Penn and Teller video  KjlFtU KjlFtU KjlFtU  Penn and Teller on Creationism

Creationism and “Intelligent Design”  The idea of evolution has been harshly criticized by religious fundamentalists since the publication of the Origin in  This has been especially true in the U.S.  Repeatedly, believers in the literal truth of the Bible have attempted to have alternatives to evolution (i.e., creationism) taught in the public schools and to have the teaching of evolution either banned or restricted.

Criticisms of Evolution  Evolution is “just” a theory.  Evolution is an “entirely random” process.  Evolution “promotes selfishness and cruelty”

Evolution is “just” a theory Evolution is “just” a theory  All scientific theories are backed by multiple lines of evidence A theory is not just a “hunch.” A theory is not just a “hunch.” All theories provide broad, overarching explanations for major aspects of the natural world and have been extensively tested over time. All theories provide broad, overarching explanations for major aspects of the natural world and have been extensively tested over time.

Evolution is “just” a theory  Other scientific theories Gravity Gravity Plate tectonics Plate tectonics Germ theory Germ theory  Evolutionary theory is overwhelmingly accepted by scientists

Evolution is “entirely random”  Evolution includes random and non-random components Mutations occur randomly. Mutations occur randomly. However, natural selection is completely non-random However, natural selection is completely non-random Natural Selection results in the spread of mutations that increase the survival and reproduction of the organisms that possess them. Natural Selection results in the spread of mutations that increase the survival and reproduction of the organisms that possess them.

Evolution is “entirely random”  Convergent evolution also demonstrates that evolution is non-random Similar body forms have evolved in distantly related groups in response to the same selection pressures. Similar body forms have evolved in distantly related groups in response to the same selection pressures. For example, bony fish, sharks, dolphins and penguins all show similar adaptations to swimming efficiently in water: streamlining and fins. For example, bony fish, sharks, dolphins and penguins all show similar adaptations to swimming efficiently in water: streamlining and fins.

Evolution “promotes selfishness and cruelty”  Natural selection favors traits that increase reproductive success Different conditions select for different traits Different conditions select for different traits Cooperative traits are beneficial under many conditions. Cooperative traits are beneficial under many conditions. Cruelty is a human concept Nature is not cruel. Rather Nature is pitilessly indifferent. Cruelty is a human concept Nature is not cruel. Rather Nature is pitilessly indifferent.

Creationism and “Intelligent Design”  The U.S. Supreme Court has prohibited the teaching of creationism in public schools because it violates the “establishment of religion” clause of the Constitution.  Latest attempt to insert creationism into schools is the idea of “Intelligent Design.”

Establishment clause  Establishment clause is part of the first amendment to the U.S. Constitution  “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof;”

Creationism and “Intelligent Design”  The concept of “intelligent design” is outlined most clearly in Michael Behe’s book “Darwin’s Black Box.”  The central idea in “intelligent design” is that some structures in the body are so complex that they could not possibly have evolved by a gradual process of natural selection. These structures are said to “irreducibly complex.”

Creationism and “Intelligent Design”  By “irreducibly complex” Behe means that a complex structure cannot be broken down into components that are themselves functional and that the structure must have come into existence in its complete form.

Creationism and “Intelligent Design”  If structures are “irreducibly complex” Behe claims that they cannot have evolved. Thus, their existence implies they must have been created by a designer (i.e. God, although the designer is not explicitly referred to as such).

Creationism and “Intelligent Design”  Behe’s main examples are various biochemical pathways in the body, the blood clotting system, and structures such as the bacterial flagellum.

Creationism and “Intelligent Design”  Since the publication of Behe’s book, it has been demonstrated repeatedly that things he has claimed to be irreducibly complex are not in fact so.  E.g. the flagellum in eel sperm lacks several of the components found in other flagella, yet the flagellum functions well.

Creationism and “Intelligent Design”  The blood clotting system in dolphins lacks at least one component that the human system has, yet it too is functional.  In addition, plausible gradual scenarios for the evolution of biochemical pathways including the Kreb’s cycle have been documented.

Evolution of complex structures  The evolution of complex structures, such as the eye, appears difficult, but natural selection achieves this by the slow accumulation of minor improvements from one generation to the next.

Evolution of complex structures  Each step on the evolutionary pathway from a simple light sensing cell to a complex eye capable of focusing and producing color vision, must be beneficial to the organism that possess it and a slight improvement on earlier versions.  It is not necessary for a structure to be perfect or even very good it just needs to be better than the alternatives to be favored by selection.

Variation in mollusc eyes from (a) pigment spot to (b) pigment cup to (c) simple optic cup in abalone to (d) complex lensed eyes in a marine snail and octopus.

Evolution of complex structures  Computer simulations suggest that eyes can evolve easily and in nature eyes have evolved independently more than 40 times.