The Negligible Senescence of Sea Urchins

Aging as we understand it is almost a universal phenomenon in animals. Clearly there is something advantageous in evolutionary terms in having disposable individuals carry the immortal germline forward in time. One possibility is that aging is an emergent property of the fact that selection pressure is always going to fall more heavily on younger individuals, and thus evolution favors change in the direction of biological systems that are highly effective in youth but fall apart later on. Resources directed towards long-term maintenance subtract from resources directed towards immediate reproductive success. It is a brutal zero-sum race to the bottom, driven by the mortality of predation and a hostile environment. Younger individuals contribute more to the fitness of a species, because fewer of them have been eaten or otherwise removed from the picture. Another view is that immortal species do have certain advantages in certain situations, and will emerge over time in any period of stability. They will vanish in eras of environmental change or hardship, however, outcompeted by species that age, as aging makes them more likely to adapt successfully. This viewpoint predicts the present situation, in which there exist only a very few species that appear not to age (as for hydra), or to age negligibly to various degrees (lobsters, sea urchins, naked mole-rats, and so forth). But at root, these evolutionary theories are all based on models and hypotheses, and thus prone to ...
Source: Fight Aging! - Category: Research Authors: Tags: Medicine, Biotech, Research Source Type: blogs