Biochemical and ecological similarities in marsh plants and diving animals

Higher plants which can survive flooding have certain ecological and biochemical similarities with diving reptiles, birds, and mammals. The ecological similarities arise from the fact that these wet-land plants and diving animals are all terrestrial organisms which have re-entered the aquatic habitat as a retreat or ecological refuge free from interference by dry-land species. To survive in the wet-land or aquatic habitat species of terrestrial origin have to restrict their metabolic rate in the absence of oxygen and exploit a wide range of metabolic products to aid proton disposal and avoid the dangers of cell toxicity due to the accumulation of an excessive oxygen debt. In some plants metabolic adaptation to anoxia (low oxygen supply) resembles that found in animal parasites. It is a striking example of metabolic co-evolution that the retreat of so many terrestrial species of both plants and animals back to the low-oxygen habitat has been made possible by the exploitation of similar biochemical control mechanisms and pathways.