ECOLOGY AND WILD LIFE CONSERVATION 479 



Western Coniferous Biome. This forest extends from Alaska to 

 Mexico. The portion in the Rocky Mountains differs considerably from 

 that along the Pacific Coast, and they are often considered two regions. 

 The dominant trees are western yellow pine, Douglas fir, and several 

 other species of conifers in different regions and at different elevations. 

 This is a region of many large mammals such as the elk, Rocky Moun- 

 tain sheep, goats, and the grizzly bear. The birds and small mammals 

 belong to quite different species than those in the eastern mountains. 



Tropical Biome. In southern Florida occurs an extensive tropical 

 flora that is Caribbean in origin. The area is relatively free of frosts, 

 and most of the vegetation is evergreen. Many native species of palms 

 abound, including the beautiful royal palm, and nearly all the palms in 

 the world have been introduced. The crocodile occurs in the everglades, 

 and the sea cow also lives here. A tiny race of deer still survive on the 

 Florida keys. Great nesting colonies of egrets, ibises, herons, spoon- 

 bills and other tropical birds make the everglades a never-to-be-forgotten 

 sight. Among the air plants growing in these moist surroundings are 

 many species of orchids. Abundant marine life occurs along both coasts 

 of Florida, and sponge fishing is an important occupation. 



The Web of Life 



"Big fleas have little fleas upon their backs to bite em, 

 And little fleas have lesser fleas, and so, ad infinitum." 



The largest animals, such as the wolf and the cougar, prey on smaller 

 animals ; the hawk and owl prey on small birds and rodents ; the mink 

 and weasel prey on small rodents or fish ; the shrew and the mole feed on 

 insects and worms ; many insects prey on other insects, and aquatic insect 

 larvae feed on various organisms in the water ; large fish feed on smaller 

 fish and smaller fish feed on water fleas ; water fleas feed on protozoa 

 and bacteria. Eventually all food chains of predatory animals end in 

 some herbivorous animals. When the large animals die, they are eaten 

 by worms, insects, and vultures or destroyed by bacteria, and so they 

 too become part of a food chain in the web of life. Many food chains 

 lead to man. In a pond, protozoa eat bacteria and are in turn eaten by 

 water fleas which are eaten by smaller fish which are eaten by bass; 

 finally man catches and eats the bass and that chain ends. Some chains 

 are even longer, whereas others are much shorter as, for example, a rab- 

 bit eats clover and man shoots the rabbit for his dinner. Small animals 

 such as mosquitoes, bedbugs, lice, and ticks suck the blood from larger 

 animals, including man himself. Even insects are often covered with 



