HI MAN EVOLUTION 



from Miocene ape to modern man. I will also list some seven 

 biological changes which illustrate some of the evolutionary 

 paths leading from our ancestors who neither used tools nor 

 symboled to our ancestors who did both. 



I will describe illustrations of some morphological features 

 of four primate genera which are passable candidates for being 

 on the main line of human evolution. I am not going to dis- 

 cuss the bony bumps and ridges over which the specialists love 

 to quibble, but rather, I want to stress the general evolutionary 

 changes on which most anthropologists agree. And I will em- 

 phasize changes which correlate with differences in behavior 

 (see also Washburn and Avis, 1958). 



Before discussing the fossils, I should mention that I will 

 use the term "hominid" to refer to the taxonomic family which 

 includes modern man and his ancestors as far back as they were 

 separate from the pongid family. I will use the term "hominoid" 

 to refer to the superfamily which includes the pongids and the 

 hominids, that is, the superfamily which includes both man and 

 the apes, living or fossil. I will try to restrict the term "man" 

 to members of the genus Homo, but I, as others, may be in- 

 consistent and use "man" to refer to any member of the hominid 

 line. 



Now let us look at the representatives of the four known 

 genera (see Le Gros Clark, 1955, 1959; and Howells, 1959, for 

 more extended accounts). 



REPRESENTATIVES OF THE KNOWN 



GENERA 



1. Proconsul 



Proconsul was one of the Early Miocene apes who lived 

 along the shores of Lake Victoria in East Africa about twenty- 

 five million years ago. This is the earliest ape whose skull is 

 well known from the fossil record. The work of Le Gros Clark 

 and Leakey (1951) and others tells us something about the rest 

 of the Proconsul body. The members of the species we are con- 

 sidering, Proconsul africanus, were animals about the size of a 

 big baboon or a rather large dog. They ran on four feet, but 



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