to form simple amino acids; (3) the precipitation of colloidal substances in a solution containing metal salts, such as those of phosphoric acid, and resulting combinations; (4) coagulations, resolutions, and aggregations of particles; and (5) "the formation, through the chemical activity of these bioblasts, of an enclosing membrane, resulting in the first living 'cells'." Crile, Glasser, Telkes, & Rowland (1932) emphasize the formation and activities of nitrocarbons as a primary quality of life. Gulick (1948) gives evidence from the point of view of a biochemist that supports his belief that life originated in the sea. The Original Home of Life 7 living matter came into existence many times, probably always in the sea where there was appropriate temperature and when the sea water was more dilute than now. Allen (1923) also maintains that life arose in the sea and stresses the importance of photocatalysts acting on water, carbon dioxide, and simple compounds of nitrogen. Richardson (1928) pictures the origin of life in tropical intertidal pools along rocky seashores, and emphasizes colloids and pigments as factors. Flattely & Walton (1922) say "the shore has strong claims to be recognized as the birthplace of life," and cite the littoral region as "the cradle of evolution." Woodruff (Barrell et al., 1924) has reviewed various theories of the origin of life. The Sea as the Original Home of Life In the oldest strata of sedimentary rocks which contain fossils the remains of plants and animals all appear to be marine. This indicates that life immediately before that time probably existed largely or wholly in the ocean. This of course does not preclude the possibility that life previously existed on land or in fresh water and became extinct without leaving records as fossils. However, "at the very begining of the Paleozoic Era are found all of the main kinds of marine animals other than fishes" (Schuchert, in Barrell et al., 1924). The invertebrates had been in existence during the preceding eras (Archeozoic, Proterozoic) long enough for the chief types as they exist at present to become established. As time went on many of the older types (trilobites, etc.) became completely extinct and new types (chordates, etc.) came into existence. As evolution progressed, certain animals that were related to early chordates (ostracoderms, arthrodires, etc.) and some that were clearly chordate (cyclostomes, elasmobranchs) appeared in the ocean, but most of them and the bony fishes apparently had their origin in fresh water
