Fate had arranged

One day I was looking through a low-power binocular microscope at a newly arrived batch of adult Drosophila immobilized with a little ether, and was busily separating the different varieties with a camel’s-hair brush. To my astonishment, I came upon something very different: not a small variation such as red eyes instead of white, or neck bristles instead of no neck bristles. This was another, and very well-functioning, kind of creature with much more prominent wings and long feathery antennae. Fate had arranged, I concluded, that an example of a major evolutionary change in a single generation, the very thing Muller had said could never happen, should take place in his own laboratory.

The females

To learn the practical side of genetics, I spent many months working with fruit flies, Drosophila melanogaster tiny benign beings with two wings and big eyes. We kept them in pint milk bottles. We would cross two varieties to see what new forms emerged from the rearrangement of the parental genes, and from natural and induced mutations. The females would deposit their eggs on a kind of molasses the technicians placed inside the bottles; the bottles were stoppered; and we would wait two weeks for the fertilized eggs to become larvae, the larvae pupae, and the pupae to emerge as new adult fruit flies.

A great geneticist

Each plant and animal is exquisitely made; should not a supremely competent Designerhave been able to make the intended variety from the start? The fossil record implies trialand error, an inability to anticipate the future, features inconsistent with an efficient GreatDesigner.When I was a college undergraduate in the early 1950’s, I was fortunate enough towork in the laboratory of H. J. Muller, a great geneticist and the man who discovered thatradiation produces mutations. Muller was the person who first called my attention to theHeike crab as an example of artificial selection

A watch implies a watchmaker

The simplest one-celled organism is a far more complex machine than the finest pocket watch.And yet pocket watches do not spontaneously self-assemble, or evolve, in slow stages, on their own, from, say, grandfather clocks. A watch implies a watchmaker. There seemed to be no way in which atoms and molecules could somehow spontaneously fall together to create organisms of such awesome complexity and subtle functioning as grace every region of the Earth. That each living thing was specially designed, that one species did not become another, were notions perfectly consistent with what our ancestors with their limited historical records knew about life.

A watch implies a watchmaker

The simplest one-celled organism is a far more complex machine than the finest pocket watch.And yet pocket watches do not spontaneously self-assemble, or evolve, in slow stages, on their own, from, say, grandfather clocks. A watch implies a watchmaker. There seemed to be no way in which atoms and molecules could somehow spontaneously fall together to create organisms of such awesome complexity and subtle functioning as grace every region of the Earth. That each living thing was specially designed, that one species did not become another, were notions perfectly consistent with what our ancestors with their limited historical records knew about life.

The facts of variability

My reflection, when I first made myself master of the central idea of the Origin of Species,’ was, How extremely stupid not to have thought of that!’ I suppose that Columbus’ companions said much the same. The facts of variability, of the struggle for existence, of adaptation to conditions, were notorious enough; but none of us had suspected that the road to the heart of the species problem lay through them, until Darwin and Wallace dispelled the darkness.’Many people were scandalized - some still are - at both ideas, evolution and natural selection. Our ancestors looked at the elegance of life on Earth, at how appropriate the structures of organisms are to their functions, and saw evidence for a Great Designer.

Darwin and Wallace

There is no obvious reason why the principles which have acted so efficiently under domestication should not have acted under Nature . More individuals are born than can possibly survive .The slightest advantage in one being, of any age or during any season, over those with which it comes into competition, or better adaptation in however slight a degree to the surrounding physical conditions, will turn the balance, the most effective nineteenth-century defender and popularizer of evolution,wrote that the publications of Darwin and Wallace were a flash of light, which to a man who has lost himself in a dark night, suddenly reveals a road which, whether it takes him straight home or not, certainly goes his way .