Ask Marilyn

Find solutions to Marilyn’s puzzles and this week’s Numbrix on the next page!

Are humans continuing to evolve in any noticeable way, such as having improved eyes or hearing, or hearts that function better?

—Sue Carlton, Arcadia, California

Humans continue to change over time, but not in the classic evolutionary sense in which a few random mutations are advantageous for survival; most have no impact on it, and a few are disadvantageous. In the long run, one may have expected the kind of change you mention. But this is no longer the case. The overarching reason is that culture has stepped between our species and its environment, so “survival of the fittest” has far less relevance than it once did.

Some say that only the advantages and disadvantages manifested during reproductive age make a difference. That is, the more fit individual is more likely to pass on his or her family genes, and the less fit is less likely. This thinking means if an individual thrives or suffers when he or she is older, it doesn’t matter in an evolutionary sense—the genes will have already been passed on (or not). Expansions on this kind of thinking abound.

My own thinking is that a more powerful force is at work. Human kindness is working to overcome nature, aiming for the survival of every human being, hence our effective and growing health-care systems. While this would seem to stifle evolutionary improvement, doing otherwise seems unthinkable.