Is adaptation to an enviroment possible? Lets say you move a group of a hundred people out to an island thats made of broken glass. Assuming they died natural deaths, would their feet harden over the years? In other words, would they adapt to their surroundings and pass that on to their children?
Rather than adaptation in line with natural selection what you are suggesting sounds more like acclimatisation followed by Lamarckian inheritance.
If the initial population develop harder feet then they are acclimating to the broken glass environment. Their children will not be born with hard feet however and will themselves have to acclimate. What you propose is that the offspring would inherit the acclimated traits that their parents have acquired through living on the island, this inheritance of acquired characteristics is Lamarckian evolution and while there are a number of accepted situations where it does apply most evolutionary studies focus on heritable genetic variation as a result of mutation.
If the broken glass environment was dangerous enough that it caused those with softer feet to die then you might have a situation where natural selection would operate. In such a case those individuals with a genetic trait predispoing them to harder feet might live longer and have more opportunity to reproduce and have more children, consequently the proportion of children with genes providing tough soles would increase.
By specifying that the broken glass is not lethal and the people die natural deaths, although on an island of broken glass bleeding to death seems pretty natural, you are effectively removing any selective pressure and making your scenario one in which we would not expect natural selection to be operating on the trait you have in mind.
TTFN,
WK