the mother cell. In modern biological terms, this is a mutation. Mutations are either totally irrelevant, or they can lead to marked changes in the behavior of the individual. They can be directly harmful, and such ‘mutants’ will be continually discarded from the large broods. Many diseases are in fact due to mutations. But sometimes a mutation can give an individual just that extra positive characteristic needed to hold its own in the struggle for existence.”
“Like a longer neck, for instance?”
“Lamarck’s explanation of why the giraffe has such a long neck was that giraffes have always had to reach upwards. But according to Darwinism, no such inherited characteristic would be passed on. Darwin believed that the giraffe’s long neck was the result of a variation. Neo-Darwinism supplemented this by showing a clear cause of just that particular variation.”
“Mutations?”
“Yes. Absolutely random changes in hereditary factors supplied one of the giraffe’s ancestors with a slightly longer neck than average. When there was a limited supply of food, this could be vital enough. The giraffe that could reach up highest in the trees managed best. We can also imagine how some such ‘primal giraffes’ evolved the ability to dig in the ground for food. Over a very long period of time, an animal species, now long extinct, could have divided itself into two species. We can take some more recent examples of the way natural selection can work.”
“Yes, please.”
“In Britain there is a certain species of butterfly called the peppered moth, which lives on the trunks of silver birches. Back in the eighteenth century, most peppered moths were silvery gray. Can you guess why, Sophie?”
“So they weren’t so easy for hungry birds to spot.”
“But from time to time, due to quite chance mutations, some darker ones were born. How do you think these darker variants fared?”
“They were easier to see, so they were more easily snapped up by hungry birds.”
“Yes, because in that environment—where the birch trunks were silver—the darker hue was an unfavorable characteristic. So it was always the paler peppered moths that increased in number. But then something happened in that environment. In several places, the silvery trunks became blackened by industrial soot. What do you think happened to the peppered moths then?”
“the darker ones survived best.”
“Yes, so now it wasn’t long before they increased in number. From 1848 to 1948, the proportion of dark peppered moths increased from 1 to 99 percent in certain places. The environment had changed, and it was no longer an advantage to be light. On the contrary. The white ‘losers’ were weeded out with the help of the birds as soon as they appeared on the birch trunks. But then something significant happened again. A decrease in the use of coal and better filtering equipment in the factories has recently produced a cleaner environment.”
“So now the birches are silver again?”
“And therefore the peppered moth is in the process of returning to its silvery color. This is what we call adaptation. It’s a natural law.”
“Yes, I see.”
“But there are numerous examples of how man interferes in the environment.”
“Like what?”
“For example, people have tried to eradicate pests with various pesticides. At first, this can produce excellent results. But when you spray a field or an orchard with pesticides, you actually cause a miniature ecocatastrophe for the pests you are trying to eradicate. Due to continual mutations, a type of pest develops that is resistant to the pesticide being used. Now these ‘winners’ have free play, so it becomes harder and harder to combat certain kinds of pest simply because of man’s attempt to eradicate them. The most resistant variants are the ones that survive, of course.”
“That’s pretty scary.”
“It certainly is food for thought. We also try to combat parasites in our own bodies in the form of bacteria.”
“We use penicillin or other kinds of antibiotic.”
“Yes, and penicillin is also an ecocatastrophe for the little devils. However, as we continue to administer penicillin, we are making certain bacteria resistant, thereby cultivating a group of bacteria that is much harder to combat than it was before. We find we have to use stronger and stronger antibiotics, until . . .”
“Until they finally crawl out of our mouths? Maybe we ought to start shooting them?”
“That might be a tiny bit exaggerated. But it is clear that modern medicine has created a serious dilemma. The problem is not only that a single bacterium has become more virulent. In the past, there were many children who never survived—they succumbed to various diseases. Sometimes only the minority survived. But in a sense modern medicine has put natural selection out of commission. Something that has helped one individual over a serious illness can in the long run contribute to weakening the resistance of the whole human race to certain diseases. If we pay absolutely no attention to what is called hereditary hygiene, we could find ourselves facing a degeneration of the human race. Mankind’s hereditary potential for resisting serious disease will be weakened.”
“What a terrifying prospect!”
“But a real philosopher must not refrain from pointing out something ‘terrifying’ if he otherwise believes it to be true. So let us attempt another summary.”
“Okay.”
“You could say that life is one big lottery in which only the winning numbers are visible.”
“What on earth do you mean?”
“Those that have lost in the struggle for existence have disappeared, you see. It takes many millions of years to select the winning numbers for each and every species of vegetable and animal on the earth. And the losing numbers—well, they only make one appearance. So there are no species of animal or vegetable in existence today that are not winning numbers in the great lottery of life.”
“Because only the best have survived.”
“Yes, that’s another way of saying it. And now, if you will kindly pass me the picture which that fellow—that zookeeper—brought us . . .”
Sophie passed the picture over to him. The picture of Noah’s Ark covered one side of it. The other was devoted to a tree diagram of all the various species of animals. This was the side Alberto was now showing her.
“Our Darwinian Noah also brought us a sketch that shows the distribution of the various vegetable and animal species. You can see how the different species belong in the different groups, classes, and subkingdoms.”
“Yes.”
“Together with monkeys, man belongs to the so-called primates. Primates are mammals, and all mammals belong to the vertebrates, which again belong to the multi-cellular animals.”
“It’s almost like Aristotle.”
“Yes, that’s true. But the sketch illustrates not only the distribution of the different species today. It also tells something of the history of evolution. You can see, for example, that birds at some point parted from reptiles, and that reptiles at some point parted from amphibia, and that amphibia parted from fishes.”
“Yes, it’s very clear.”
“Every time a line divides into two, it’s because mutations have resulted in a new species. That is how, over the ages, the different classes and subkingdoms of animals arose. In actual fact there are more than a million animal species in the world today, and this million is only a fraction of the species that have at some time lived on the earth. You can see, for instance, that an animal group such as the Trilobita is totally extinct.”
“And at the bottom are the monocellular animals.”
“Some of these may not have changed in two billion years. You can also see that there is a line from these monocellular organisms to the vegetable kingdom. Because in all probability plants come from the same primal cell as animals.”
“Yes, I see that. But there’s something that puzzles me.”
“Yes?”
