= an a ee , a se 
wae ty i. oth SH FORT TG 
22 AN OUTLINE OF THE THEORY. 
d) Classification. The so-called Tree of Life. ‘All 
living forms can be arranged in a diagram called the 
Tree of Life. The Tree has a short trunk, indicating 
common origin of the living from the non-living, and is 
divided into two large trunks representing plants and ani- 
ne mals respectively. “From each of these start large 
branches representing classes, the larger branches giving 
_ off smaller branches representing families, and so on with 
smaller and smaller branches representing orders and 
genera, until we come to leaves as representing species, 
the height of the branch from which they are hanging 
indicating their place in the growth of the great life-tree.” 
(Clodd, “Story of Creation,” p. 103.) There is an exact 
gradation from the lowest life forms to the highest. 
First such simple forms as the sponges and corals, then, 
through the worms, crabs, oysters, and snail to the fish, 
and thence through amphibia, reptiles, beasts of prey, 
ungulates (hoofed animals) and apes to man. Evolu- 
tionists say that in this gradation of life we see illustrated 
the evolution of complex from simple forms. 
The Descent of Man. 
According to the evolutionary hypothesis man is re- 
lated to the animal kingdom by descent from a brute an- 
cestor, who, apelike in appearance, is the common ancestor 
of ape and man. The evidence of such derivation is be- 
lieved to be: 
1. Rudiments of structure which were useful in 
some brute ancestor. There remain in man a few ele- 
mentary muscles for twitching the skin, as in the fore- 
head; and it is pointed out that many animals have such 
muscles at the present time, and it is argued that the 
ability of some men to move the whole scalp points to the 
existence of muscles with such function in our brute an- 
cestors. The vermiform appendix in man is termed rudi- 
