In animals and humans, genes determine the general size and shape of the organism, butthere may also be variation in physical characteristics due to environmental inﬂuences. Allorganisms function most efficiently under certain environmental conditions; however, anindividual organism may react to some change in the environment with responses that changethe form or internal structure of the body.
An organism’s environment includes nonliving factors such as temperature, water, andnutrients. The environment also includes biological factors: all the other organisms that arepart of any individual’s environment. Environmental stimuli can have important effects onindividual organisms, groups, and whole populations.
The inﬂuence of environmental factors is particularly effective during the formativestages of life, both before and after birth. The experiences of early life determine the physicaland mental attributes of the young and thereby determine the characteristics of the adult. Early influences can have favorable or unfavorable effects on the young organisms development. Environmental factors exert such a strong inﬂuence on development that some physical or mental characteristics are difficult or impossible to change later in life.
Research on many types of animals and observations of human life have revealed thatearly environmental inﬂuences affect an individual initial rate of growth and resistance tovarious types of stress, as well as the ultimate body size of the adult. Environmental factorsalso affect learning ability and behavioral patterns in the young.
Summarize the points made in the lecture, being sure to explain how they support specific points made in the reading passage.