The origin of eukaryotes

John Maynard Smith

As I have said several times in this blog, the theory of evolution is now well established. However, it is far from explaining everything. Many mysteries still remain. I listed some of them in a previous post. A book by J. Maynard Smith and E. Szathmáry, The Major Transitions in Evolution (Oxford University Press, 1995), describes them in more detail.

One of these problems refers to the changes of level that have taken place in the history of life, which I made the central idea of ​​my book The Fifth Level of Evolution. As its title implies, during evolution, things have not happened in an orderly or stable manner. At various points, there were changes of state (similar to those in physics) where evolution passed a critical point that made it possible to reach higher levels and opened up huge new fields in the configuration space. These points are the following:

Paul Davies, popularizer of science

Paul Davies

Paul Davies came to the fore among scientists who devote time to popular science with his 1992 book The Mind of God, written in response to Stephen Hawking’s final words in his popular best-seller A Brief History of Time. In another post I talked about another of his popular books, The Eerie Silence. Here I am going to discuss two other books he has written.

The Last Three Minutes (1994): This book on popular science is a little behind the times, as it predates the standard cosmological model, but explains well the state of cosmology when the book was published, and many of the things it says are still valid. It says something very interesting: that the Big Bang theory by Lemaître (whom Davies does not name) should have been accepted long before its two surprisingly accurate predictions gave it a boost in the sixties, because there is another argument supporting it, that scientists of the 19th century should have noticed, but didn’t: If the universe were infinitely old, it would have died by now. It is evident that something that moves to a stop at a finite rate cannot have existed from all eternity. By the way, there is an error in this paragraph: Davies ignores the difference between what is eternal and everlasting, which was solved fifteen centuries ago by Boethius. And there is a major flaw when he says that the radius of the visible universe is 15 billion light-years, because he does not take into account the expansion of the universe. The correct radius is about 43 billion light-years.

Science Cannot Prove That God Does Not Exist

In several posts, I have pointed out that it is impossible for science to prove that God exists, just as it is impossible to prove that God does not exist. The reason is that the object of scientific inquiry is the material world, and God is not part of that world and is therefore beyond the reach of science.

In a previous post, I criticized a book that attempted to do the former, from the perspective of believers. In this post, I will criticize another book that attempts to do the latter, from the atheist perspective. It is M-E: The God Within, by Joseph R. Abrahamson.

Although the author claims to rely on the principles of logic and the scientific method, he makes significant errors that indicate his lack of in-depth knowledge of these disciplines. The argument he presents as proof that God does not exist, although not explicitly stated in the book, can be deduced from reading it and can be summarized as follows:

Phantoms in the Universe?

The Standard Cosmological Model has introduced in physics two new concepts that didn't exist before:

• Dark matter: It seems to be five times more abundant than ordinary matter, but we don't know what it is, what it's made of. We only know that it appears to be affected by gravity, and so far, its existence has been concluded in two different ways: a) By analyzing the rotational motion of galaxies, which seems to require that there is more mass in them than what we can see. b) By studying the cosmic microwave background radiation, which has served as the basis for adjusting the standard cosmological model.
• Dark energy: We have no idea what it is. Some speak of a fifth fundamental interaction (or force), the quintessence, which would join the four we know: gravitational, electromagnetic, strong, and weak. Others offer different explanations, none of which have received experimental confirmation. The hypothesis of its existence is supported by two observations: a) Analyzing the expansion rate of the universe, after the 1998 discovery that this rate is accelerating. b) By studying the cosmic microwave background radiation, which has served as the basis for adjusting the standard cosmological model.

Arguments against the theory of evolution

Drosophila melanogaster

Despite what I said in the last paragraph of my previous post, there are still well-intentioned people who oppose the theory of evolution (although this is very rare among biologists), and sometimes offer arguments to defend their way of thinking. I will consider some of those arguments here and offer my answers.

Answer: The claim that evolution has not been successfully reproduced artificially is mistaken. We have been doing this for thousands of years through artificial selection, which gave Darwin the idea of ​​natural selection. We have been doing it for decades in the laboratory in a controlled way, as this Wikipedia article explains: Experimental evolution. And this has been done not just with bacteria, which have a very short life cycle, but also with higher animals.

The theory of evolution, is it science?

In three previous posts (this was the latest), I wrote more or less the following words:

The scientific theory of evolution is strongly supported by data from other sciences, such as embryology, comparative anatomy, paleontology, biogeography, and molecular biology (DNA analysis).

Since, despite everything, there are still those who doubt the scientific nature of this theory, in this post I will expand on the previous paragraph, explaining in a little more detail the scientific data that favor evolution.

What is the theory of evolution?

Tree of Life

The theory of evolution, in its current form, asserts that the transformation of species (the evolution of life) depends on five factors:

1.      Spontaneous variations in the genome (mutations, genetic recombination, and other events that modify the genome).

2.      Spontaneous variations in the environment. This factor is often overlooked, as the environment is usually quite stable, although sudden changes sometimes occur that can have huge consequences.

3.      Inheritance, through which the variations that occur as a result of the first factor are passed on to offspring and are subject to the action of natural selection.

4.      Natural selection, which means that those individuals whose genome is best adapted to the environment will leave more offspring (at least statistically).

5.      The basic laws of the universe, which are currently represented by quantum theory and the theory of relativity.