Skip to main content Accessibility help
×
Home
  • Print publication year: 2021
  • Online publication date: April 2021

5 - Developmental Sequences: Sustainability versus Adaptation

Summary

Many objections can be raised against the usual description of development as the series of changes between egg (or seed) and adult. First, an individual’s development does not necessarily begin with an egg or a seed: examples are hydra polyps produced by budding, or new plants produced by cuttings. Second, not all animals and plants reproduce as adults. Third, development does not necessarily start from scratch with the new generation. Fourth, the egg is not the least specialized of cells. In a revised concept of development there is space for regeneration too. There is no reason to consider regeneration as the expression of a hidden finalism intrinsic to living matter. Instead, regeneration is the reactivation – induced by injury or physiological loss of a body part, as in the shedding of deer antlers – of a proliferative and morphogenetic activity broadly comparable to embryonic development or to asexual reproduction by fragmentation, and is not necessarily adaptive. Development is not always a sustainably adaptive process. Tumour growth, for example, is a developmental process, albeit tragically maladaptive for the organism in which it occurs.