Why so Many Diverse Results from the Photoperiod Effect?

It may seem unlikely that there could be so many diverse consequences stemming from a single cause. Doesn't that go against the principle of simplicity in science, known as Occam's Razor? Actually, Occam's Razor tells us to look for only a few causes that explain many consequences, and that's precisely what the Photoperiod Effect alleges is happening. I've separately published a rather long essay about that venerable principle at logictutorial.com if you want to explore that topic in more depth. More to the point perhaps, in biological matters we generally expect our bodies to be well defended against both attacks and breakdowns, so why how could one change alter so much, and for so many people? The answer is that this is only likely if the change is one that we didn't frequently, or didn't ever, encounter in nature. Such changes often “unmask” otherwise benign genetic variation (for example, consider celiac disease.) Needless to say, years and decades of 16 or even 18 hour periods of daylight, or more, counting stray light in our bedrooms, were never encountered while humans and their ancestors evolved. There is more about this point, and other possible objections in a “Frequently Raised Objections” article that the PhotoperiodEffect.com index page points to.