v^J^Other Modes of Nutrition; 

 Conservation of Food 

 Elements 



ALMOST all higher organisms are either 

 typical animals or typical plants; but among 

 lower organisms, the lines of distinction are 

 somewhat blurred. Some lower organisms, 

 are holophytic, some are holozoic, others are 

 more or less intermediate between the plants 

 and the animals, and still others are quite 

 different, in their mode of nutrition, from 

 either plants or animals. 



THE FUNGI 



The fungi are a large group (about 75,000 

 species) of relatively simple plants that do 

 not possess chlorophyll and that lack a ca- 

 pacity to ingest food. Many fungi closely 

 resemble the algae in general structure and 

 reproductive habits, and consequently they 

 are classified as plants, despite the lack of 

 chlorophyll. 



Many fungi, including the bacteria (Fig. 

 10-1) and yeasts (Fig. 10-2), are unicellular; 



but others, including the molds, mildews, 

 rusts, smuts, puffballs, and mushrooms, are 



more complex in structure. The body, or 

 mycelium, of a complex fungus consists of a 

 mass of long, slender, much-branched 

 threads, called hyphae. In some species the 



% cP 



Fig. 10-1. The bacteria are extremely small fungus 

 plants, which display three general forms. The spheri- 

 cal forms are cocci; the rod-shaped forms, bacilli; and 

 the spiral forms, spirilla. Colonial aggregates of bac- 

 teria are designated by special names; e.g., staphylo- 

 coccus, for irregular bunches of cocci, like those on the 

 left; and streptococcus, and streptobacillus, for the 

 chainlike colonies of cocci and bacilli (shown at the 

 center). 



173 



