. Biology and man. Biology; Human beings. Oxygen in air k Respiration Green .- {f:":^' ;- plants; >â â - ^^-; â -â ^ .!#*-» Fire ^ / 1 ^ Photo- Respiration | / ^ synthesis '^' N Photo- \ F^ synthesis 3^ Carbon dioxide in air K't >/ »y Bodie Carbon and oxygen m '. ,ee5 ^y soil ^! .^1^ ^5 ,^^ Bodies Excretion ^Q'j :';f ^j^ Herbivores .; A- Omnivores *^., Food Carnivores THE CARBON-OXYGEN CYCLE The material of green plants consists in part of carbon derived from the carbon diox- ide of the air. This carbon is passed on to animals as food, or returned to the air by respiratio
. Biology and man. Biology; Human beings. Oxygen in air k Respiration Green .- {f:":^' ;- plants; >â â - ^^-; â -â ^ .!#*-» Fire ^ / 1 ^ Photo- Respiration | / ^ synthesis '^' N Photo- \ F^ synthesis 3^ Carbon dioxide in air K't >/ »y Bodie Carbon and oxygen m '. ,ee5 ^y soil ^! .^1^ ^5 ,^^ Bodies Excretion ^Q'j :';f ^j^ Herbivores .; A- Omnivores *^., Food Carnivores THE CARBON-OXYGEN CYCLE The material of green plants consists in part of carbon derived from the carbon diox- ide of the air. This carbon is passed on to animals as food, or returned to the air by respiration or by burning. Animals either pass on the carbon to other animals which eat them, or return it to the air by respiration. Some of the carbon is locked temporarily in the soil as excretions or as dead bodies. Through decay, the action of bacteria and fungi, this carbon is returned to the air as carbon dioxide water, through the soil and other organisms. And while the atmosphere is nearly four-fifths uncombined, or "free", nitrogen, green plants cannot utilize it. As a matter of public economy, people have found it worth while to save the manure of barnyards and even the sewage of cities for the nitrogen com- pounds that these contain. But in spite of all our saving, vast quantities of nitrogen are washed out to sea or thrown into the air beyond the reach of our common plants. It has been possible to use nitrates, which are found as mineral deposits in certain places, especially in Germany and Chile. But the quantity of these nitrates is limited, and they are relatively expensive. On certain islands off the coast of South America there are extensive deposits of guano, or bird refuse, left there by countless birds that have built their nests upon these 150. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the or
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Keywords: ., book, bookcentury1900, booksubjectbiology, booksubjecthumanbeings
