To teach biology without explaining evolution deprives students of a powerful concept that brings great order and coherence to our understanding of life.

Teaching about Evolution and the Nature of Science, from the National Academy of Science, 1998

Our series on updating the Montessori Biology Curriculum has, up to now, addressed three important elements of biology: classification, phylogenetics (the Tree of Life), and adaptations. We covered updates from the field as they pertain to these areas, the importance of incorporating updates into our life science lessons, and practical suggestions and ideas on how to do so. In this final installment of our series, we address ideas related to teaching evolution concepts to children with Dr. Priscilla Spears.

Dr. Spears is a microbiologist who has been creating materials to support teachers with current science information since 1997. Over the past 24 years, she has also presented at local and national Montessori conferences, participated in teacher education programs, and consulted for other publishers of Montessori materials. Dr. Spears's mission is to support and enhance teachers' science literacy and, to that end, we welcome her ideas on evolution education—what teachers need to know to better help children understand this important and central topic of biology.

Cynthia Brunold-Conesa:

Can you give us a working definition of evolution so we're all starting with the same information?

Dr. Priscilla Spears:

I know that Montessori teachers give the etymology of new words during biology lessons, so let’s start with the meaning of the word. “Evolution” means the unrolling or unfolding of something. It comes from a Latin term for unrolling a scroll. In biology, evolution refers to the changes in Earth’s biota over time. Most of the time, we use the term “evolution” as shorthand for the process of evolution via natural selection. This idea was first formulated and promoted by Charles Darwin and Alfred Wallace in the mid-1800’s. The living world is not simple, and this idea is still being developed and refined.

Here is a simple expression of the idea. Evolution is the process by which life changes over time. It is also a change in the frequency of a gene within a population. By that, I mean that a gene becomes more common or rarer in a population of organisms. More simply, evolution is the result of random genetic variation, followed by selection via natural environmental conditions.

Cynthia:

Evolution is often referred to as “just a theory.” How should teachers help children understand what a scientific theory is, and why doesn't its status as a theory diminish the role of evolution for biologists?

Dr. Spears:

A scientific theory is not a guess or hypothesis, but our best explanation of data. Theories are not something scientists believe in. They find them to be useful in explaining the data and predicting future findings. Or they don't. Before scientists propose a theory, they gather data by observing and measuring. The observations and measurements have to be duplicated many times and in many places before a theory can be proposed.

Evolution is the best explanation we have for the data that have been collected about how life has changed through time. The fossil record is the main body of knowledge about these changes, along with the DNA of extant organisms, which holds a second record of life’s changes and relationships. If life developed from a common ancestor, we would expect all living things to share basic traits like DNA and cells. That is what we find, and it is what the theory of evolution predicted before the chemistry of the cell was known. Evolution also explains the diversity of life on Earth; if life continually experiments, we would expect new branches to arise, which is exactly what happens.

Cynthia:

Why do we need to teach evolution to young children?

Dr. Spears:

To quote biologist Theodosius Dobzhansky, “Nothing in biology makes sense except in the light of evolution.” We cannot honestly introduce the child to the living world without this concept. It is tied closely with current ideas about the diversity of life. Our timeline of life shows changes in life over time, and children need to know how this happens. Children also need to understand that evolution is a basic property of life. Life is not static; it never has been.

Cynthia:

What important ideas do teachers need to understand before they present evolution to children?

Dr. Spears:

Teachers need to know how evolution works. Genetic variations arise, and then natural selection acts. Traits that promote survival and reproduction are “selected”—more likely to be present in a population. It is very important to understand that natural selection acts via the current environment—the climate and the biota. Most of the time, natural selection maintains existing adaptations. When there is environmental change, different traits provide advantages for survival.

Natural selection favors two things—the ability to produce offspring and the ability to change. Any organism that cannot change is destined to become extinct because as the environment itself changes, new conditions arise and life must adapt.

The diversity of traits in a population is its library of solutions to life’s problems. This diversity is the key to long-term survival of a species. Processes that produce diversity increase a lineage’s chances of survival. Cross pollination in plants is an example of this. In animals, individuals that migrate from one population to another increase diversity. Sexual reproduction brings about a shuffling of genes during meiosis. It is a great driver of diversity.

It is also vital to understand that natural selection cannot see into the future, whether it is a changing climate or an invasive species. It doesn’t have a goal other than keeping life going. There are other factors in evolution, but these are the basics.

Cynthia:

What important ideas do children need to understand before we give them lessons on evolution?

Dr. Spears:

Before children can fully grasp evolution, they need to know certain concepts.

• Living things have basic needs.
• Organisms have traits that help them fulfill their needs in their environment. We call these adaptations.
• A specific environment provides for the needs of some organisms very well, and others less well. Some organisms are unable to live in one environment, but thrive in another.
• The offspring of living things are much like their parents, but there are always some variations.
• Organisms have more offspring than can survive, and there is a struggle for existence.

This last point is sometimes difficult for children to understand or accept. Teachers can access my archived newsletter “Elementary Darwin” for a helpful activity on calculating how many offspring an animal would have if none died and all reproduced for several generations.

