AROUND 1.7 million years ago, our ancestors' tools went from basic rocks banged together to chipped hand axes. The strength and dexterity needed to make and use the latter quickly shaped our hands into what they are today – judging by a fossil that belongs to the oldest known anatomically modern hand....
Because the fossil is younger than the first tools, Ward's team believe it is the first evidence of anatomy evolving to suit a new technology. As stone tools became more widespread, those who had the wrist structure to use them would have had an evolutionary advantage over their weaker-wristed kin.
I find articles like this terribly misleading to the laymen, because they subtly promote the idea that the use of the tools caused the changes in the wrist. This is the old long-disproven Lamarckian theory. If you were to press the scientists on this, they would readily admit that, no, they're not saying that the tool use actually caused the changes, but that natural selection operated as a winnowing process, a sorting box -- the humans with the stronger wrists had better survival characteristics than humans with weaker wrists, and this produced more offspring.
This relies on several assumptions, some of which are statistically ludicrous, none of which are proven:
1. That minute variations in wrist strength had survival advantages that managed to cause statistical variations in excess of the normal hazards of prehistoric living (disease, accidents, predation, violence, starvation, etc.).
2. There was a wide range of genetic variance in wrist strength and structure from which to select, and
3. Random genetic mutations that materially and positively affected wrist strength fortunately appeared at exactly the time that early humans were expanding tool use.
The last one, especially, requires an incredible confluence of rare events.
Draw your own conclusions.
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