What has Evolution Ever Done for Us?


This question often comes up in discussions with cdesign proponentsists

Darwin, and his contemporary, Wallace, proposed a theoretical mechanism by which the forms of organisms could change over generations, gainsaying the received wisdom of the time, which was the immutability of species - that species could not change, or - er - evolve. Prior to that, Georges Cuvier, the leading authority of the time, had maintained that all living forms were so exquisitely adapted to their environments, that change could not happen. The Darwinian/Wallacean mechanism wasn't very specific, to say the least, but it argued that if the offspring of any organism was not a perfect copy of it's progenitors, and if its variations were heritable, then those variations that assisted its further reproduction were likely to increase in frequency (representation) in subsequent generations, and this was a potential engine for change (evolution). In addition, the environment that organisms were adapted to was not fixed, but subject to change. Thus, life "tracked" changes in its environment.

Upon hearing of this, Thomas Henry Huxley, Darwin's close friend, declared, "How stupid not to have thought of that!"

Prior to that, one of the prominent hypotheses about how life could evolve was Lamarckism, whereby life, "striving" to survive and match its environment was the cause of change, famous examples of which were the offspring of giraffes inheriting longer necks because their ancestors had to strive to reach high branches, and the sons of blacksmiths inheriting large, powerful biceps because their fathers exercised theirs so vigorously. But no mechanism of inheritance could be identified;

The ultimate disaster of Lamarckism was when Trofim Lysenko took it up, in the Stalinist period, and it found favour as being uncontaminated by "capitalist" "Darwinian" influence, and this resulted in Lysenko's pseudoscientific ideas being applied to Soviet agriculture on a huge scale, with the subsequent mass starvation that ensued. Pseudoscience had killed millions.

But going back to Darwin and Wallace, they had a problem: They had identified that differential reproduction of variations could account for evolution, but they had no specific mechanism either. They both believed that "blending inheritance" must apply. This meant that, for example, red roses crossed with white ones would result in pink roses, or a banana plant yielding large bananas, crossed one producing small bananas would produce medium-sized bananas. How could variation emerge, if everything got averaged out?

Enter Gregor Mendel, an abbot who had conducted painstaking experiments and studies of inheritance, notably those of peas. He discovered that inheritance was quantized - digital - and that a roll of the dice determined what discrete characteristics could be inherited. 

Had Darwin ever discovered Mendel's work, evolutionary science would have advanced much faster than it did.

Still, even Mendel had no mechanism for inheritance either. People knew it was digital in nature, and had identified chromosomes made of DNA as the chemicals that must be involved, but it was not until the discovery of the exact structure of DNA by Franklin, Crick and Watson that it all became clear. (Franklin did not receive the Nobel Prise as Crick and Watson did, because it is not awarded posthumously. She had died too young of ovarian cancer). But this was a spectacular vindication of all the evolutionary scientists that had preceded them. It's hard to imagine how "intelligent design" speculations could have led to such an achievement.

Since the discovery of the structure of DNA, and RNA, the action of RNA polymerase and amino acid proteins, we have gone on to develop mRNA vaccines, identify and  correct genetic diseases and cancers using genetic interventions, and in general, understand in greater detail our place in the living world.

The speculations and fantasies of "intelligent designer" enthusiasts have contributed precisely nothing to any of this.

1 comment:

  1. The evidence demonstrates that humans can be intelligent designers.

    ReplyDelete