The Greatest Show from Darwin to Dawkins -7

7. In front of your eyes

Finally, we are approaching one of the most interesting manifestations of evolution. Dawkins calls this phenomenon "rapid evolution" and gives two examples.
In the first, "in the case of elephants, we have good reasons to suspect the presence of strong selection against large tusks."
Published data from the Uganda Wildlife Department regarding elephants legally shot by hunters show the average tusk weight in the period from 1925 to 1958, according to which a statistically significant trend towards their decrease is visible.

"Maybe," Dawkins sums up, "the difference between individuals with large and small tusks is not genetic. However, I am inclined to seriously consider the possibility that this is a real evolutionary trend.…
We seem to have enough evidence to "bring a case" about the rapid evolution that took place right before our eyes, a case that could pay for future research."
Said–done!
I don't know who could pay for this research, but after spending a lot of time on the solution, I suddenly came to a simple conclusion.
Unfortunately, the statistically significant tendency to decrease tusks has a simple explanation that has nothing to do with the evolutionary approach. As a former hunter, I can testify that when there is a lot of game, and you have a license for one hare, then you leave every little thing alone until you meet a worthy specimen. And on the contrary, when there is little game, the hunter is ready to shoot anything that somehow resembles an unfortunate hare.

Uncontrolled shooting for the sale of tusks led to the almost complete extermination of elephants. There are no fewer poachers every year, despite the fact that the number of elephants is constantly decreasing.
Considering that elephants' tusks grow all their lives, we must admit that the desire of hunters to get the best prey leads to the fact that they simply do not allow the tusks to grow by inhumane shooting. So, as elephants are exterminated, poachers reap the fruits of their greed.
Here is such a "natural selection".
Another example of "rapid evolution" is more optimistic and concerns the Mediterranean lizards Podarcis sicula. These lizards feed mainly on insects and live on the island under Kopiste.

There were no lizards on the island near Markaru until 1971, when scientists transported five pairs of these lizards there. 37 years later, another group of scientists discovered a thriving population of lizards on Podarcara, whose DNA analysis confirmed that it was indeed Podarcis sicula. Scientists have suggested that the entire population originated from those five imported to the island.
The lizards of the island Under the Marquara, an "evolved" population, showed pronounced differences:
- significantly larger heads (longer, wider and taller) than the "original" population of the island Under Kopiste;
- massive jaw muscles and noticeably greater bite force;
- lizards have switched to a more vegetarian diet and eat significantly more vegetation;
- there have been significant changes in the intestines and caecum, which provides a home for bacteria and acts as a fermentation chamber;
- the caecal valves not found in Podarcis sicula "began to evolve," Dawkins reports, which apparently means that these valves appeared;
- the population density has increased, but the lizards have stopped protecting the territory, as did the "ancestral" population on Pod Kopist.
This example of "rapid evolution" requires closer attention. According to Dawkins, "The average period of generational change in these lizards is approximately two years, so the evolutionary changes observed on the Sub-Markaru represent only about eighteen or nineteen generations."

Well, there have been undeniably powerful changes in nineteen generations. In fact, there could be no more than eighteen generations, since the first individuals were born on the first island.
How could this happen in such a short time? Short not only for natural selection, but even for artificial selection. What prompted the lizards to such a violent mutation?
Let's try to go through the scheme: a random change, which today is called mutations, then - the survival of a mutated individual - the spread of a gene and a new random mutation. At the same time, we do not forget that "the rate of change will be so slow that we will not notice trends from generation to generation," as Dawkins aptly noted, explaining that "the reason why we do not notice changes from one generation to another is that in any century, variations within the current population will usually be greater than the variations between mothers and daughters."
Centuries in this case does not smell (only 37 years), and even the total enumeration of changes is at least six. Some: for example, behavioral, related to the protection of the territory, can be considered a consequence and excluded from the general list. However, it will not be possible to close your eyes to the caecal valves, caecum, intestines, more powerful jaw muscles and the transition to vegetarianism.

Let's assume that already in the first generation, born on the island near Markaru, the first mutation occurred. Due to the requirement of chance, one individual mutated. It will take several generations for this useful change to spread. Let's not forget about Mendel's law, and then it will take even more time to spread the next mutation in view of the multiple population growth and settlement on the island. Even if the mutations were one after another, and Podarcis sicula lived in a large Swedish family, it would still take an order of magnitude more than eighteen generations.

Let's, in order to somehow fit in the allotted time, decide that all the lizards unworthy of natural selection simply died out. On the island Near Markaru there was a serious shortage of insects and lizards, not inclined to vegetarianism, had to starve (for simplicity – die out), never reaching puberty.
Yes, it's cruel. But what to do, that's the theory. However, even under this condition, it is impossible to somehow enter the necessary mutations that occur, let me remind you, purely by chance in a timely manner.
STE is rushing to the rescue again, according to which all or part of the changes in the genes could have occurred completely unnoticed (which is called recessive). By the way, almost all of these mutations are most likely not new to lizards. Once their ancestors could have been herbivores and, therefore, the genes are already available.

However, if you think about it, they must have other genes that remember the period when the ancestors of lizards were fish. Why not, for the sake of the principle of chance, try this mutation, and at the same time thousands of others that have accumulated over millions of years of evolution?

The principle of randomness does not allow only the necessary mutations to occur sequentially, and harmful ones somehow magically did not happen. After all, the genes are not aware of what changes have occurred in the environment? Therefore, they are not able to produce exclusively the necessary mutations. It is already ubiquitous natural selection that will make a choice which mutation is useful and which is not, but it takes time for the choice to happen. And if there are initially only ten lizards, 37 years is clearly not enough even for a simple search of possible variations.

In addition, it is very desirable that mutations associated with the transition to a vegetarian diet occur simultaneously. What does it mean at the same time? It means in one generation. Yes, the lizard needs massive jaw muscles, significant changes in the intestine and caecum at the same time. Otherwise, natural selection will simply have no one to choose from.

Judge for yourself, what is the use of strong jaws if there is nothing to digest excess cellulose? Or how will valves and other changes in the intestine come in handy if there is nothing to grind cellulose with? One without the other is not just useless for their owner, but even dangerous.
Of course, if lizards had a million years left, then it would be another matter. The changes would have occurred imperceptibly for their digestion; and indigestion, most likely, did not happen.
Nevertheless, the facts say that despite all these difficulties, the lizards are safely alive and have changed just as much as necessary. No more, no less. And all in some eighteen generations!

I'm afraid that by offering us this, or any other example of rapid evolution, Dawkins may not notice all the contradictions with the theory that he so subtly and cleverly proves. Having formulated its postulates a few pages before, he immediately gives an example that does not fit into it on any point.
How do we rescue Dawkins? I honestly don't know. Unless we can only assume that our gullible professor fell victim to a prank by cheerful naturalists who, between the first and second landings, secretly brought lizards of a different species to the island under the Marquara. The first lizard settlers all died out, unable to withstand the pressure of natural selection, and the secretly imported ones multiplied safely.
Probably something like that. Or I don't even know.

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

Next: http://proza.ru/2022/07/02/766