Evolution and the Tree of Life Children’s Ideas

Children’s Ideas About Biological Evolution

Below are common ideas children in grades K-6 have about this topic, compiled from research on children’s ideas about science (see the Session 6 Children’s Ideas Bibliography). Consider what evidence might refute this idea, and why a child would be likely to believe this?

1. Change in environmental conditions directly causes evolution in the affected individuals.

In order for this idea to be substantiated, you would expect to observe entire populations changing during the same generation in response to a change in the environment. For example, if a plant population were subjected to drought conditions, someone holding this idea might predict that all of the individuals in the existing population would somehow change during their lifetime to become more drought-tolerant. Children may begin to understand evolution as a process that helps living things respond to environmental change so that they can survive. Children may reason that this has to happen during a lifetime — that something has to be changed immediately in the affected individuals. Thinking about evolution in this way may be challenged once children begin to understand evolution as a process that occurs at a population level over many generations.

2. Evolution “just happens.”

For evolution to be something that “just happens” suggests that there is no specific mechanism for evolution nor any predictable outcomes. Natural selection is overwhelmingly accepted by the scientific community as the process that best accounts for evolution. Evolution through natural selection predicts that, over time, populations will become better-suited to their environments. Many children in elementary school are likely to be acquainted with the term “evolution” before it becomes a part of their science learning. Some may understand it to be a process whereby life forms change, but without knowing how this occurs. They may think that the environment causes evolution, or that change “just happens.” Once children are introduced to natural selection, their ideas will develop further. Activities involving artificial selection may help children better understand natural selection. Examples of artificial selection are highlighted in the video for Session 5.

3. Species evolve because of a “grand plan.”

This is an idea that cannot be tested using scientific methods. There is no scientifically validated evidence of a “grand plan” for evolution, just the evidence that indicates that species do evolve. The idea that there is a “grand plan” for evolution is more a matter of one’s world view than a matter of science. Children may have religious or cultural backgrounds where this belief is held.

4. Evolution is goal-oriented; species evolving later in evolutionary time are “better.”

All species that exist on Earth today can be thought of as “success stories.” Scientists do not consider evolution to produce successively “better” species. Whether a species is a bacterium with a lineage that goes back billions of years or a human being whose lineage extends back only about 2 million years, each has evolved to be suited to its own environment at any given time. This “fit” is considered to be a consequence of evolution, not a goal, and given further environmental change, any species’ survival can be challenged. Children may have a hard time believing that a process has no goal. As they learn about evolution, the phrase “survival of the fittest” may promote this way of thinking. This idea may also be a product of modern culture, where human beings are often portrayed as the pinnacle of evolution.

5. Evolution happens over a few generations.

Historically, some of the best evidence for evolution (e.g., the fossil record) reveals that observable change in a species occurs over thousands or even millions of years. Many scientists would agree, however, that because natural selection acts during each generation, evolution is happening at some level throughout a species’ evolutionary history. There are also species that may evolve much more rapidly, under certain conditions. Nonetheless, scientists would agree that evolution takes longer than just a few generations to occur. In thinking about how long an event takes, it may be hard for children to comprehend time scales that extend more than a few generations — their own, their parents, and their grandparents, for example. The fossil record may be a good place to start to help children understand that the best evidence for evolution suggests that it takes a very long time — possibly hundreds, thousands, or even millions of generations — before change is observed.