EVOLUTION 309 



apelike men became extinct and left no living descendants. Such 

 failures have been recorded time and again in other lines of 

 descent and are therefore not unusual. Finally in the human 

 lines, the Neanderthal and the Cro-Magnon types were evolved 

 and one or both survived and left living descendants. The 

 apelike skulls of prehistoric men, characterized by prominent 

 orbital ridges over the eyes, sloping foreheads, and heavy jaws, 

 are present to a certain extent in modern primitive races of men. 

 The close resemblance between the human skeleton and the 

 skeleton of the gorilla may be noted in Fig. 180. Other apelike 

 characters, such as ears pointed above, and the presence of 

 unusual quantities of hair about the ears and over the entire 

 body, are also seen in some modern men. There seems to be a 

 closer resemblance between the young of man and the adult ape 

 than between the young of man and adult man. In the human 

 infant the great toe stands out and the foot is almost prehensile ; 

 the abdomen protrudes, the arms are longer in proportion to the 

 legs; and the grip in the hands is so great that if a three- weeks 

 old infant is permitted to grasp a stick, it can be lifted from the 

 ground by raising the stick. 



Man's advance over other animals has been due to the exercise 

 and development of ingenuity and intelligence rather than 

 physical strength, although the human body as a machine is 

 probably the most efficient mechanism known. The high degree 

 of adaptability of the human race, shown by its ability to live in 

 any climate and to move about over land, water, or through the 

 air is in keeping with the relatively unspecialized morphology 

 of the human body. In comparison with man, most mammals 

 show a greater degree of structural adaptation to special habitats, 

 as for example, the form of the body of the whale for an aquatic 

 habitat, the forefeet of the mole for digging, or the hoofs of the 

 ungulates for locomotion over a hard substratum, all of which 

 in each case restrict the animal in varying degrees to a certain 

 environment. Man has supplemented his rather meager natural 

 equipment for obtaining food and for providing protection from 

 destructive factors in the environment, by learning to use fire and 

 tools, to manufacture weapons and clothing, to build suitable 

 shelter, and to store food. These with the ability to speak, 

 and later to write, are the manifestations of an intellectual 

 development brought into being with the human brain. The 



