CHAPTER XIV

THE INFLUENCE OF THE ENVIRONMENT AMONG ANIMALS AND PLANTS 325

(1) Observations show that environment and heredity are complementary one to the other. (2) Abnormal stimuli may produce almost any result, but (3) for each species there is a normal environment, to certain elements in which marked responses may be made, though (4) generally speaking sessile organisms are far more responsive to differences in the environment than are free-living organisms. (5) Among free-living species in a state of nature closely related to man, modifications are not of great importance in producing variations.