PART IX — TERRESTRIAL ECOSYSTEMS 



Figure IX-5 — MAJOR WORLD BIOMES 



I Tundra 



| Northern coniferous (Taiga), 



Temperate deciduous. and rain forest 



[>>i£] Temperate grassland 



[ 1 Chaparral and Desert 



§ Tropical ram, deciduous, and scrub forest 

 Tropical grassland and savanna, and 

 Mountains (complex zonation) 



This map shows the distribution and location of the world's major biomes. Note that 

 except in the rugged mountainous regions of North and South America, the distribu- 

 tion of biome types tends to be along parallels of latitude. Such a situation suggests 

 the importance of temperature and rainfall, both of which are strongly dependent on 

 latitude. Studies of past climates and biome distributions also support this concept. 



ferred from primary producers to 

 secondary producers, but the re- 

 sponse of each herbivore depends on 

 the daily and seasonal cycles of tem- 

 perature, light, moisture, gas con- 

 centration, and such. Carnivores and 

 omnivores consume herbivores and 

 primary producers to form higher 

 levels in the food chain (see Figure 

 IX-6), but again it should be empha- 

 sized that each and every species 

 responds in a unique manner to the 

 energy state of the system and to 



cycles and fluctuations of energy, gas, 

 minerals, moisture, and the like. 



Man is now affecting the life- 

 support system of the planet earth 

 to a serious degree. Man is consum- 

 ing oxygen at a rate that may some- 

 day change the concentration of this 

 gas in the atmosphere, and at the 

 same time man is affecting the pri- 

 mary source of oxygen production 

 through pollution and other means. 

 Man is emitting to the atmosphere 



massive amounts of carbon dioxide 

 (CO-); these directly affect plant 

 productivity, since increased CO- in 

 the atmosphere implies increased 

 rates of photosynthesis. The in- 

 creased atmospheric CO2 concentra- 

 tions also imply potential changes of 

 climate. 



The living, green, photosynthesiz- 

 ing surface of the earth, with all its 

 associated organisms, has evolved in 

 synergism with the atmosphere. Each 



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