{"id":26976,"date":"2009-08-26T08:19:56","date_gmt":"2009-08-26T08:19:56","guid":{"rendered":"http:\/\/scienceblogs.com\/gregladen\/2009\/08\/26\/natural-selection-is-survival\/"},"modified":"2009-08-26T08:19:56","modified_gmt":"2009-08-26T08:19:56","slug":"natural-selection-is-survival","status":"publish","type":"post","link":"https:\/\/gregladen.com\/blog\/2009\/08\/26\/natural-selection-is-survival\/","title":{"rendered":"Natural Selection is Survival Of the Fittest (A Falsehood)"},"content":{"rendered":"

Let me remind you of what we mean by “falsehood<\/a>.” A falsehood is not merely a statement that is factually untrue or logically flawed. Rather, it is a statement that when uttered in certain company rings true; It is a statement that sounds right to people; It is a statement that may be made frequently in reference to some body of knowledge, in this case, evolution or a related topic. But, the meaning that statement comes with is flawed. The statement is wrong in a way that requires explanation, and the explanation opens up the opportunity for new learning on the topic. So, the statement “humans evolved from apes” is a falsehood not because it is incorrect (in fact, it is<\/em> correct), but because the implications and meaning the statement comes with for most people are wrong. (Humans did<\/em> evolve from apes. Just not from those<\/em> apes, and we still are<\/em> apes!)<\/p>\n

So, what is wrong with the statement “Natural Selection is Survival of the Fittest”?
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\nWell, “Natural selection is..” should be followed by something that natural selection is, and this isn’t. Natural selection is a mechanism of evolution and by “evolution” we mean changes in gene frequency over generational time. So, with no reference whatsoever to genetics, this statement may be quite flawed. (I say what natural selection is at the end of this essay.)<\/p>\n

Survival<\/em> is a big word in this phrase, and is in fact a somewhat overwhelming word. “Natural selection is survival” is very misleading for two reasons. One is the word “survival” and the other is the word “is.” “… is survival” kinda implies that survival is the whole game, not just part of it. This seems to eliminate sexual selection from consideration. It is not (or, more exactly, not is….) survival, but rather, a number of things including survival. Furthermore, what we humans tend to mean by survival is longevity. Longevity is a trait that may be selected for. Longevity is a trait that may be selected against! In fact, shortevity may be what is selected for<\/em> in many cases. Life history parameters, including how long an organism lives, are features that are shaped by natural selection, not the basis for selection.<\/p>\n

Here’s what is really important here: We are a long lived species. Therefore, when we hear “survival of the fittest” we tend to combine our bias as a long lived species with the error of the Naturalistic Fallacy<\/a> and come up with a certain amount of comfort with that statement. But if you were a salmon (a sentient salmon, that is) you might be more comfortable with the statement “Natural selection is death in a stinking mud hole right after mating!”<\/p>\n

Natural selection is not survival, and natural selection is other important stuff that is not mentioned in the phrase. On top of that, the term “fittest” is strange. What the heck does that mean? Well, some people make the simple mistake that “fittest” means “buff” or “aerobically sound” or whatever. This is not, of course, what it means. But, understanding what it does<\/em> mean does not help the phrase “Natural selection is survival of the fittest” get less falsehoody. In fact, it may make it worse.<\/p>\n

The term “fitness” is used in evolutionary biology in relation to selection. A particular version of a genetic trait may have more or less fitness than an alternative version of that trait. So for instance, say there’s a gene that, in primates, codes for a protein essential for the implantation of a fertilized egg. Now, imagine a version of that gene that does not function at all. That would be a trait that has a different fitness than the ‘wild’ or ‘normal’ type. Specifically, it would have less fitness. Or, imagine that the run of the mill protein that helps with implantation works 90 percent of the time, but a new version comes along via mutation (by chance) that works 98 percent of the time. That version of the gene would potentially be selected for. It would have higher fitness.<\/p>\n

So fitness is linked to selection. Something being selected for is something with higher fitness. So, to say “Natural Selection is survival of the fittest” where “the fittest” means “more genetic fitness” is a false tautology. It is a tautology because it says “fitness equals fitness” and it is a false tautology because natural selection does not usually mean more fit. Usually, it means elimination of the not-as-fit. Most mutations lead to broken, not fitness-enhanced, genetic variance. So, really, “Natural selection is the elimination of less-fit alleles” is way, way more correct, but still only partially correct.<\/p>\n

Natural selection is a creative process that generates or shapes adaptations over evolutionary time. For a trait to be shaped by natural selection it must be genetic and heritable. For natural selection to affect a trait there must be genetic variation in the population in this trait. This variation must confer differential fitness. And, other things (random effects and selection working away on some other trait) must not swamp out the selection.<\/p>\n

“Natural selection is survival of the fittest” does not fit very well as a definition. It should be selected against. Naturally.<\/p>\n

More Falsehoods !!!<\/em><\/h3>\n

This post is one of a series on the topic of falsehoods. The following is a list of falsehoods posts in order:<\/p>\n