February 1, 2009 (Vol. 29, No. 3)

Francisco J. Ayala, Ph.D., is university professor and Donald Bren professor of biological sciences, ecology & evolutionary biology, School of Biological Sciences, at the University of California, Irvine. Dr. Ayala is one of the world’s foremost evolutionary geneticists, whose academic distinctions and awards could stretch from his laboratory to the Galapagos Islands and back.

He is a major proponent of Darwin’s theory of evolution by means of natural selection, and a frequent speaker on the topic. Dr. Ayala also constantly defends evolutionary science against the anti-Darwinian/antinatural selection movement known as Intelligent Design.

Dr. Ayala’s research group carries out studies on the origin and evolution of introns and on the evolution and functional significance of pseudogenes and ectopic expression. They also continue to research questions related to the molecular clock of evolution. Since DNA and protein sequences can be used for reconstructing evolutionary history and timing events of the past, Dr. Ayala and his colleagues want to know “How good is the clock?” They are investigating a number of genes and testing new models of rates of gene evolution.

Another major research effort focuses on the population structure and evolution of parasitic protozoa, such as those which cause malaria and Chagas disease. Additionally, Dr. Ayala is interested in the philosophy of biology and in bioethics, as well as in the relationships between science and religion, including the teaching of evolution in schools.

Below are excerpts from a GEN interview with Dr. Ayala. The entire discussion can be heard as a podcast.

Dr. Francisco J. Ayala is one of the world’s foremost evolutionary geneticists and a major proponent of Darwin’s theory of evolution by means of natural selection.

GEN: You’ve written that Darwin’s discovery of natural selection is one of the most significant events in intellectual history because it completed the Copernican
revolution. Would you elaborate?

Dr. Ayala: In the 16th and 17th centuries, a great number of physicists, as we would call them now—Copernicus, Kepler, Galileo, and eventually Newton, among many others—initiated what is now known as the Copernican revolution, i.e., science in the modern sense of the word, science that proceeds by formulating laws and hypotheses and testing them by observation and experiment. It is science that looks for universal laws.

But these physicists left the living world out of that revolution. They thought that their discoveries applied to the earth as well as to the heavens. The same laws that explain the motion of bodies or the falling of bodies on earth also explained the motion of the planets and the stars in the sky. But living organisms were clearly “designed”, e.g., the eyes for seeing and the hand for grasping.

It was due to the genius of Darwin that he discovered what has come to be known as the the law of natural selection or, more accurately, the theory of natural selection, as a way to account for the design of organisms, and why the eye, for example, has all the parts put together for the purpose of seeing.

So natural selection can account for the design of organisms. Darwin brought into the realm of scientific explanation the living world, which had been left out by the Copernican revolution, and thus, completed that revolution because now everything in the world of nature was explainable by scientific laws.

GEN: You also note in your recent book, entitled Darwin’s Gift to Science and Religion, that Darwin considered natural selection, not evolution per se, as his theory. Yet history and many, if not most scientists, probably credit Darwin for the theory of evolution. Why is this the case?

Dr. Ayala: Well, it is all right to give credit to Darwin for the theory of evolution because he accumulated large amounts of information and evidence supporting this theory. But evolution was frequently accepted by biologists at the time, and theories of evolution had been proposed previously, most notably in 1809, the year of Darwin’s birth. A French scientist, Lamarck, had published a full theory of evolution.

But many scientists on the Continent, as well as in the U.S. and in Great Britain, weren’t quite willing to accept evolution. What was not known was how to explain evolution, how to explain the change of organisms over time, and critically, how to account for design.

The idea of natural selection came to Darwin shortly after his return from a trip that he took on the HMS Beagle around the world between 1831 and 1836. So we know from his notebooks that by late 1837 to early 1838, he had come up with the idea of natural selection, and he was extremely excited because he realized that he now had the explanation for design and, therefore, for evolution.

And as he pointed out in his notebooks, “Now I have a theory to work with.” For the rest of his life he conducted all sorts of observations and experiments. This seems, at first sight, strange that he would be using up so much time, years at a time, to investigate certain matters like the fertilization of orchids or the classification of barnacles and things of that sort.
He was looking for observations that could falsify his theory, if his theory was wrong. By the way, that’s the proper way of doing science—not trying to find evidence that is consistent with one’s theory, but that is actually contrary. Doing all these observations, experiments, and studies convinced him that his theory was correct.

But his theory was natural selection. This explained design and adaptation and, therefore, evolution. His discovery was how evolution occurred and how design came about.

GEN: Although Darwin and Alfred Russel Wallace independently came up with the idea of natural selection, you’ve pointed out that they viewed the concept of natural selection rather differently. What were those differences, and how
did those differences influence each man’s understanding of the process of evolution?

Dr. Ayala: Wallace was interested in explaining evolution, not in explaining design or adaptation. He was not aware that the main significance of the principle or the process of natural selection was that it could account for the design of organisms. He thought it was a way to explain evolution, and in particular, progressive evolution.
Evolution for Wallace was always moving forward and it would be constantly advancing. This was something that Darwin, based both on evidence as well as on the theory of natural selection, would not accept.

More from GEN’s Year of Darwin

Celebrating Charles Darwin in 2009

Podcast: Interview with Dr. Sean Carroll

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