Evolution: a different view with loss of traits; not Behe (Introduction)

by David Turell , Wednesday, September 02, 2020, 20:50 (1546 days ago) @ dhw

QUOTE: One of the lost genes, KLK8, is interesting because it is involved in the development both of sweat glands in the skin and of the hippocampus in the brain; cetaceans lost it during their transition from land back to water. The loss of this gene is linked to the development of a thicker epidermis and the loss of hair (hair is not adaptive in aquatic environments, where it creates drag and does not preserve body heat as it does in terrestrial animals).

dhw: I think this quote provides the clearest possible explanation of the whole process. Loss of genes does not mean that every single organism was planned in advance with its code implanted in the very first living cells. It simply means that as evolution progressed, and more and more species evolved, each new species would have jettisoned those inherited genes which were no longer needed. Hair genes evolved as protection against the climate, but what would be the point of your ancestors’ hair genes if you lived in the water and no longer needed hair? Just like organisms themselves, genes are subject to the process of natural selection - the same principle as shrinkage of the modern brain: cells that were no longer needed were discarded.

Neat sidesteps. The big issue is if advances always result from the loss of genes the info was available and revealed in the smaller DNA with each step. Natural selection could only study what it received in each new advance, which it obviously did not control.