figured out and our current understanding about elephants and cancer, can we answer our phenomena question? Here, students have the opportunity to develop an explanation based on all of the connects they have made between cancer, genes, and elephants.

Connection Guidance: Almost everyone as been impacted by cancer in some way by the time they get to high school. As this can be a stressful topic for some students, be cautious when asking students to make personal connections about this topic.

NSTA Collection of Resources for Today's Daily Do

NSTA has created a Why is cancer so rare in elephants? resource collection to support teachers and families using this task. If you're an NSTA member, you can add this collection to your library by clicking ADD TO MY LIBRARY located near the top of the page (at right in the blue box).

Check Out Previous Daily Dos from NSTA

The NSTA Daily Do is an open educational resource (OER) and can be used by educators and families providing students distance and home science learning. Access the entire collection of NSTA Daily Dos.

Acknowledgement

This Daily Do is inspired by and uses materials from the The Disease storyline developed by the ISTA supported NGSS Biology Storyline Working Group and HHMI Biointeractive. These are an open-source resources that can be used by parents and teachers to implement student driven learning and can be found on the Illinois Science Teaching Association website.

Topics

Is Lesson Plan

Levels

High School

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