What's wrong with the "cicada theory" 1. The most common cicadas come out every year or every other year. 2. The 17-year cicadas (for example) don't come out once every 17 years -- they come out every single year. Just in different broods (groups differing by phase). Some broods are much bigger than others of course, and broods are often located in different parts of the country, but many broods can and do overlap. S…
That's a tautology. "A baby takes 9 months to be born because that's how long it takes to develop." Well, yes, but the question becomes, why does it take that amount of time to develop? Were there direct selection pressures acting on that length of time, or is that length of time mostly a function of other variables which are acted on directly by selection pressure?