A game of Texas Hold'em
“Replay the tape a million times … and I doubt that anything like Homo sapiens would ever evolve again”– Stephen Jay Gould
One of the greatest evolution biologists, Stephen Jay Gould (1989) eloquently argued that evolution has no inherent direction. In other words, he adovocated the view that humanity (or any organism) is a cosmic accident, in his words, a “tiny twig on an improbable branch of a contingent limb on a fortunate tree”.
And it does seem so. After all, did mammals not displace millions of years of dinosaur dominance through a lucky meteor strike? Didn’t human beings emerge form ape-like ancestors by chance mutations?
Gould (1980) took his interpretation to fire an intellecutual shot at theists (people who believe in a God who is actively involved in the world), stating that a “sensible God” would not have used such a “odd” and “funny” process to create life.* Life evolved randomly, constrained by historical events, according to Gould.
Is evolution purely chance?
However, it has been suggested that Gould might overstated the chance aspect of evolution. Recent studies have shown that evolution is really more constrained (or more directed) than it really is.
Convergence
Morris (2003) has documented numerous examples of unrelated lineages acquiring similar biological traits. This phenonomen is known as convergent evolution. For instance consider the trait “bipedalism” (the ability to walk upright on two limbs). This ability is found in humans, kangaroos, birds and even dinosaurs, although all of them are distanly related (humans are more related to mice than kangaroos). Convergent evolution can even be seen in plants. Consider the two desert plant genera Euphorbia and Astrophytum. Although being distantly related, theyshare similar body plans.
What this suggests (with respect to Gould’s view) is that there appears to be a limited number of evolutionary solutions to remedy adaptive problems posed by earth’s ecosystems. In short, evolution seems to rely similar design features to fashion adaptive traits.
Epigenetics
Yet another field challenging the randomness of genetic inheritance is epigenetics. Epigenetics is the study of hertiable changes in gene expression due to mechanisms other than changes in DNA sequences. This field is challenging the traditional evolutionary ideas as it implies that environmental effects on the genes of parents can be passed down to the offspring (Francis, 2011).
One example common cited for this was seen in the offspring of the survivors of the Dutch Famine of 1944. Pregnant women who experienced the famine gave birth to children who were more vulnerable to diabetes, obesity and a number of health problems. In addition to that, it was shown that these health problems appeared to be inherited as the survivors’ offspring also had children who suffered the same diseases (Painter et al., 2009)
Conclusion
Although evolution is often portrayed as relying on purely chance events, recent studies have shown that evolution is more constrained that commonly understood. Of course none of what I have discussed showed that humanity was an inevitability– but it does show that the odds of a rational, self-aware being emerging on this earth is much higher than once entertained. This is food for thought for both the atheist, and the theist.
References
Francis, R.C. (2011) Epigenetics: The Ultimate Mystery of Inhertiance
Gould S.J. (1990) The Panda’s Thumb
Gould, S.J. (1989) A Wonderful Life
Hannam, J. (2011) God’s Philosophers
Morris, S.C. (2003) Life’s Solution
Painter, R.C., Osman, C., Gluckman, P., Hanson, M., Phillips, D.I.W., Rosebloom, T.J. (2008) Transgenerational effects of prenatal exposure to the Dutch famine on neonatal adiposity and health in later life. BJOG 115, 1243-1249.
*A short note on theology
Theologians have rarely argued that the existance of chance was a argument against or for God. In fact, they generally agreed human history was filled with chance events; evolution merely extended this theme (Hannam, 2011)
Tags: chance, evolution, That can't be true
