Prof Campbell: What is the real evidence that things actually skip generations? This most likely to be due to conditioning rather than DNA and inheritance.
Question 14
I may have missed it but does Darwin attempt to explain homosexuality in both humans and the animal world? What conclusions did he come to if any?
Prof Campbell: The possible selective advantage of homosexuality is highly controversial. Darwin dealt with the common trait of hermaphroditism, e.g. in barnacles, but didn't really deal with homosexuality.
Question 15
During the time of the Ediacaran fauna c600 million years ago when all of the species were said to be soft bodied how did the hard parts of organisms arise such as shells and scales etc if natural selection can only work on existing variation?
Prof Campbell: Hard structures are made either of precipitates of calcium carbonate or phosphate, and sometimes sulphate, or silicate precipitates. Scales are not 'hard' in this sense. The idea is that around 400 million years ago the amount of calcium and carbonate reached a critical level and produced the first 'shell'. This had a selective advantage against predators, and thus evolved bit-by-bit into the shells we are familiar with on the beach today. Bone and teeth evolved similarly, but millions of years later.
Question 16
The species of homo sapiens seems to be the peak of evolution. What is your view of natural selection on the human race currently particularly in developed countries. Do we still have survival of the fittest? Or do we have the reproduction of the least able as well as the most able? In which case what will be the long term effects of in effect negating the law of survival of the fittest?
Prof Campbell: There is no such thing a 'peak' in the evolution of a species, including humans. Variation within a population simply enables the species to adapt and evolve. When their genes run out of ideas the species sets off on a path to extinction.
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