Expert: Dana Krempels, Ph.D. - 9/20/2011

Question
Hi Dana,

Thanks for providing this wonderful service.

Lately I have been thinking about evolutionary mechanisms and one thing that puzzles me is why all creatures seems to die. Yesterday I came up with a reasonable explanation that made some sense so I thought I would see if it maybe correlate with the "official" explanation. I have been googling the web hoping to find articles etc about the topic but without success and that's why I ask you. I hope that you might be able to answer the question or sketch out the essence of the most plausible explanations. I would appreciate if you linked to any articles/sites etc that deals with the topic.

In advance thanks

Answer
Dear Martin,

I don't think there's a consensus on or "official" explanation for an evolutionary reason for death.  People are more interested in how and why cells die than in determining what the historic reason for cell death is.  Some things just are, and there is no good way to explain them in terms of evolutionary fitness.

I suppose one might make the argument that in populations of related organisms, it is beneficial for older, less fecund individuals to die, leaving more resources for the younger, more fertile individuals that share the same genes.  (We want to avoid a group selection argument, and not invoke any sort of "altruism" that would be maladaptive for an individual.)

But that begs the question:  why do older organisms have reduced fertility?  It spirals inward and inward.

I'm curious to know what your idea is, if you're willing to share.

Dana