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Saturday, January 29, 2011

Evolution: Study shows why rapid development not likely an advantage, study shows

Spotted salamander, Camazine
Recent studies of evolution, such as Lenski's, have focused on bacteria because they replicate quickly. These findings offer insight into at least one reason why quick development would not benefit most life forms, suggesting time constraints on how rapid evolution could be.

"Faster Early Development Might Have Its Costs, Study in Salamanders Suggests"(ScienceDaily, Jan. 25, 2011), researchers found recently:
Fast development is often perceived as an advantage, as it enables better harmony with one's environment and readiness to cope with the challenges that it poses. However, research conducted at the University of Haifa, Israel, and University of California, Santa Cruz, and published in the scientific journal PLoS ONE, found that the acceleration of developmental rate incurs potentially lethal physiological costs for the developing individual. "Our findings are consistent with research findings on other animals and call for further research on rates of development in humans," said Asaf Sadeh who led the study.

[ ... ]

... accelerated development carries costs: larvae that developed more quickly suffered greater rates of mortality. Larvae that falsely perceived the pond environment as long-lasting, and thus started life with a slow developmental rate, but then realized their misperception and compensated with significant acceleration, suffered the greatest rates of mortality. The physiological mechanisms underlying these costs are unknown, but are thought to involve both cellular causes such as oxidative damage from increased metabolic rates, and tissue-level causes such as overexploitation of undifferentiated stem cells or disrupted balance between the differentiation and growth of different tissues in the body. These physiological costs may also lead to increased vulnerability to environmental stresses other than drying, such as heat, disease and parasites, and might result in death.
It almost sounds as though they should be talking about "pysychological" development, but how the salamander "knows" all this is a puzzle for another day.


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