Teaching accurate evolution concepts is important for people and the planet November 08 2021, 0 Comments
I have been studying the concepts of evolution and false ideas about this process. “Evolution” literally means “unrolling,” and we use the word as a name for the changes in life over time. I am convinced that children (and everyone else) need to know valid ideas about evolution as a basis for social justice and peace.
The idea that some life is more advanced or important than other life started with Aristotle and Plato. They used an animal-vegetable-mineral classification, which is an intuitive idea that still exists. It leads to misconceptions about how evolution occurs and what it produces.
Aristotle introduced the “scala naturae” or great chain of being, which is a ranking of organisms from “lower” to “higher.” He ranked animals with blood above those without – the invertebrates whose blood he didn’t recognize. Plants, of course, went beneath animals, followed by minerals. Soil was at the very bottom of the scheme, which is the opposite of our current view. Now we see soil as a unique combination of living and non-living, and the foundation and sustainer of life on land.
During the Middle Ages, the idea of a chain or ladder of life became a religious idea as well. At the top sat the deity with the angels beneath, then humans, and so on down the ladder. Religious authorities presented this ordering as divinely given, which likely helped keep those on the lower rungs of social structure down there doing the hard work.
At one time, biologists used the great chain of being concept, and scholars thought that all organisms were striving to improve and move up the ladder of life. When Darwin proposed his theory of evolution via natural selection, he included the idea that there was no direction to evolution. After genetics and molecular biology showed the mechanism of evolution, most biologists accepted the idea that evolution doesn’t have a goal. Some biologists still thought that life was evolving toward complexity or some pinnacle of evolution.
One of the most famous – and wrong – illustrations of evolution shows a monkey, an ape, a caveman, and a modern man marching along from left to right. Note that I said “man” not “human.” This iconic illustration always ends with a Caucasian male. It leaves the impression that white males are the ultimate product of evolution.
There is no pinnacle of evolution, only a many-branched Tree of Life. There are no “highly evolved” organisms vs. more primitive ones. All life in existence is very complex; it has thousands of molecules in a highly ordered arrangement, all functioning together. All extant life has been evolving for the same amount of time although some lineages have undergone more visible changes than others. If life continues to exist, it continues to evolve.
It may seem that evolution produces more complex life, but that is not always the case except for the earliest life. Think of life starting as simple cells. There wasn’t any room to get simpler, but the opportunities to become more complex were plentiful. Even with that, there are many instances of a lineage of life becoming less complex and losing structures rather than developing new ones. This has happened frequently with parasitic organisms, but free-living animals also give up structures. The echinoderm lineage is sister to the chordates, which means that they shared a common ancestor. One branch got more complex and developed vertebrae; the other got simpler and combined several organ systems into a water vascular system. Both are highly successful.
As far as anyone can tell, evolution has no special direction and no goal other than the survival of life, all kinds of life. Especially all kinds of life because it takes diversity for life to continue. There is no climbing to the top, whatever that might be. With no ladder of life, there are no missing links, and paleontologists no longer use that term.
What does this mean in the classroom? The guiding adult must take great care to express the concepts of evolution accurately and to remove any diagrams that give false impressions.
I’ve written previously about the problem of teleology, the idea that organisms change because they want to or need to do so, but it is worth repeating. Fish didn’t decide to try growing legs, and they didn’t get them because they wanted to get out of the water. Those are teleological ideas. If an organism could change because it wanted to do so, there would likely be a lot of three-armed people taking care of small children. 😊
I don’t mean to say that people can’t change; they certainly change their minds and may work to bring about other changes in their lives. Individuals do not evolve, however. Evolution can be defined as a change in the frequency of a trait in a population. The process of natural selection brings about this change. A random mutation can change a trait in an individual organism, but evolution doesn’t take place unless that trait is passed to offspring, AND it confers an advantage for surviving and reproducing.
In the classroom, if children see a Tree of Life diagram that shows humans (or mammals) as a part of the diversity of life, they will have a better perspective than if they see a row of equally spaced boxes with humans/mammals at the far right. If they see a timeline of humans that shows modern humans with a range of skin colors, it will give a more accurate impression of what the evidence indicates has happened. An accurate timeline of humans cannot be a straight line. See https://humanorigins.si.edu/evidence/human-evolution-interactive-timeline for a more realistic view.
A timeline of humans that ends in light-skinned and light-haired people is not fair to anyone. I think it is best if children understand that there are many colors and cultures of humans, and that all of them are equally evolved and equally valuable. You may ask best for what? Best for our species and the whole biosphere.
“Life is a copiously branching bush, continually pruned by the grim reaper of extinction, not a ladder of predictable progress.”
― Stephen Jay Gould, Wonderful Life: The Burgess Shale and the Nature of History
Priscilla Spears, November 2021