THi: INTEHDKPKNDKNCE OF I.IVINC T|||\,;s ;,.•, 



roverod witli the dead bodi(>s of plants and animals. TUr i)acteriu of 

 decay are very numerous in rich, damp soils containing large amounts 

 of organic material. They decompose organic materials, changing 

 them to compounds that can be absorbed by plants to be used ii, 

 building protoplasm. Without decay life would be impossible. f„r 

 green plants would otherwise be unable to get the raw food materials 

 to make food and living matter. 



In general all plants, both colorless and green, may be said to play 

 a part in ridding the earth of organic wastes. The fungi, or colorless 

 plants, get their nourishment from the dead bodies of plants and 

 animals, while the green plants take organic wastes from the soil 

 to be used in the manufacture of foods. 



Many animals also take part in scavenging. Some of the food of the 

 protozoa is made up of decaying unicellular material and the bacteria 

 which cause its decay. Certain forms, especially insects, feed upon and 

 lay their eggs in decaying flesh, while myriads of insects and their 

 larvae help to break down decaying wood in a forest. These are 

 only a few instances of this important function. 



Food-getting in Plants 



Although green plants make foods and use raw food materials ' from 

 their environment to do this, there are some that destroy foods. 

 Fungi, such as bacteria, molds, smuts, and rusts, ruin billions of dollars' 

 worth of food plants and plant jiroducts each year. This is seen in 

 damage to crops, fruits, stored foods, and animals used as food by 

 man. 



Carnivorous Plants 



A curious exception to ordinary green plant nutrition exists in 

 carnivorous plants, which also illustrates a different interrelationshij) 

 between plants and animals. Carnivorous plants add to their nitro- 

 gen requirement in several ways. The fresh-water aquatic plants 

 known as bladderworts {Utricidaria) catch water fleius and other 

 small crustaceans in hving bladderlike traps. Just what lure urges 

 the crustaceans to destruction is hard to say, but the fact that they 

 are caught in numbers is verified by their decomposed remains found 

 in the bladders. Other animal-eating forms are the various pitch(>r 

 plants (Sarracema sp.), some of which are found in our northern 

 swamps. Insects are apparently lured to the urn-shaped leave^' 



> See pages 253-262. 



