Science on Wisconsin Public Radio

Professor Shakhashiri is a frequent guest of the Larry Meiller Show
on the Ideas Network of Wisconsin Public Radio.

Francisco Ayala - September 26, 2006 Larry Meiller Show

The Larry Meiller Show on September 26, 2006 featured special guest Francisco J. Ayala, Donald Bren Professor of Biological Sciences and Professor of Philosophy, University of California, Irvine. Professor Ayala was awarded the National Medal of Science in 2001. While in Madison, Professor Ayala gave two public talks, “Darwin’s Most Significant Discovery; Design Without Designer” and “From Biology to Ethics; the Biological Roots of Morality.” His talks were co-sponsored by WISL, The Center for the Humanities and the College of Engineering, University of Wisconsin-Madison.

Professor Ayala said Darwin’s most significant contribution was the discovery of natural selection. Copernicus and Newton proved a revolutionary concept, that heavenly bodies obey the same natural laws that pertain on Earth, but unlike heavenly bodies, the development and behavior of organisms could not be explained by natural laws. Darwin’s discovery of natural selection provided that explanation.

Professor Ayala provided an example of natural selection that can be duplicated in the laboratory. Take a test tube containing water, sugar and the amino acid histidine, a building block of protein which the bacteria can’t make for themselves. Add a few bacteria and within two days or so, the tube will contain billions of bacteria. Add a drop of streptomycin, an antibiotic, and most of the bacteria will die. However, a few which have resistance to the antibiotic due to random mutations will survive, and in a few days there will again be billions of bacteria in the tube, most of them resistant to the antibiotic. Take away the histidine and most of the bacteria die, but a few with random mutations that allow them to make their own histidine will survive. Within a few days there will again be billions of bacteria in the tube, all of them able to make their own histidine. Professor Ayala said the eye developed in the same way, starting with a few light-sensitive cells which gave ancient animals a competitive advantage. They reproduced, passing on the ability. Subsequent mutations developed the ability to sense light further until finally arriving at the sophisticated eyes of modern animals.

Professor Alaya says there’s no reason to think that humans are through evolving. There is a great deal of variation within the human population and mutations continually arise, so the species responds to changes in the environment. For example, human populations that rely heavily on milk as a food source have developed lactose tolerance in adults, a trait that gives them an advantage. In many human populations, adults are lactose intolerant. Some populations and some individuals also have more natural resistance to various diseases. As humans respond to new changes in the environment, such as new types of pollution or psychological stress, evolution will continue. Professor Ayala said what evolution can’t tell us is where we are going.

A caller asked why Darwin delayed so long in publishing his findings. Darwin’s diaries make it clear that he got the idea of natural selection in 1837, shortly after returning from his famous five year voyage as the naturalist on a British Navy surveying expedition. Darwin shared his early drafts with some other scientists and planned a large, multi-volume work, but he realized how revolutionary his idea was. He knew it had to be well supported and he wanted to collect as much evidence as possible. Darwin also knew that his idea would be interpreted by some as an attack on religion. Darwin was quite religious himself, having studied for the ministry, and his wife was very religious, and he wanted to avoid conflict. Darwin’s hand was forced in 1858 when he got a letter from a young scientist named Alfred Wallace outlining the idea of natural selection and asking for his comments. Darwin then wrote a single volume work, the famous Origin of Species, published in 1859. Wallace admired Darwin and, realizing that Darwin had worked on the idea for years, gave him credit for the discovery.

The British scientific community mostly supported Darwin, but natural selection met with considerable resistance from the public and from religious leaders who believed he was trying to remove God from the process. But Professor Ayala said many theologians eventually realized that Darwin is religion’s best friend because it solves the problem of evil. The question of why God tolerates evil has been a longstanding problem for theology. But Professor Ayala said just as geology shows that earthquakes are the product of natural laws, not the wrath of God, natural selection shows that the selfish and violent tendencies of humans are also a product of natural laws and not a curse from God.

A caller asked about “evolutionary psychology” or the evolution of cognition. Professor Ayala said some scientists think that cognition is made up of several components which evolved separately, though this is not accepted by everyone. The big question is how the mind–consciousness or self-awareness–came to be. In recent years, genes have been discovered that make human brain development different from that of our nearest relatives, but Professor Alaya says it’s still not understood how physical, chemical signals between neurons attain the unity of self-consciousness. He said this is one of the most challenging mysteries facing science.

Another caller said science should be separated from religion, but said Professor Alaya let religion into the debate by bringing up his explanation of evil. The caller also said evolution and natural selection are only theories that are not supported by the fossil record. He said there should be millions of transitional animals from one type and one species to another, but there are none. Professor Alaya said the caller was mistaken–many transitional species have been discovered, the most famous being the early bird Archaeopteryx, which had wings and feathers but teeth like a reptile. Professor Ayala said it was about as intermediate as you could ask for. Recently a new species has been discovered that’s intermediate between fish and amphibians, and Professor Ayala said thousands of fossils have been discovered of different human-like species which evolved after the human line split from chimpanzees about six million years ago (in some cases it’s still uncertain which ones are our direct ancestors.). As for mixing science and religion, Professor Ayala said evil is not discussed in science classes, though some theologians welcome natural selection as the explanation of evil. Traditionally, evil has been divided into at least two types. Sin has been regarded as the price we pay for freedom–God wants us to be free, but that means we can choose evil. Professor Ayala called the second type “physical evil” such as natural disasters. Just as science shows that earthquakes are not caused by God to punish us, so natural selection explains the apparent cruelty in the world. He said that chimpanzees like to hunt monkeys for meat and sometimes seem to delight in torturing the monkeys before eating them. Professor Ayala said God did not design chimps to torture monkeys–their behavior is a product of natural selection. In reference to intelligent design, the claim that God either designed humans and other animals as they are or guided evolution, Professor Ayala said any designer making the human birth canal such a tight fit for a baby’s head would be fired.

Larry asked Professor Ayala to summarize by asking what the relationship between science and religion should be? Professor Ayala answered, “Respect.” He said science and religion are the two great pillars of American life. Science gives us knowledge and a high standard of living while religion gives us purpose and values. He said we get values from religion which we can’t prove by science.

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SCIENCE on Wisconsin Public Radio

Science Fridays on National Public Radio

SCIENCE on
Wisconsin Public Radio

Science Fridays on
National Public Radio