ISP Kirk Teacher Fellow Elizabeth Petersen on teaching evolution

This article appeared in the August 2013 (Volume 18 Number 3) issue of the Missouri Science News published by Science Teachers of Missouri (STOM), the state chapter of the National Science Teachers Association.

Why Teaching Evolution Is So Darn Fun

By Elizabeth Petersen
Science Teacher
Ladue Middle School, St. Louis, MO

I’ll never forget the first time a parent put her finger in my face and said “You better not be teaching about that evolution”. Wow. She was the mom of one of my top students. And, she was a doctor, too. I thought how on earth can I not teach about evolution? It’s only the biggest idea in biology that makes everything make sense. From that first finger in the face, I found ways to teach evolution that parents and students did not find threatening. I want to share these ideas with you.

First and one of the most important things you can do as a teacher is establish good relationships with your students and your parents. This is critical. If you know the students well you have a better chance of helping them, learn about evolution. The relationship sets the stage.

If you aren’t allowed to use the E word in your school– then go ahead and use Change over Time or natural selection or Adaptation. It still helps students understand the main concept and as teachers, our goal is to get all of our students to understand these important concepts. They are smart and might make the connection to the E-word later.

I have found a sequence that seems to help students learn the foundational ideas of evolution. In order for students to understand evolution, they first have to have a grasp of the nature of science. How do we know what we know? What is the difference between science and other disciplines? What qualifies as evidence? And, what essentially are the rules of science? Indiana University ENSI site has developed a site to help students understand the Nature of Science: http://www.indiana.edu/~ensiweb/natsc.fs.html

NATURE OF SCIENCE

I use the notion of CONPTT – In order to qualify as something as scientific, it has to meet the following criteria: The data as to be Consistent, Observable (either with eyes, or tools of science, like a microscope or telescope), Natural (as compared to supernatural), Predictable, Testable and Tentative. The students first have to learn what can qualify as science and what science isn’t. Since I am a big lover of angels, I always ask my students if I can teach them about angels in science class. The overall answer from the students is “No, Ms. Petersen, you cannot teach us about angels because it doesn’t meet the criteria of science. “ I will pout and stomp my feet and say, but I love angels. Angels are good. I don’t understand why I can’t teach about angels, and the students have to explain to me why angels aren’t considered scientific. They say maybe they are real, but they don’t fit the criteria of science. I ask them which one? And they often reply observable. Once they deny me the opportunity to teach about angels, they are hooked in understanding what can fit into science and what can’t. Students start to really understand the difference between beliefs and evidence. With beliefs, you don’t need evidence. With science, you do need evidence. And, this understanding about the difference between evidence and belief is key to learning about science for the rest of the year. They learn that science is not based on what is popular, but on what is based on evidence.

CubewordsA fun activity that I have the students do is the Mystery Cubes. From the book Teaching About Evolution and the Nature of Science. This is where you print out and make a cube with the word on the bottom covered over so students cannot see it. They then have to use observational reasoning and inferences to figure out what is on the bottom of the cube. This activity is really important because it helps students understand that science is based on observations and inferences.

Introducing Inquiry and the Nature of Science (Mystery Cubes)

Our unit on evolution is about 6 weeks, although evolution is a big idea that weaves throughout the entire year. We start out the Evolution unit with students learning about adaptations by giving each student a white butterfly and tell them to color them in order for the butterflies to be camouflaged, so that the butterflies can hide out in the open. Obviously this creates a lot of interest in how to hide a butterfly out in the open. Then students discuss why would a butterfly benefit from being hidden? This sets up the idea about how adaptations are structures or behaviors that help an organism survive. If you don’t survive, then, your genes don’t survive either. The big idea for students to understand is that the name of the game is Survival and Get Your Genes into the Next Generation.

After adaptations, students will learn about natural selection – how those organisms that are better adapted to the environment, survive and reproduce and those that aren’t better adapted, then don’t survive. These are concepts that students understand because they see it in their lives. I often use the analogy of a basketball tournament – which team gets to advance and which ones don’t – is really about natural selection. March Madness seems to come right at the time when we are learning about natural selection. How perfect. I have several activities that help students understand natural selection. One of the favorite activities that is online is found at http://www.techapps.net/interactives/pepperMoths.swf

Students get to come up to the SMART board and be the birds that get to “eat” the peppered moths. Check it out. You will love this web site. The students love this activity and understand that survival is key to getting your genes into the next generation.

From Natural Selection, the students then learn about fossils and deep geologic time. They learn how fossils are evidence of life that use to exist on the planet and how the evidence would show that life has been on the planet for 3.5 billion years. I often find fossils at antique stores or shows, or students bring them in. No matter how you get them, it’s always cool to watch a student’s face when they are holding something that is 65 million years old!!!

Next students learn about homologous structures, and comparative embryology. The following is an activity I have the students do with learning about comparative embryology. It’s from the NOVA site on pbs.org (http://www.pbs.org/wgbh/nova/education/activities/2317_odyultim.html). This activity will blow student’s minds in finding the similarity between the morphology of the different developmental stages.

Timing Is Everything NOVAactivity

MS. NATURAL SELECTION AND ADAPTATIONS

If you have read the Next Generation Science Standards (NGSS) then you can see that evolution is a major part of these new standards. For middle school these standards are titled MS. Natural Selection and Adaptations.

Students who demonstrate understanding can:

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. [Clarification Statement: Emphasis is on finding patterns of changes in the level of complexity of anatomical structures in organisms and the chronological order of fossil appearance in the rock layers.] [Assessment Boundary: Assessment does not include the names of individual species or geological eras in the fossil record.]

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. [Clarification Statement: Emphasis is on explanations of the evolutionary relationships among organisms in terms of similarity or differences of the gross appearance of anatomical structures.]

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. [Clarification Statement: Emphasis is on inferring general patterns of relatedness among embryos of different organisms by comparing the macroscopic appearance of diagrams or pictures.] [Assessment Boundary: Assessment of comparisons is limited to gross appearance of anatomical structures in embryological development.]

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. [Clarification Statement: Emphasis is on using simple probability statements and proportional reasoning to construct explanations

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. [Clarification Statement: Emphasis is on using mathematical models, probability statements, and proportional reasoning to support explanations of trends in changes to populations over time.] [Assessment Boundary: Assessment does not include Hardy Weinberg calculations.]

If you are familiar with the Page Keeley books on Uncovering Students Ideas in Science, then you will be happy to know that there are several Probes that fit into the Nature of Science & Evolution unit, too:

  • What is a hypothesis?
  • Is it a Theory?
  • Biological Evolution
  • Adaptation
  • Habitat Change
  • Is it “Fitter”?
  • Mountaintop Fossil

NSTA also has a document called The Position Paper on The Teaching of Evolution. You can download it from the www.nsta.org site as well.

There are many ways to support you in the teaching of evolution.

Please mark your calendar for Darwin Day 2014. Sean B. Carroll will be our guest speaker on Saturday, Feb. 8, 2014 at Washington University.

Just remember that your students deserve the very best. You can provide that by educating them about the biggest idea in biology and have a lot of fun too.