xii Contents 



Hydrogen Ion Concentration 268 



Calcium Carbonate 270 



Chapter 8 ■ NUTRIENTS 277 



Nutrients and the Environment 277 



Modes of Nutrition 278 



Influence of Nutrients on Green Plants 280 



Nutrients Required 280 



Law of the Minimum 281 



Limitation by Nutrients in Nature 283 



Influence of Nutrients on Animals 292 



Decomposition and Regeneration 297 



Processes of Decomposition and Transformation 298 



Place of Decomposition 300 



Stagnation in Cycles 303 



Regeneration 304 



Rate of Regeneration 305 



Ratio of Regenerated Materials 306 



Chapter 9 • RELATIONS WITHIN THE SPECIES 309 



Origin of Groups 309 



Reproduction 309 



Passive Transport 311 



Active Locomotion 312 



Common Orientation 312 



Mutual Attraction 314 



Effects of Increased Numbers 316 



Harmful Effects 317 



Beneficial Effects 322 



Protection 322 



Influence on Reproduction 323 



Division of Labor 327 



Population Development 333 



Natality and Mortality 333 



Biotic Potential and Environmental Resistance 334 



Form of Population Growth 336 



Logistic Curve 337 



Equilibrium and Fluctuation 340 



Optimal Yield 344 



Spatial Relations of Populations 348 



Space Requirements 348 



Home range and Territory 350 



Homing 353 



Return Migration 355 



Emigration 357 



Chapter 10 ■ RELATIONS BETWEEN SPECIES 362 



Symbiosis 364 



Mutuahsm 364 



Mutualism with Continuous Contact 364 



Mutualism without Continuous Contact 370 



