Can Darwinism Explain Aging and Lifespan?
Evolutionists struggle to explain
both reproductive longevity
and life longevity
— Why would natural selection eliminate the fittest? —
by Jerry Bergman, PhD
An article this month from the BBC with the title “How Darwinism is Changing Medicine” mentioned that evolutionists have failed to solve one major evolutionary problem: aging. It features one of the “founding fathers of evolutionary medicine,” Randolph Nesse.
Randolph Nesse was puzzled about why we grow old. He couldn’t wrap his head around why natural selection had not eliminated aging altogether. He spent months coming up with theories to explain it, but was unable to solve the riddle.[1]
Actually, Dr. Nesse has noted a real problem that still exists today. Living to a longer age means a longer reproductive period which normally would be selected for by evolution. This is because living longer allows the organism to have more offspring and more offspring would likely survive to reproduce. Consequently, the organism’s genes are more likely to be passed onto more offspring. If all other factors were equal, producing more offspring will confer on the organism a clear survival advantage.
George C. Williams, a leading evolutionist at Michigan State University, expressed the fecundity advantage for evolution this way:
natural selection will frequently maximize [fecundity] vigor in youth at the expense of vigor later on and thereby produce a declining vigor [senescence] during adult life. Selection, of course, will act to minimize the rate of this decline whenever possible. The rate of senescence shown by any species will reflect the balance between this direct adverse selection of senescence as an unfavorable character and the indirect favorable selection through the age-related bias in the selection of pleiotropic genes.[2]
In theory, natural selection would favor primarily those animals that 1) produce more offspring during their reproductive life, 2) have longer fertility periods, 3) and live longer, thus having more time and opportunity to reproduce more of their kind. These three factors all facilitate the events that fit the standard definition of “survival of the fittest.”
The number of offspring is critical in evolution. Assuming that most offspring survive long enough to reproduce, they contribute to the total species’ population size. Evolution would for this reason favor organisms that had a longer reproductive lifespan to produce more of its offspring, requiring a highly effective reproductive system.
A major result of the survival-of-the-fittest “force” would be the selection of the length of the reproduction period, an effect that Darwin called differential mortality, today often called differential reproduction. No selection advantage can exist in any living organism after it can no longer reproduce. Having a long reproductive cycle requires a comparatively long lifespan, and
by the ‘fittest’ Darwin meant the one with the largest surviving progeny…. In this sense rabbits are ‘fitter’ than lions, since they have been able to reproduce and occupy a larger area, in spite of man, than lions, which are fighting a losing battle against man.[3]
Furthermore, the number of mates is also a factor that has to be added into the equation. What actually determines “fitness” is not the number of mates, however, but rather the number of mates that successfully reproduce. Thus, evolution would select for both age longevity and reproductive longevity.
The one fact we are focusing on here is age longevity. “Aging is an Evolutionary Paradox,” said one paper: “…natural selection designs organisms for optimal survival and reproductive success” and predicts that longer and longer life would result.[4] It is a paradox of long standing:
For centuries, beginning with Aristotle, scientists and philosophers have struggled to resolve this enigma. The Roman poet and philosopher Lucretius, for example, argued in his De Rerum Natura (On the Nature of Things) that aging and death are beneficial because they make room for the next generation (Bailey 1947), a view that persisted among biologists well into the 20th century. The famous 19th century German biologist, August Weissmann, for instance, suggested – similar to Lucretius – that selection might favor the evolution of a death mechanism that ensures species survival by making space for more youthful, reproductively prolific individuals.[5]
Further research and an evaluation of this argument have shown this long-standing explanation has turned
out to be wrong. Since the cost of death to individuals likely exceeds the benefit to the group or species, and because long-lived individuals leave more offspring than short-lived individuals (given equivalent reproductive output), selection would not favor such a death mechanism.[6]
Simplistic Solutions
Randolph Nesse, in the report reviewed above, claims that he has finally solved the problem. But did he? His solution is that “aging is simply a side effect of the evolutionary pressure that has selected certain genes over others.”
