To: Brumar89 who wrote (47364 ) 2/24/2014 11:34:13 AM From: Solon Respond to Evolution via natural selection is the basis of all of biology. Darwin’s explanation of evolution via natural selection is the basis of all of biology and its applied sub-disciplines of medicine, agriculture, and biotechnology. No other biologist in the history of our species has had an impact of this magnitude. In the words of the eminent geneticist Theodosius Dobzhansky, “Nothing in biology makes sense except in the light of evolution.”5 The paradigm shift from creation to evolution has moved intellectual endeavors from an untestable beliefs to a rational understanding that flows from the scientific method. This, in turn, has allowed a vast array of advances in knowledge. Darwinian implications Disease prevention depends on an understanding of evolution. Darwinian or evolutionary medicine6 explains how some disease symptoms, such as fever, may be a response favored by natural selection as a defense against pathogens. Some genetic diseases such as sickle cell anemia may allow differential survival of its victims in malarial zones—a phenomenon called a balanced polymorphism (genetic variation, e.g., blood types).4 This results in a deleterious gene (sickle cell) being maintained at a relatively high frequency in a population, even though it can be lethal in a double dose (homozygous), because it protects its carriers against malaria when present in a single dose (heterozygous). Evolutionary thinking explains the arms race waged by pathogens and hosts that prevents either from being eliminated completely. Darwinian reasoning easily explains the development of antibiotic-resistant bacteria through the flagrant overuse of antibiotics. A drug kills the susceptible bacteria leaving bacteria with a pre-existing resistant mutation to build up the next generation. Then when you actually need the antibiotic for a bacterial infection, patients and doctors find that the drug is ineffective. This is evolution, pure and simple. Species management has evolutionary consequences. A similar process occurs in agriculture with the overapplication of pesticides, and the formation of pesticide resistant pathogens, insects, and noxious plants. Australians are very familiar with the myxomatosis versus rabbit “arms race,” whereby the virus initially killed 99% of the non-native rabbits. The virus that causes myxomatosis was introduced deliberately in Australia in 1950, in an attempt to control exotic rabbit infestation. Given enough time, however, the surviving rabbits returned in force as the virus evolved in the direction of less virulence, and the rabbits were selected for more resistance to the virus.7 Kin selection has an evolutionary context. Evolutionary psychology and evolutionary ethics help explain the origin of morality.8,9 Peacemaking among non-human primates by the calming effect of mutual grooming to diffuse aggression may be seen as the precursor of what became morality in humans.10 Modern religions are recent human inventions—a mere few thousand years old. The antecedents of morality, on the other hand, clearly evolved before humanity, as reflected in the empathy exhibited by bonobos (Pan paniscus), and the reciprocity of chimpanzees (P. troglodytes).11 Kin selection, whereby an individual sacrifices for a close genetic relative, makes sense in an evolutionary context because some of the same genes of the individual making the sacrifice will be passed on by the kin who survives. This is referred to as inclusive fitness.12 The ancestry of the AIDS virus, HIV-1 (human immunodeficiency virus-1) has been traced to SIVcpz (simian immunodeficiency virus) carried by our closest living relative, the chimpanzees.13 This is not surprising from an evolutionary perspective. Somewhere in a high school today, there is a student whose future career may contribute to the control of the AIDS epidemic. What chance of that would there be if creationism were taught as science in high school? Biotechnology uses Darwin’s ideas. Biotechnology—whether in the form of genetically modified crops, designer drugs, gene therapy, or the human genome project—all derive from Darwin’s profound insight. Darwin had no knowledge of genes or chromosomes, or of how inheritance worked. This required additional input from the understanding of Gregor Mendel’s (1822-1884) genetic work. Darwin’s ideas led to DNA research. The modern evolutionary synthesis grew from Darwin’s explanation of natural selection and Mendel’s demonstration of inheritance augmented by the research of mathematically oriented population geneticists. This fusion of knowledge moved evolutionary science forward to the middle of the 20th century.14 James D. Watson’s and Francis Crick’s 1953 demonstration that the molecular structure of DNA allowed for genetic coding was a huge breakthrough that ultimately made it possible to sequence the three billion chemical base pairs that compose the human genome and identify the approximately 20,000-25,000 genes in human DNA.15,16 Recent discoveries in evolutionary developmental biology, known as evo-devo, have shown that very similar genes are present in very dissimilar animals. These body-shaping genes are controlled by DNA switches called enhancers that turn them on or off at various times in development. Such enhancers are a major factor in the evolution of anatomy.17
