100 Evolution and the Fossil Record
of the credit? For one thing, Darwin was the right man at the right time. In 1844, the idea
was still too controversial and Chambers’s amateurish efforts only made people scoff at
the idea of evolution. By 1859, however, the time was right and many people were think-
ing along these lines (as Wallace’s independent inspiration shows). In addition, Darwin
had worked hard to build a sterling scientific reputation and was also a member of the
Oxford-Cambridge elite. He was not a radical from the lower-class medical schools of
London. Most importantly, Darwin put all the pieces together in one book and provided
two important concepts: the evidence that life had changed through time (the “fact” of evo-
lution) and a mechanism for how it occurred, natural selection (the “theory” of evolution).
He overwhelms the reader with example after example, so that by the end the conclusion
is inescapable.
Darwin’s ideas were controversial at first, but by the time he died in 1882, the fact that
life had evolved was universally accepted in all educated parts of the world (including most
of the United States). When he died, Darwin was hailed as one of Britain’s greatest scientists.
He was buried in “Scientists’ Corner” of Westminster Abbey, next to Isaac Newton and the
rest of Britain’s scientific geniuses. However, his mechanism of natural selection initially did
not fare so well. Many of Darwin’s critics could not imagine how it was sufficient to shape
organisms. Some argued that if favorable variations occurred, they would be blended out of
existence in a few generations by backcrossing with the normal strains of animals. Darwin
never solved this problem by the time he died in 1882.
Ironically, the solution had already been discovered in 1865 by an obscure Czech monk
named Gregor Mendel. He found that by breeding strains of pea plants in his garden, he
could produce very simple and mathematically predictable inheritance patterns. More
importantly, he showed that inheritance does not blend the genes of both parents but is dis-
crete, so that rare genes from one parent can seem to vanish for a generation but then reap-
pear fully functional in the next generation if the genes are recombined in a certain way.
Mendel’s work remained unknown until it was independently rediscovered by three dif-
ferent lab groups in 1900, when the time was ripe for appreciating his insights. Genetics
made enormous strides over the next 50 years, culminating with the discovery of the DNA
molecule and its role in inheritance in 1953.
The Neo-Darwinian Evolutionary Synthesis
Evolution is a change in gene frequencies through time.
—Theodosius Dobzhansky, Genetics and Origin of SpeciesEvolution is merely a reflection of changed sequence of bases in nucleic acid molecules.
—John Maynard Smith, The Theory of EvolutionAlthough the world had accepted the fact that life has evolved by the time of Darwin’s death in
1882, it was less convinced that his mechanism, natural selection, was sufficient to explain all
of evolution. Natural selection slowly lost favor as several different genetics labs rediscovered
Mendelian inheritance and then built new ideas of how evolution occurred. Paleontologists,
meanwhile, became even more heterodox, with some following Darwin’s mechanism, others
subscribing to some sort of inheritance of acquired characters (“neo-Lamarckians”), and