Evolution in Action
Evolution in Action
{{nintentional, but it was still artificial. The important varieties of supergerms, suchicillin resistant Staphylococcus aureus, have not come about through mutation, nor have any superbugs.
Artificial selective breeding by humans is explanation enough - and even then we must remember that the germ still remains a germ. It has not evolved into something more complex." Written by Roger Kovaciny in
"Supergerms - Do they Prove Evolution?", in Creation Ex Nihilo, Vol. 11, No. 2, 1989 p:17
(8) "The introduction and widespread use of antibiotics is probably responsible for the spread of a formerly anonymous gene that has helped bacterial organisms survive for unknown centuries." Written by Dr Davis Smith (Harvard University) in the Journal of the American Medical Association, Vol. 200, No. 11, June 12, 1967 p:42
(9) Sickle cell anaemia is often given as 'proof' of mutation-driven evolution in action today. This mutation, although giving resistance to malaria, confers on the person a reduced oxygen carrying efficiency. These type of changes bring about an advantage for the individual in the special conditions, but they are of a disadvantage in the normal environment, proof again, that mutations are detrimental.
Over the 300 years African negroes have been in the USA, the percentage of the sickle cell genes in their population has declined from 22% to 0.25%. This illustrates that away from special conditions which favour damaged genes, selection favours the normally functioning genes. Charlotte J. Avers, "Genetics", PWS
Publishers: Boston (Massachusetts), 1984 p:559
(10) An 11 year experiment conducted by Californian researchers in Trinidad showed that if river guppies were moved to tributaries, their breeding habits changed. After 30-60 generations, the transferred population matured later, and had fewer, larger offspring. These changes were in response to the different type of predators in the tributaries. This experiment has been publicised as the first experiment to look at real evolutionary change under natural conditions. Unfortunately this experiment does not prove evolution. Like the selective breeding of livestock, the selection process acts in accordance with the genetic material already available in the population. No new genetic material, which is essential for evolution, has been proved to have been produced in the species. At the end of the experiment, the guppies were still guppies, only the environment had led to a modification in their behaviour. This experiment is actually scientifically inconclusive, as no attempt was made to return the adapted guppies to their original habitat. A switchback design of this type would have confirmed whether the changes were permanent or not. It is, however, very reasonable to expect that if returned, the guppies would have reverted to their original form. San Francisco Chronicle, July 26, 1990 p:A-7; US News & World Report, August 13,1990 p:60; Nature, Vol. 346, July 26, 1992 p:313
(11) "Such studies [as the River Guppy experiment] merely show that genetic variability of the kind postulated in the models can be exploited by selection: they do not prove that the invoked selective agents are actually responsible for producing the observed differences." Written by Brian Charlesworth in his article "Life and Times of the Guppy" in Nature, Vol. 346, July 26, 1992 p:313
(12) The resistance of rats to the anti-coagulant Warfarin seems to be an example of mutation causing evolution. Resistance is conferred by a change in the enzyme which helps in the manufacture of Vitamin K (the body's blood coagulating agent) which Warfarin previously interfered with. This is not caused by a new gene, but by damage to the existing one. Rats with these damaged genes are so inefficient in producing Vitamin K, that they require 13 times more of it in their food each day. This is another example of mutations producing harmful genetic changes. L. Burnet, "Exercises in Applied Genetics", Cambridge University Press: Cambridge (UK), 1988
(13) Ten-year-old children of today are 4 cm taller and 2 Kg heavier than their average counterparts were in 1970. Also, today's 12-year-old girls are 10 cm taller and 10 Kg heavier than similar aged girls in 1911. These statistics are often used as 'proof' that humans are evolving, but they are basically the result of environmental factors. Better nutrition, fewer infectious diseases and better medical care are the most probable causes. Sunday Telegraph, October 9, 1994 p:130