794 



AJWW-t^j ivr '-: 



Cafifonua desert i eted idth an amaiinjg: variety of wild 



flowas and girasjej.. nsomst of wfaidi com|deie tbeir life cyde foom seeii 

 u> seed in a tew weeLs. The animah {Mresmt are Tq>tiks— litaids and 

 snakes—^ insects and bunovdi^ rodents such as die kangaroo lat and 

 pocket mDose^ bodi of which are aUe to live widmut drinking water. 

 br esiractiii^ water firam seeds and succulent cacti. The maiumals 

 for^ie at n%ht and remain in dieir buirows durii^ the day to niiniimie 

 water loss. 



Tfopjcvrf f €■■ Fofesf. Low-King; regions near the equator, with an- 

 nual rainEaJk of 90 incht» cv more, are characterized by thick rain 

 Iw esis , widi an enonnoos variety of plants and animals (Fig. 38.10). 

 No sii^iie ^ecies is |Mresent in lai^ enou^ ninnbers to be dominant 

 The valleys of the Amazm^ Orinoco^ Om^P and Zambesi rivers;, and 

 parts of Central America^ Madagascar. Malaya and New Guinea, are 

 covered with trt^cal rain fnests. The vegetation is very thid^ and 

 vertically stratified. Tall treess shrubs, vines and epiphyses such as or- 

 chids crowd together, and many animals, are arlxweal. Uving in the upper 

 layers of the vegetatkHO. McMokeis^ lemurs^ marmosets, sloths, anteaters, 

 many reptiles, a wealth of Imlliantly col<xed birds, butterflies, beetles, 

 WTtniws and other insects coffloprise the rich fauna of the rain forest. 



Marine Life Zones 



~ cover about 70 per cent of the earth's surface 



..21V rich fauna and flc»a. The mass of organisms 



~ rreds the mass of terrestrial animals and plants. 



'n even the greatest depths of the ocean. The 



ranges froai about 28° F. in the polar seas 



359. 



and have 

 living in 

 Ljvii^ s.: 

 tempera: 



to 90*^ F. or move 3pics, but the aimual range of variation in 



any locality is usuaiiy not mcnre than 10 degrees. The oceans are in 

 OHitinuous circidation Ixoug^ about by the trade winds and the rota- 

 ticMi of the earth. These currents, such as the famous Gulf Scream^ }^P^^ 

 current and Humboldt current, not only play a major role in the ecolog^ 

 of the oceans but also have marked effects on the climate and other eco- 

 logic factors of the adjacent land ma<!<p< The major cinrents circulate 

 in a clockwise fastiion in the northon hemisphere and in a counter- 

 clockwise direction in the southern hemisphere. The combination of 

 these cnrroits and die prevailing winds tends to cause upwellings of 

 cool water laden with nutrients frcmi the depths to the surface on the 

 west coasts of the continents. These upwellings on the coasts of Cali- 

 fornia, Peru and Portugal support large populations of sardines, tuna 

 and other fish. 



.All the phyla except the Onychophora, and all the classes except the 

 amphibians, centipedes, millipedes and insects, are well represented in 

 the oceans; ctenofrfiores, brachiopods, ecfainoderms, chaetognaths, and 

 a few lesser phyla are foimd only in the oceans. The ocean has clearly 

 demarcated regions characterized by di£Eerent physical conditions, and 

 consequendy inhabited by di£^ent kinds of animals and plants. Four 

 main regions are recognized: (1) the Hdof zone, the beach between the 



