Chap. 5 



ANIMALS AND THEIR ENVIRONMENTS 



73 



Fig. 5.7. Types of marine plankton, the great population of minute plants and 

 animals that live in the surface of the seas and includes the eggs and developing 

 young of the majority of marine animals. Top, the larva of the porcelain crab 

 like other plankton organisms is translucent and bears outgrowths that serve as 

 floats characteristic of animals of the plankton. (Photograph by D. P. Wilson, 

 Marine Biological Lab., Plymouth, England.) Bottom, the protozoan, Globigerina 

 biilloides. Enormous numbers of these live among the plankton in the surface 

 waters of the sea. Their chalky frames and fine spines dropping through the water 

 for millions of years have formed the globigerina ooze of many parts of the ocean 

 bottom. (After Murray and Hjort. Courtesy, Coker: This Great and Wide Sea. 

 Chapel Hill, N.C., Univ. of N. Carolina Press, 1947.) 



practically all the energy on earth, excepting atomic energy. It is the prime 

 mover of the winds because it heats different places unevenly and this sets 

 currents of air in motion. As heat it lifts water by evaporation eventually to 

 form clouds and be distributed in rain. With its energy plants make the food 

 for which directly or indirectly all animals including man struggle unceasingly. 



