The Greatest Show from Darwin 10-Natural selection

10. Natural selection in the world ocean.

The guppy experiments left many questions. To answer these questions, let's ask how the situation is with the natural selection of fish in their natural habitat. How does the "self-evident" mechanism of excess offspring affect compared to how many of them will be able to feed in the world ocean.
Remember Richard Lenski's experiment, built on the principle of natural selection. The period with an excess of food was replaced by a period of hunger, which led to the inclusion of the mechanism of competition and selection of better adapted bacteria.

Outside the laboratory, the change of seasons leads to a change in the amount of resources needed to continue life. Everything is so and there is no arguing.
If we talk about human society, then the conviction that there are not enough resources haunts us all and everyone individually from birth. Money, concert tickets, groceries in the fridge and bottles of beer on the table have an unpleasant tendency to run out. The imminent depletion of energy resources, fresh water, and fertile lands is a constant topic of news, periodically warmed up by the media with renewed vigor.

For at least the last half century, we have been informed that the proven reserves of raw materials will last for a maximum of 50-100 years. So it was in the 70s of the twentieth century and at the beginning of the two thousandth. The situation has not changed now. Resources run out all the time and invariably run out after a magical 50-100 years.

Of course, the fact that more and more new deposits are being found does not negate the fact that resources cannot be unlimited. However, this knowledge does not kill most of the population. Keeps in some tension, as well as the fact that the salary is about to end. And that's all.

But this is in human society. And in the animal world, according to the general idea, there are constantly not enough resources, which leads to the extinction of insufficiently evolved ones. Ideally, as presented by bacteriologist Richard Lenski in an experiment on E. coli, such extinction should occur regularly, i.e. every generation.

How often does extinction actually occur in the natural environment? Or, at least, how much the lack of food affects the evolutionary processes.
Let's finally take a look into the depths of the world ocean. To the place where life originated many millions of years ago and triumphantly came to land, continuing to evolve in a competitive struggle to this day.

Let's look into any encyclopedia where it says that the main producers of organic substances in the aquatic environment are algae. "Algae directly or indirectly serve as a food source for all aquatic animals." In addition, they serve as a home for many species of fish.

The fact that fish can eat their homes in the struggle for survival should not cause us much doubt. After all, in a competitive struggle, the inhabitants of the oceans are obliged to periodically (preferably every year) eat out all the aquatic algae in order to implement natural selection.

Let's go back to the encyclopedia. Algae are the most numerous, the most important for the planet and the most widespread photosynthetic organisms. They are the main source of oxygen on the planet. According to various scientists, algae synthesize from fifty to eighty percent of the oxygen needed every second by all living organisms from the most inconspicuous guppy to you and me beloved.
Are you having trouble breathing? Maybe you periodically experience a lack of oxygen?

No? How is it? After all, natural selection requires that main source of oxygen periodically (prefeably always) be close to complete exhaustion.
You and I have just imagined the scene of fish eating their homes. Now we need to imagine how the same fish, dying from lack of oxygen, are struggling with their last strength for the last algae.

Didn't work out? I agree, in order to imagine such a thing, you need a very rich imagination. Even more imagination should be possessed by someone who wants to convince himself that it is possible to compete for what is in excess.
To start such a competition, the inhabitants of the seas would need someone who could convince them that the resource they need is limited and will end very soon (say, in 50 years).

However, then it will be necessary to recognize that pisces have a complex mental organization and are able to experience fear about what will happen to their children in the distant future.
Jokes aside. It turns out that it is not the Siberian taiga and the Amazon rainforests that are the lungs of the planet, but the world ocean. It accounts for up to eighty percent of oxygen synthesis, and all other sources, including the taiga and the Amazon, account for only twenty percent or a little more.
How much can the reduction of algae, say, by half, affect the oxygen level? It is unlikely that this could have gone unnoticed? But what about survival, then?
Apparently, locally - somewhere in closed reservoirs, the depletion of these important food resources is possible. Even in some local areas of the world ocean, nutritious algae can theoretically disappear completely without a particularly noticeable effect on the oxygen balance of the planet. But knowing, thanks to the excellent television broadcasts of the Discovery and Animal Planet channels about the grandiose range of the migration routes of whales, sharks, dolphins and schools of smaller fish, we can not worry that such events are at least some serious obstacle to a good diet of fishes.

It's too early to worry about natural selection. Sexual selection and predators are still in stock. And even though we all remember the phrase about wolves – forest attendants from childhood, but in the world ocean predatory fish hunt not for the sick, but exclusively for those who have not had time to evolve. Exactly. After all, in conditions of abundance of food resources, all individuals have the same right to procreation, the selecting agent can only be the irrepressible appetites of predators.

On this optimistic note, I was going to put an end to it, but after taking another look at the description of Richard Lenski's experiment with E. coli, I have to postpone it.
Lenski's brilliant hint is in the results of his many years of work. Escherichia coli acquired the ability to eat citrate after 33,000 generations of "natural" selection.
Life on Earth originated in the oceans. From simple to more complex, she came to aquatic animals, the basis of whose diet, as we found out, were and still are algae.

If E. coli needed such a long time for a random combination of two mutations that allowed it to switch from glucose to citrate, then the inhabitants of the ocean needed no less to switch from vegetarianism to protein food.
I will assume that it took not two mutations or even twenty-two to assimilate proteins. It is safe to say that this was a huge step of evolution, commensurate in scale with the landfall or the appearance of birds.
Surely biologists have their own numerical calculations on this issue, but for us it does not matter at all whether tens or hundreds of millions of years passed before the first predator appeared on Earth. The important thing is that for a very long time there were no predators at all.

What was left for the poor fish in this mysterious period? Food resources are in abundance, predators have not yet had time to appear. How, then, should the main driving force of evolution - survival - work if there is nothing to adapt to?
Finally, let's remember about sexual selection. That's where the power is! What living being can resist him? It makes hearts beat faster, does all sorts of stupid things and, of course, inherits evolutionary traits.

However, if you think with a cool head, then everything is not as smooth with sexual selection as we would like. The problem is that females should choose those males who have adapted to survival better than others and are better able to provide offspring with food than others. In unbearable conditions of abundance of food and lack of danger, this is quite problematic.

Of course, when predators eventually appeared in the world's oceans, everything got better, and natural selection took over the leadership of the evolutionary process. However, an involuntary question creeps in, how was the selection of hundreds and thousands of random mutations carried out for millions of years before that bright moment? How, finally, did the predators themselves appear without the leading and guiding hand of natural selection? How, in general, did evolution move in those almost heavenly conditions?

Perhaps I am not taking into account some other extraordinary factors of natural selection, which are not commonly reported in the scientific literature. Let's say beauty. I remember the sparkling phrase of Faina Ranevskaya: "Beauty is a terrible force." And why not? In the absence of other factors, this terrible force has shouldered the evolutionary process on its fragile shoulders.
Beauty saved the world! Or am I wrong? Then correct me.

* - I apologizes for my English. I would be grateful for the corrections.

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