434 



INDEX 



Seeds, 183, 190, 191 



evolution of, 101 

 Segmentation, of animals, 104, 224, 229 

 Seifs, 55, 56 

 Selachii, 273, 274-275 

 Selaginellaies, 167,175,176,363 

 Semidesert plants, 188 

 Senescence, of species, 340 

 Sense, homing, 294-295 

 Sepals, 190 



Serai stages (see also Biogeographicai dy- 

 namics), 359, 369 

 Seres, 360-362 



Serpent stars, see Ophiuroidea 

 Serpentes, 235, 281, 282, 285, 287-288, 316 

 Setae, 224 

 Sexuality (see also Hermaphroditism; 



Parthenogenesis), 88 

 Sharks, see Squaloidea 

 Shells (see also Exoskeleton), bivalved, 215, 

 220, 237, 238 



butterfly, 217 



coat-ol-mail, see Amphineura 



cup-and-saucer, see Gastropoda 



lamp, see Brachiopoda 



slipper, see Gastropoda 



tooth or tusk, see Scaphopoda 



of turtles, 285 

 Shipworms, 221 

 Shorelines, 53-55 



beaches of, 40 



compound, 55 



currents of, 35, 36 



deposits of, 35-36 



of emergence, 53-54 



fiord, 54 



mature profile of, 53, 54, 55 



ria, 54 



of submergence, 54-55, 58 



succession along, 314-315 



uplifting and depressing of, 61 

 Shrimp, brine, see Anostraca 



clam, see Conchostraca 



claw, see Conchostraca 



fairy, see Anostraca 



malacostracan, 213, 238, 239 



mantis, see Stomatopoda 



opossum, 239 



tadpole, see Notostraca 



true, see Decapoda 

 Shrubs, 101 



Sideswimmers, see .'\mphipoda 

 Sills, 58-59 

 Silt, 77 



Silurian Period, 1 12 

 Siphonaptera, 200, 252, 334, 349 

 Sipunculoidea, 211, 213, 216-217,223 

 Sirens, jwTrachystomata 

 Skates, see Batoidea 

 Skeleton, external, 229, 230, 231, 236, 285 



internal, 256, 263, 266 

 Skippers, see Lepidoptera 

 Sky colors, 12 



Slime molds, see Myxomycophyta 

 Slopes (see also Topography), as ecological 

 factor, 328, 332, 354, 360 



erosion of, 42 

 Slugs, see Gastropoda 



Smog, 1 1 



Smuts, 141 



Snails, see Gastropoda 



Snakeflies, see Neuroptera 



Snakes, see Serpentes 



Snow, 49 



elTect on: migration, 344, 345; tempera- 

 ture, 304 



influenced by winds, 324 



organisms of, see Glaciers 



red, 150 

 Social behavior, 348-349 

 Social dominance, 335, 348-349 

 Social insects, 243, 246, 252, 338 

 Societies, 348-349 



layer, 359 

 Soils, 75-82, 327-330 



air stagnation in, 323, 324 



alkalinity of, 329 



animals of, 229, 243, 329-330, 353 



in atmospheric cycle, 1 1 



azonal, 79, 82 



classification of, 77-82 



dry, plants of, 310 



as ecological factor, 327-330, 354 



effect on: climaxes, 360; stream erosion, 

 42; temperature, 304, 305 



erosion of, 77 



fertility and, 327 



formation of, 75-76, 79,81 



gravelly nature of, 77 



horizons of, 76 



influenced by fire, 330 



intrazonal, 79, 81 



kinds of, 79 



moist, 310, 320, 321,322 



morphogenic regions and, 66, 67 



natural classification of, 77-82 



organisms of, 130, 140, 229, 243, 310, 

 329-330, 353 



profile of, 76 



reaction of, 328 



salinity of, 328-329 



texture of, 77, 78, 327 



topography and, 332 



water availability in, 308, 327, 328 



zonal, 79, 81 

 Solar radiation (see also Light), in alpine 

 areas, 324 



angle of, 7, 12-13, 305 



earth's absorption of, 8, 25 



as ecological factor, see Light 



effect on: auroras, 12; climate, 25; life, 

 7-8; ocean currents, 31 ; seasons, 7, 

 12-13 



as heat source, 12 



physical aspects of, 7-8 

 Solar system, 1, 6 

 Solifugae, see Solpugida 

 Solpugida, 233,234,329 

 Somites, 224 

 Sori, fern, 179, 180 

 Sowbugs, see Isopoda 

 Spacing of life, 347-349 

 Spatial relations, population, 342-349 

 Specializations, 84 



Speciation (see also Biogeographicai dy- 

 namics), 118,335,338,355 



Species, 95-96, 118 

 Sperm, see Gametes 

 Spermatophytes, 167, 172, 182-191 



gametophytes of, 167-168 



spores of, 167-168 

 Sphagnales, 162, 163, 164, 321 

 Sphenopsida, 151, 165, 166, 167, 172, 174, 



176-178, 369 

 Spicules, sponge, 194, 195, 196 

 Spiders, sea, 231 



sun, see Solpugida 



true, see Araneae 

 Spike mosses, see Selaginellaies 

 Spine, leaf, 172 

 Spinnerets, 234 



Spiny anteaters, see Prototheria 

 Spiny-skinned animals, see Echinodermata 

 Spiracle, 270, 273, 274, 277, 278 

 Sponges (see also Porifera), calcareous, see 

 Calcarea 



frame, see Demospongia 



glass, see Hexactinellida 

 Spongin, 195, 196 



Sporangia, 137, 138, 140, 141, 151, 152, 

 156, 157, 159, 160, 163, 164, 168, 173, 

 174, 177, 179, 183, 185, 186, 188, 190, 

 191 

 Spores (see also Ike Glossary), 87, 89 



asexual, absent in Tracheophyta, 155 



swarm, 137 



of Tracheophyta, 167-168 

 Sporocarp, fern, 179 

 Sporophytes, alternation of generations 

 and, 87, 88 



of Angiospermae, 189-191 



of Bryophyta, 156 



in diplobiontic life cycle, 89 



of Embryophyta, 156 



evolution of, 100-101 



of Lycopsida, 174-175 



origin of, 100 



of Psilopsida, -173-174 



of Pteropsida, 179 



of Sphenopsida, 177-178 



of Tracheophyta, 167-172 

 Sporozoa, 135 

 Sporulation, 87, 89 

 Spring overturn, of lakes, 317, 318 

 Springtails, see Collembola- 

 Squalls, 23 

 Squaloidea, 273, 275 

 Squamata, 284, 285, 286-288 

 Squids, see Cephalopoda 

 Stability, 401 

 Stage, perfect, 139 

 Stalactites, 42 

 Stalagmites, 42 

 Stalk, Bryophyta, 156, 157, 159, 161, 163, 



164 

 Stamens, 188, 190, 191 

 Stand, 352, 390 

 Star system, 1 

 Starfish, see Asteroidea 

 Stars, celestial, 1, 2, 3, 5 



migration by, 346 

 Stars, organismal, basket, see Ophiuroidea 



brittle, see Ophiuroidea 



feather, see Crinoidea 



