Ornithology, Evolution, and Philosophy 123

330 10 Systematics and Classification
Fossil Hominids
Mayr’s first papers on fossil hominids were reactions against the extreme taxonomic
splitting of previous authors, whereby nearly every fossil find was described
as a separate species or even genus (1951g, 1963q). He combined Neanderthal and
Homo sapiens in one species and also lumped too much among the species of
Australopithecus. There is now no longer any doubt that there were two sympatric
taxa in this genus, one gracile and one robust, both perhaps consisting of several
species. Much evidence indicates the existence of several allospecies related to
Australopithecus africanus. Three factors contributed to the current uncertainty in
the proposed interpretations of the history of man: (1) New fossil finds, (2) a more
consistent application of geographical thinking to the ordering of hominid taxa,
and (3) the appreciation of the importance of climatic changes for the evolution of
hominids (1982d, 1997b). Stimulated by theories of S. Stanley and R. Wrangham,
Mayr (2001f, 2004a) has recently proposed an entirely new scenario of the whole
evolutionary development from chimpanzee to Homo sapiens.Thismodelisbased
on climatic changes in Africa and correlated changes in vegetation leading from
rain forest through a stage of tree savanna to the current stage of a widespread
bush savanna. New fossils are being discovered all the time and they may ultimately
decide how much of the proposed scenario has validity.
In his new proposals Mayr considered not only bones but also our improved
understanding of climate, ecology, and behavior. Some australopithecines probably
became adapted to the bush savanna when the climate in East Africa became drier.
They changed to terrestrial habits and became bipedal, made the first flaked stone
tools, may have constructed lances and evolved into Homo. Firewastheirbest
defense at camping sites. Selection rewarded especially ingenuity and brain power.
This resulted in an increase of brainsize from 450 to 700–900 cm 3 in Homo (which
eventually reached 1,350 cm 3 in Homo sapiens). The change from Australopithecus
to Homo of the bush savanna, although rapid, was populational and hence gradual.
Mayr has decisively contributed to the new interpretation even though some of
his historical narratives are bound to be refuted eventually. He stated (1993a):
“The evolution of man is permissible within the framework of Darwinism, but it
is not an inevitable consequence of it,” as suggested by the somewhat finalistic
interpretations of Huxley and Dobzhansky.
I include here Mayr’s reminiscences of the German anthropologist Franz Weidenreich
(1873–1948) whom he met at the American Museum during the war: “I remember
the famous anthropologist Weidenreich with a good deal of affection. He
was in Germany a well-known embryologist and anatomist who had made particularly
distinguished work with respect to the neural crest. When the Nazis came to
power he was fired and went to China to work at the medical school in Peking. It was
there that he got involved in the description of Peking Man, and did indeed an excellent
job not only of describing Sinanthropus but also Java Man and the later findings
in Java. Like all anatomists, he used a purely typological language and made a new
genus and species of nearly every discovery, but he seemed to realize that Peking
Man and Java Man were nothing but geographic races of the same species.