In this lecture we examine these cases and expand our understanding of natural selection to accomodate these cases. It was known long before Darwin that many insects exhibit a high degree of social organization. For example, many species of termites, ants, bees and wasps form colonies composed of several hundreds of thousands if not millions of individuals. For example, consider the army ant Eciton burchelii . The evolutionary problem 1.
All ants live in societies and exhibit reproductive division of labor.
Ants evolved from solitary species that did not exhibit reproductive division of labor. At some point in the ancestral species that gave rise to ants, then, alleles that caused individuals to form societies and that caused workers to be sterile arose and were fixed by some process. 4. For Darwin, and many successors, it was hard to understand how that process could be natural selection. In particular, it was difficult to understand how sterile individuals could pass on alleles that rendered them sterile to the next generation, and this how the frequencies of those alleles could increase in a population. The phenomenon of Altruism 1.