ZOOLOGY 



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ZOOLOGY 



societies for their protection. This interest 

 becomes even keener when we learn that a 

 close relationship exists between animals and 

 man. The study of the habits, structure and 

 relationship of animals and their distribution 

 over the earth has developed into a science, 

 known as zoology. The name is derived from 

 two Greek words meaning animals and account. 



Relationship. Zoology is associated with 

 botany in one great science, called biology, 

 which embraces the study of all. living things. 

 It seems a simple matter to distinguish animal 

 from plant life when we pass through a wood- 

 land filled with plants of many kinds and ob- 

 serve the squirrels and birds chattering in the 

 trees, butterflies flitting from flower to flower, 

 and rabbits and toads hopping across our path ; 

 but the simplest animals and plants possess so 

 many characteristics of both forms of life that 

 it is difficult if not impossible to tell which is 

 plant and which is animal. 



An even closer relationship than this exists 

 between all animals. Man and the horse which 

 bears his burden, tie sheep, cattle, fish and 

 birds which furnish him food, the insects which 

 hide in the flowers of his garden all the won- 

 derful forms of animal life are descended from 

 one simple organism. 



How Animals Survive. The animals living 

 to-day are the descendants of the hardiest of 

 their species, which were so adjusted to the 

 conditions of life about them that they were 

 able to survive in the war with famine and 

 death. They are especially adapted to the 

 climate and geography of the locality in which 

 they live ; they are fitted to procure food ; to 

 maintain themselves among rival animals, and 

 to defend themselves and their young. The 

 divergence of species and classes is due to tin Mi- 

 adaptation to different environments, to 

 heredity and to the survival of only the fittest 

 species. 



For self-protection animals are equipped with 

 various weapons horns, venom, claws, etc. or 

 they possess coats harmonizing in color with 

 tli. ir surroundings, such as tin- \\lntr fur of tin- 

 polar bear and arctic wolf, the spotted coat of 

 the tiger, the changing color of the chameleon 

 and of numerous small animals, birds, fish and 

 insects. The greatest adaptation in appearance 

 occurs among insects. Some, such as the dead- 

 butterfly and the green-leaf insect, arc 

 similar in shape, as well as in coloi 

 object upon which they live. Other species, 

 which Invr no natural means of j> 

 mimic m color the more dangerous varieties of 

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their kind, the mimicry being the result of a 

 gradual development through a long line of an- 

 cestors. 



As a means of protection, animals are also 

 provided with special senses and instincts which 

 are developed to different degrees of keenness 

 in various classes. 



Division of the Animal World. The great 

 animal kingdom is divided according to general 

 structure into the following subkingdoms: 



The protozoa ("first animals"), such as the 

 amoeba, the radiolaria and the infusoria. 



The coelenterata (animals having hollow in- 

 testines), such as the jellyfish, coral and polyp. 



The echinodcnns (spiny-skinned animals), 

 among which are the starfish, the sea urchin and 

 the sea cucumber. 



The vermes, or worms, limbless, creeping forms, 

 like the earthworm. 



The mollnsks (soft-bodied animals), including 

 the oyster, snail, cuttlefish and the like. 



The arthropoda (jointed-foot animals), such as 

 the spider, lobster, centipede and innumerable 

 forms of insects. 



The vertebrates (backboned animals), includ- 

 ing man and the other mammals ; birds, amphibi- 

 ans, fish and reptiles. 



These subkingdoms are divided into classes 

 according to certain physical distinctions, such 

 as hair, feathers, scales, etc., and each class is 

 made up of a number of orders, which include 

 various families. The latter division, as, for 

 example, the cat family, includes many genera 

 (plural of genus), such as the lion, the lynx and 

 the domestic cat, and each genus embraces 

 many species. See CLASSIFICATION. 



History. With childish delight and cre- 

 dulity, the ancients treasured legends of strange 

 animals of distant lands and the deep seas, and 

 in fable they attributed marvelous charact< 

 tics to them. Many of the tales of this legend- 

 ary period were later confirmed by travelers 

 and navigators, who brought back from their 

 journeys specimens which proved their reports. 

 These early collectors founded the ancient 

 study of zoology, which w.us merely a descrip- 

 tion of different animals which were thought to 

 be entirely unrelated. 



The earliest scientific investigator into ani- 

 mal life was the Greek philosopher Aristotle, 

 who lived 350 years before Christ He dis- 

 sected various animals and made a classifica- 

 tion of the known species. I'mil the sixteenth 

 century, the knm\ ledge of animal structure 

 t no deeper than the views of Aristotle, but 

 in ti . \\heii the whole civilized world 



awakened to a spirit of discovery and ex- 

 ploration, the scientific d< it of O- 

 ology began. The inquiry into the relation of 



