Regatta:
As I have said before, the appearance of a limit to the population size of a sexually reproducing animal is to be expected. Anybody who didn’t expect it wasn’t thinking hard.
As we all know, extraordinary claims require extraordinary evidence. Well they require a lot of evidence, anyway. The limit on population size is NOT an extraordinary claim. Lack of such a limit would be an extraordinary claim. We didn’t live in cities until a very few thousand years ago. Who in the world ever thought it was going to be safe in the long run? THAT suggestion is what would require enormous amounts of evidence.
There are two lines of reasoning that lead one to expect the limit. Currently I shall review one, or rather part of one. I have said, “If selection is a race, then speciation is a race, too.” Check out the January 2015 summary if you want the rest of the logic. Just now I am going to consider tweaking that word “race.” After all the word is contaminated by overtones from another definition altogether.
Let’s consider using the word “regatta.”
Now there are many words for competition in different fields. A tennis contest is a “match.” A cricket contest is a “test match.” Runners and machines compete in “races.” Football teams and chess players compete in “games.” The word “regatta” does not simply mean a test for the fastest sailboat; that would be a “race.” It is traditionally a series of races.
Consider the race in selection. Suppose there is an environment with plenty of snakes lying about, and suppose there are a couple of kinds of flightless bird that might eat the snakes along with other things. The bird that is bigger with the longer neck can reach out farther to peck. Once it has taken the snake supply over the other bird can go specialize in running down lizards, perhaps. So in this simple case the fastest bird to a successful pecking range wins.
But the snakes might not take this lying down. (Sorry.) Some are venomous and will strike back. Some kind of snake develops the habit of sticking its tail up and shaking it. The cost to the snake is trivial; the cost to the bird is the chance it will attack the tail thinking it’s a head or at least the time it takes to make sure that there is no mistake.
Now when the bird takes a maximum performance lunch for lunch it must occasionally miss. Not getting the resistance of the strike on the snakes’ head it is in danger of flopping down right on top of the snake. This is called the bad way of making the girls laugh.
So the bird might, just by chance, develop an enormous fan shaped tail. If the bird is in danger of overbalancing forward the tail provides an effective brake with its air resistance. Now perchance the snake develops a way (over unthinkable eons of course) of keeping its skin when it sheds so that the skin piles up into a rattle. The rattle is bigger than the bare tail making it more conspicuous visually and audibly.
Now at the same time, the bird had been developing a pattern of huge eyes all over that big tail. Its real eyes are rather inconspicuous. The snake now has to devote some of its limited intellectual resources to ignoring the conspicuous eyes and dodging the head with the little real ones. So now the snake uses its rattle to get some echolocation on the bird. The bird responds by getting that tail to make the same sound as the snakes rattle.
Then somebody comes along and says, “The tail of the peacock is useless and costly to it proves to the peahen that the peacock is otherwise very fit.” Hmm. Maybe. But a lot of us are thinking that the snake is not the only one making heavy weather of it intellectually.
So this last series of events was an “arms race.” It is rather different from the straight head to head race for the longer neck. The moral is that, yes, selection is a race.
So imagine an environment with a new niche, like maybe snakes just moved in. They are new on the scene and are very successful as well as representing a possible food source. Things like this are going to be happening all the time; new niches will open and old ones close, maybe not so fast as it is now happening with humans stomping all over the global environment, but it happens.
A sailboat generally does not stand still. It may be aground, moored or docked, and if at anchor its movements are limited, but on a fair day with a fair wind when the anchor is atrip (If its “aweigh” it’s just clear of the bottom. “Atrip” means hosed down and lashed.) and sails are up, you are not likely to be able to pull up to the starting line of a sailboat race and wait for the gun. It’s probably going to take you some time to get to the starting line so the race may be truly begun.
So what we have in that environment is sort of a regatta. There are many selection races going on at once, and there are probably a number or races to speciation going on at the same time, too.
Maybe some day somebody will invent a race with several starting lines and several courses all going at the same time.
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