In this proposed “just-so” solution Nesse provides no empirical evidence, including the gene or genes that he is referring to, or the clear advantage of this gene that offsets the clear advantage of the gene set that confers reproductive longevity.[7] Furthermore, as noted, reproductive longevity is positively related to age longevity: the “reproductive system is involved not only in propagation of the species but also regulates organismal metabolism and longevity.”
No evidence exists for the historical evolution of either life or reproductive longevity. This data are difficult to document, except to note that given the many thousands of years evolutionists claim that humans have been living on the Earth, individual humans do not live long. Evolutionists claim that Neanderthals have lived for over 400,000 years and yet no evidence exists for a gradual increase in their lifespan during this 400,000 years. Furthermore, evolutionists put modern human lineages and Neanderthals’ separation at least 500,000 to about 650,000 years ago. And “we know more facts about Neanderthals than any other extinct humans. Many thousands of their artifacts and fossils have been found, including several nearly complete skeletons.”[8] Assuming the evolutionary dating of 400,000 years, humans should have evolved to live much longer than the average 70 years as is true today.
The evolutionary dilemma was admitted in a printout from the London Natural History Museum: “scientists are currently uncertain whether the last common ancestor of Neanderthals and modern humans was Homo heidelbergensis, Homo antecessor or another species.”[9] The same observation exists for the animal world. Elk first evolved, accordingly to evolutionists, 25 million years ago, but only live on average for a mere 15 years.[10] Even if longevity increased only a few months per generation, after 25 million years elk should live for 200 years, as do the bowhead whales, which are also mammals.[11] Yet bowhead whales show few signs of age-related ailments that plague other animals, including humans.
From the creation worldview, life has not been on the earth long enough for longevity to have changed significantly.
Note the large range of lifespans. The lifespan is largely genetically controlled. From Wikimedia Commons.
Summary
If natural selection were assumed to be valid, it should increase reproductive longevity and life longevity. These are key biological traits that the theory would favor. All other things being equal, organisms with a longer span of time for reproduction—able to produce more offspring—would have a major survival advantage. The failure of this to occur is another example of the failure of evolutionary predictions. It also has implications for both reproductive and life longevity.
The creation explanation is that longevity is largely genetic and cannot be significantly lengthened by mutations as evolutionists teach, which is what is observed in the natural world. Mutations lower longevity by causing disease and damaging health, which is also what is clearly observed. According to the age lengths contained in the Bible, the average age of humans actually has declined significantly during the last 6,000 years.
References
Fig 1 Note the large range of lifespans. The lifespan is largely genetically controlled. From Wikimedia Commons.
[1] Quaglia, S. How Darwinism is changing medicine. BBC Future;
https://www.bbc.com/future/article/20230905-how-darwinism-is-changing-medicine, 6 September 2023.
[2] Williams, G. Pleiotropy, natural selection, and the evolution of senescence. Evolution 11:398-411, 1957.
[3] Solbrig, O.T. Evolution and Systematics. Macmillan Press, New York, NY, p. 9, 1966.
[4] Fabian, D., and T. Flatt. The evolution of aging. Nature Education Knowledge 3(3):9.
[5] Fabian and Flatt, 2011.
[6] Fabian and Flatt, 2011. .
[7] Antebi, A. Regulation of longevity by the reproductive system. Experimental Gerontology 48(7):596-602, July 2013.
[8] Hendry, L. Who were the Neanderthals? Natural History Museum; https://www.nhm.ac.uk/discover/who-were-the-neanderthals.html, 2023.
[9] Hendry, 2023.
[10] Geist, V. Deer of the World: Their Evolution, Behavior, and Ecology. Mechanicsburg, PA: Stackpole Books.1998. pp. 211–219.
[11] Morell, V. How some whales live more than 200 years. Science 2015. January 5 https://www.science.org/content/article/how-some-whales-live-more-200-years.
Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology for over 40 years at several colleges and universities including Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,300 publications in 12 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,800 college libraries in 27 countries. So far over 80,000 copies of the 60 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.