Pollyanna VS Sod's Law

It's easy to see that predators (animals that kill and then eat other animals) are working for the downfall of their prey. But it's also true that prey are working for the downfall of their .fedators. They work hard to escape bei and it they all succeeded the predators would starve to death. The same thing holds between parasites and their hosts. It also holds between members of the same species, all of whom are actually or potentially competing with on another. If the living is easy, natural...

 Animals Can't Be Perfect in all Characteristics

We can expect bodies to be well equipped to survive, but this does not mean they should be perfect with respect to any one dimension. An antelope might run faster, and be more likely to escape a leopard, if its legs were a little longer. But a rival antelope with longer legs, although it might be better equipped to outsprint a predator, has to pay for its long legs in some other department of the body's economy. The materials needed to make the extra bone and muscle in the longer legs have to...

 Inter-Species Competition

A gazelle on the African savanna is trying not to be eaten by cheetahs, but it is also trying to outrun other gazelles when a cheetah attacks. What matters to the gazelle is being faster than other gazelles, not being faster than cheetahs. (There is an old story of a philosopher who runs when a bear charges him and his friend. "It's no good, you'll never outrun a bear," says the logical friend. "I don't have to." replies the philosopher. "I only have to outrun you.") In the same way, psycholo...