Evolution vs. (not so) Intelligent Design
This is the recap of a talk given at the Feburary 12, 2006 CDHS monthly meeting.
Three biology specialists discussed evolution and Intelligent Design in honor of Darwin’s birthday. Dr. Sam Bowser, a research biologist from the Wadsworth Center Department of Health, explained the basic premise of Intelligent Design (ID) and detailed the flaws in one common ID argument. Dr. Susan Jenks, an assistant professor at Russell Sage with a joint appointment in Psychology and Biology, wowed us with her discussion of the evolution of female spotted hyena genitalia. Melissa Joslin, a biology teacher at Averill Park High School, engaged audience volunteers in an evolution lab demonstrating Darwin’s insight through observing finch beaks.
Dr. Sam Bowser discussed the Fordham Foundation’s rating New York as average in the teaching of evolution in 2000. Their main issue with New York standards was the use of the term “design” even though it did not include Intelligent Design. On February 4, 2005 a New York Times editorial discussed teachers’ fear of merely saying the word “evolution” in class because of angry calls from parents. Sam explained that school boards are held captive by politics. Daniel Hooker introduced New York State Assembly Bill A08036, which would force schools to teach the evolution “controversy” from kindergarten through high school.
Intelligent Design is an untestable philosophical argument that declares that biological systems are irreducibly complex and show design by a yet-to-be-identified supernatural intelligence. Although most people define this supernatural intelligence as God, Goddess, or Gods, some say aliens could be responsible. Sam then demonstrated his keen sense of Humanist fashion with a T-shirt of the Flying Spaghetti Monster – yet another supernatural intelligence candidate (interested readers should visit www.venganza.org for more information on Pastafarianism).
Sam dissected chapter 3 Darwin’s Black Box: The Biochemical Challenge to Evolution, by Michael Behe, an ID proponent. Behe wrote that the cilium, a hair-like structure on some cells, is an irreducibly complex structure. The cilium requires 200 proteins to beat like a whip and propel the cell; if any one of these proteins is missing, the cilium does not function. According to Sam, biologists have not studied the cilium closely yet. During embryogenesis (early embryo development), each cell has one cilium that does not beat. Adults have cilia in their kidney tubule cells that lack some of the structures needed to beat. Biologists used to think that these cilia were vestigial remnants. Sam investigated further with several graduate students by growing kidney cell on a membrane. They questioned whether propulsion was the only function of cilia and hypothesized that cilia might be sensory structures that sensed fluid flow through the tubule. By measuring the experimental flow field across the membrane, they determined the rigidity of the cilia and discovered that they were perfectly suited to be flow meters that would signal cells to pump out electrolytes. In conclusion, cilia are not irreducibly complex because they can loose part of their structure and still retain a function. Further study is necessary to confirm this hypothesis that cilia first evolved as sensory structures. Sam ended his talk by explaining that scientists debate the method, tempo, and details of evolution, but they do not debate evolution’s existence.
Dr. Susan Jenks quickly grabbed the audience’s attention by posing the central question of her talk: why does the female spotted hyena have a “penis”? Could this hypertrophied clitoris be intelligently designed? Spotted hyenas are ferocious bone-cracking carnivores in sub-Saharan Africa. Hyenas first appeared about 25 million years ago during the Early Miocene. Only four of roughly one hundred species remain.
Susan explained how she studies different evidence, such as DNA and morphology, to understand how the spotted hyena’s hypertrophied clitoris evolved. She used Robert Moss’s analogy of cheating paper writers to demonstrate the method: by mapping the differences between copied papers, one can figure out who copied from whom. The more differences there are between two papers (or two organisms), the greater the distance of their relationship. For example, civet cats and some lemurs have enlarged clitorises that are simpler than that of the spotted hyena, which means that they are probably more closely related than other mammals with smaller clitorises.
Environmental differences may be responsible for hyena clitoral evolution. Spotted hyenas live in groups and greet each other by sniffing each other’s genitals. Female spotted hyenas are larger and more dominant than the males, who must be careful and quick during mating. They often give birth to twins, who have a full set of strong teeth and come out fighting. Newborn siblings tend to fight and even kill each other. Spotted hyenas hunt in groups and are extremely competitive within their clans. They fight for their place in the matrilineal society. Cubs born of subordinate females form coalitions against the highly born cubs.
Susan brought several spotted hyenas to Berkeley as part of an ongoing research program. In female spotted hyenas, the vagina traverses the penile clitoris. With such a long passageway, the placenta has to detach from the uterus during birth because the umbilical cord is too short otherwise. Considering that the birth canal is bent, the penile clitoris appears to be a poor design.
One evolutionary theory is that female masculinization evolved as a byproduct of natural selection for aggression when members of a clan fight over carcasses during feeding. However, female hyenas have normal levels of androgens (male sex hormones). Perhaps ovarian androstenione, which causes testosterone in the placenta, causes masculinization of fetal genitalia. But experiments with antiandrogen drugs did not produce female hyenas with “normal” genitals compared with other mammals. Thus the evolutionary mechanism is probably nonandrogenic.
At this point we do not understand why female spotted hyenas have hypertrophied clitorises. But not knowing the answer does not mean that it is too complex to explain. Susan assured us that Darwin gave us the tools to work intelligently to figure it out.
Melissa Joslin discussed the mandated teaching of evolution in New York State high schools. New York State requires biology teachers to explain the mechanisms and patterns of evolution and teach their students about mutation and gene inheritance. In Honors Biology, the course starts and ends with evolution, and evolutionary principles are infused throughout the curriculum. The basics of evolution studied in class include variation, inheritance, selection, time, and adaptation. Students study evolution from the cell through complex life forms. In advanced classes students get their own DNA sequenced to study the Out-of-Africa theory of human evolution (the idea that the human species evolved in Africa and then migrated throughout the rest of the world).
Melissa set up the mandatory evolution lab “Beaks of Finches” for us. Several audience volunteers used a variety of tools such as tweezers, pliers, and bag clips to simulate finch beaks. Each volunteer had to collect as many seeds from a pie dish “island” as possible (but one at a time) into a cup. After two rounds of timed “feeding,” those who had fewer that 13 seeds average in their cup had to migrate to a new “island” with different seeds. Those that still could not collect at least 13 seeds average after two new rounds of feeding died. Sue, with the tweezers beak, was the lone survivor at the end of the competition.
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