Children really need to understand these fundamental concepts of biology before exploring ideas about natural selection.

Cynthia:

What are the major misconceptions about evolution that teachers should address in the classroom?

Dr. Spears:

It is very important for teachers to check for misconceptions and address them before moving forward with any science study. But correct information alone won’t erase inaccurate ideas. If teachers discuss these ideas with children, they can help them understand scientific, evidence-based concepts. Here are some common misunderstandings about evolution.

• Evolution is NOT only a march forward; evolution produces simpler as well as more complex organisms.
• Evolution is NOT working toward a goal. There is no such thing as an organism that is perfectly evolved for all time; there's good enough to survive and keep changing.
• Organisms do NOT evolve because they want or decide to do so; they evolve because some of their traits were advantageous to their survival.
• Extant organisms do NOT evolve from other extant organisms. People have asked, “If humans evolved from monkeys, then why do monkeys still exist?” Humans did not evolve from monkeys; many millions of years ago, before either of them existed, there was a primate ancestor that gave rise to them both.
• Individuals do NOT evolve. Natural selection acts on individuals, but it is populations that evolve. Remember, evolution is the change of a gene frequency in a population. A recent example from the news is the discovery of a population of elephants with a high proportion of tuskless members. In that case, the selective pressure was humans killing elephants for their tusks, which removed the genes for growing tusks from the population.

Cynthia:

Why do you think the topic of evolution is so emotionally charged?

Dr. Spears:

Evolution can be a challenge to teach because some people feel it is incompatible with their religious beliefs. They are comparing a belief system with a scientific theory, and these are two very different things. Both are important.

Cynthia:

How can teachers with religious beliefs reconcile this with teaching about evolution, and what do we say to parents who see evolution as a conflict with their family's belief system?

Dr. Spears:

I find the view that evolution and religion are in conflict to be very unfortunate. Rachel Carson said, “Believing as I do in evolution, I merely believe that it is the method by which God created, and is still creating, life on earth.” Whether or not a person can reconcile their religious beliefs and the theory of evolution, it is still important that children learn about the central organizing idea of biology. Even if a family rejects the theory of evolution, children need to know what they are rejecting.

Cynthia:

You've said elsewhere that teaching children accurate ideas about evolution might help alleviate racism and promote social justice. Can you expand on your thinking around this idea?

Dr. Spears:

One of the darkest chapters in the history of science has to do with the idea that life is always progressing and that humans are the pinnacle of creation. This false idea is usually illustrated with a white European male at the top of the ladder of life. It is an idea that was first promoted by white European scientists, after all. Under this ladder-of-life idea and with the misconception of improving the human race, colonial scientists committed atrocities against native Africans, and in the United States, immigrants of color were involuntarily sterilized during the eugenics movement.

If children learn that humans are a part of the tree of life, not the pinnacle of life, they are more likely to see all humans as equals. If children learn the value of diversity in the survival of life, they may find it easier to appreciate the variety of humans. If they see a timeline of humans that shows human civilizations from all continents and a range of cultures, they will have a more realistic view of human development. If their timeline of humans ends solely with light-skinned, blond people, children may get the idea that people who look like that are the only ones that count.

Recommended Resources

Priscilla recommends the following resources for teachers and students who want to learn more about evolution:

Websites for Teachers

• For an excellent tutorial on many aspects of evolution aimed at the adult general reader, see Understanding Evolution (UC Berkeley Museum of Paleontology)
• For more in-depth information about the ideas in this interview, see “Why Teach Evolution?” (Chapter 1 from Teaching About Evolution and the Nature of Science, The National Academy of Science, 1998)

Books for Children (that teachers will enjoy as well)

• Charlie and Kiwi: An Evolutionary Adventure, by Peter H. Reynolds and the New York Hall of Science (E1-E2)—A good starting place for evolution studies.
• Evolution: How We and All Living Things Came to Be, by Daniel Loxton (E2-MS)—Introduces evolution and addresses many misconceptions
• How the Dormacks Evolved Longer Backs and How the Piloses Evolved Skinny Noses, by Deborah Kelemen and the Child Cognition Lab (E1)—Fictional creatures show how natural selection works, helping children move beyond their preconceived ideas about real animals
• Moth: An Evolution Story, by Isabel Thomas and Daniel Egneus (E1)—The story of a moth population that shifted colors when the environment changed
• The Voyage of the Beetle, by Anne Weaver (E2-MS)—An engaging story with a talking beetle that accompanies Darwin on his voyage around the world and helps him figure out the “mystery of mysteries”—what causes the changes in living things

About the Author

Cynthia Brunold-Conesa, MEd, is an educator of adult learners at two AMS teacher education programs. She has 23 years experience as a lead guide at the Elementary and middle school levels. Cynthia also publishes on a variety of Montessori topics. She is AMS credentialed (Elementary I – II). Contact her at cynthia.conesa@meipn.org .

Interested in writing a guest post for our blog? Let us know!

The opinions expressed in Montessori Life are those of the authors and do not necessarily represent the position of AMS.