The Unintelligence of Design

1. The Unintelligence of Design Terri Felton Evidence for Evolution March 28, 2006

2. The Argument: “The theory of intelligent design (ID)holds that certain features of the universe and of living things are best explained by an intelligent cause rather than an undirected process such as natural selection… In a broader sense, Intelligent Design is simply the science of design detection -- how to recognize patterns arranged by an intelligent cause for a purpose.” --Intelligent Design Network

3. For What Purpose? Some Examples of Unintelligent Design

4. “The Panda’s Thumb” • Five digits, plus a “thumb” • Used for grasping bamboo – a “channel” between two pads on the forepaw • Question: Was this structure “designed” this way? Photos: bcps.org, giant-panda.com, mccullagh.org

5. Not a Digit • Enlargement of the radial sesamoid • “True thumb” is 1st digit; not opposable • Musculature responded to sesamoid growth, allowing it to function as a “thumb” • Tibial sesamoid also enlarged Photo: Athro, Limited

6. The Argument: • The panda, as a relative of carnivorous bears, developed its “thumb” through natural selection for grasping bamboo • If pandas were originally designed to have opposable thumbs, wouldn’t they have structures similar to primates, which are more efficient? • How might this argument be countered?

7. Human Examples Lowered larynx in humans versus primates: Adapted for speech, but creates increased risk for choking Illustration: Martin Nickels, 1998

8. Small pelvic opening necessary for upright walking (legs close together) Large skull size to accommodate larger human brains Illustration: Martin Nickels, 1998

9. Recurrent Laryngeal Nerve • Originates from the vagal nerve, then extends down the neck into the chest, and then back up to the neck again • In fish, this nerve follows a straight line Illustration: www.voiceproblem.org

10. The Vertebrate Eye Retina is “inside out”: • Photoreceptor cells point away from light, with the “wiring” passing through the retina to create a blind spot • Why might the eye be “designed” in this way? Illustrations: wikipedia.com

11. The Arguments: Evolution argument: • Inverted retina resulted from the development of a neural tube out of an originally flat, light-sensitive layer • PBS Evolution Library: The Eye Opposing argument: • Retina is inverted to take advantage of the nutrient-rich capillaries just outside the photoreceptors How might one respond to either argument?

12. Vestigial Structures Evolution would also predict that species occupying very distinct environments from that of a common ancestor might show vestigialstructures — structures obtained from a common ancestor but no longer needed for the original adaptive function. Rudimentary tooth in lower jaw of a baleen whale The pelvic girdle seen in reptiles and mammals as an adaptation for support in tetrapods, is vestigial in whales — it is a “fossil” footprint of their ancestry and serving no function today in swimming descendants of tetrapods. Sources: top - Young, 1992; lower - http://www.lclark.edu/~seavey/genetics04/home.html

13. Vestigial Structures Wings on flightless birds • Balance for running • Courtship displays • Why wings? Eyes on blind cave fish • Surface-dwelling species has fully-functioning eye • What purpose does the eye serve in the cave-dwelling species? Photos: livescience.com

14. Vestigial Structures - Plants Parasitic and non-green dodders retain “fossil” non-functional chloroplasts (photosynthetic organelles) with reduced cpDNA in their cells as a vestigial structure inherited from a common ancestor with morning glories Cuscuta - dodder Ipomoea - morning glory Source: Ken Sytsma

15. Vestigial Organs - Humans Appendix: • Left behind from a plant-eating ancestor? Tailbone: • May support pelvis and anchor minor muscles Wisdom Teeth: • Ancestral jaws larger? • Better hygiene? Illustrations: livescience.com

16. Vestigial Behaviors Erector pili muscles: • Cause hair to stand on end to make one look larger and keep the body warmer • Humans have less body hair than ancestors • Why might this behavior remain? Illustration: BBC Eureka TV Photo: www.hunterian.gla.ac.uk

17. Questions for Discussion: • Does the work of a “designer” imply perfection? • Does imperfection in and of itself provide evidence for evolution? • How does one provide evidence for evolution through the imperfections given in this presentation? • What might be some counterarguments?

18. Resources • Davis, D. Dwight. The Giant Panda, a Morphological Study of Evolutionary Mechanisms. Chicago Natural History Museum, 1964. • Dawkins, Richard. The Blind Watchmaker. New York: Norton and Company, 1986. • Denton, Michael J. “The Inverted Retina: Maladaptation or Pre-adaptation?” Origins & Design 19:2 Issue 37. • Gould, Stephen Jay. The Panda’s Thumb: More Reflections in Natural History. New York : Norton, c1980. • Nickels, Martin. "Humans As a Case Study for the Evidence of Evolution“. Reports of the National Center for Science Education 18(5), Sep/Oct, 1998, pp.24-27. • Young, David. 1992. The Discovery of Evolution. Cambridge Univ Press. • http://www.athro.com/evo/evframe.htmlht • http://www.livescience.com/animalworld/top10_vestigial_organs.html • http://www.nyu.edu/projects/fitch/courses/evolution/html/examples_of_adaptations.html