10 Misconceptions About Evolution

• Evolution is “only a theory”  - Nope. 

• “Survival of the fittest” means that evolution favors those who are “strongest”  - “Evolutionary fitness” refers to reproductive success; more precisely, it’s a measure of the success of genes in getting themselves projected into the future and is achieved in many ways—including the ability to obtain food, to avoid becoming food for someone else, to overcome diseases, to adjust to local weather and climate, attract mates, and so forth. In a pioneering research report, male European red deer who were smaller and who bore less impressively developed antlers were often more “fit” than the hulking males, because these “sneaky fuckers” (don’t blame me: This descriptive phrase is part of the technical literature) copulated with the females while the more massive bulls were busy fighting antlero-a-antlero with other more physically developed specimens.  

• Evolution explains the origin of life (or it’s supposed to) - Nope. That is primarily a job for biophysics, biochemistry, and geology. 

• Evolution acts for the good of the species - It is estimated that something like 99 percent of species that have existed are now extinct, so if evolution is working for the good of species, it has done a terrible job! What really argues against “good of the species,” however, is the actual way natural selection operates. Although it is possible that species sometimes compete, and, as a result, better adapted ones replace their poorly adapted alternatives, evolutionary competition takes place almost entirely within species, not between them. 

• Evolutionary theory says that living things are the result of chance - No, it doesn’t. There’s a half-truth hidden here; actually, less than half. Natural selection’s power comes from differential reproduction, the logical, unavoidable process whereby some genetic variants are more successful—more fit—than others. As such, its raw material comes from genetic diversity, which is produced by mutations and, in the case of sexually reproducing species, the reshuffling of genes via meiosis and sexual recombination. These processes are essentially random. But that’s just the source of the building blocks employed by natural selection. Natural selection definitely isn’t random—it does the heavy lifting and fitting together, by picking and choosing among various options, with some genes being projected into the future more than their alternatives—i.e., our old friend differential reproduction once again. Then the process happens over and over, repeatedly retaining those that are more fit and abandoning those that are less so. 

• Because we rely more and more on brain power and less and less on our muscles, human beings in the future will have big heads and small bodies - It is similarly easy to get hung up on the Lamarckian assumption that insects, crustaceans, fish, and amphibians that inhabit pitch dark caves are often blind because they stopped using their eyes, which therefore disappeared. Not so. These evolutionary changes, which are entirely compatible with Darwinian natural selection, occur because eyes are useless in the dark—hence, they lose the selective advantage that they convey in lighted environments—and, moreover, they take energy to produce while also being vulnerable to injury and infection. So, go ahead and exercise, use your brains, and hang out in dark places if you wish … but your offspring won’t have larger biceps, bigger heads, or smaller eyes as a result. 

• Gaps in the fossil record argue against evolution - Of course there are gaps in the fossil record! It’s remarkable that we have any such records at all, given how unlikely it is that any given dead critter will be fossilized and preserved, to which we must add an additional low probability that these remains will be discovered and recognized as such, perhaps hundreds of millions of years later. As for “missing links,” picture a line between two taxonomic groups, with as yet unidentified species connecting them; now, identify something between (linking) them: Now you have two new missing links! So, any time we find intermediate forms, there will necessarily be “missing links,” because every time a linking specimen is found (such as the discovery of Australopithecines linking nonhuman primates and Homo sapiens), new missing links are produced. In short, the more fossils, the more “missing links.” 

• Human beings aren’t evolving any more - We are. It’s just that evolution is typically a very slow process, limited by selective pressures (differences in the reproductive success of different traits and the genes that underlie them), along with generation times. It is possible that human beings in the future will have evolved the ability to function and reproduce readily with microplastics and “forever chemicals” in their blood, not to mention Strontium-90 in their bones and DDT in their fat, or maybe enhanced ability to manipulate computer screens, if such individuals have more kids. Each person’s genotype is fixed, so as individuals, we don’t evolve biologically. But Homo sapiens does, and will continue to do so, unless all people and their genes reproduce identically. 

• Because of evolution, living things are always getting “better” - Not necessarily. Early in the Earth’s history, a few billion years ago, life was very simple. Since then, it has evolved increasing complexity and enhanced ability to flourish in a variety of environments. In that sense, living things have gotten “better.” But any notion of improvement is subject to human-centered bias.  

• Evolutionary biology isn’t a science because it’s a historical phenomenon and can’t be tested - Many sciences, notably astronomy and geology, engage uniquely with historical phenomena (we can’t experimentally manipulate stars or continents), and yet they generate impressive empirical testing, often based on detailed observational regimes along with falsifiable predictions. And there is no question of their status as bona fide sciences. Evolutionary biology is no different.  

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