The Gradient Theory
نویسنده
چکیده
The gradient theory [4] is recognized as Charles Manning Child?s most significant scientific contribution. Gradients brought together Child?s interest in development and his fascination with the origins of individuality and organization [5]. The theory grew from his studies of regeneration, which were largely based on work he conducted with invertebrates, such as planaria [6], a flat worm, and the hydroid Tubularia. Child observed that regeneration occurred in a graded process along the axis of the organism, with the characteristics of each physiological process seemingly determined by its location along the axis. To explain these observations, Child posited the existence of physiological factors working to guide the regenerative process. He was convinced that these differences along the gradients could be explained quantitatively.
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