EVOECOTOXICOLOGY#: LIVING ORGANISMS AS BIOMARKERS OF THE COEVOLUTION WITH ENVIRONMENTAL AGENTS DURING THE EVOLUTIONARY PROCESS

JORGE HERKOVITS

Baltimore, Maryland

Congreso; XXVI Annual meeting SETAC N. A.; 2005

Setac N. A.

Life forms interacted with changing environmental conditions during almost 4,000 million years. For most of the evolutionary process our understanding of both the environment and life forms is extremely limited and controversial. This article focuses on the hypothesis that living organisms (mainly) at developmental stages could be considered as biomarkers of the coevolution of life forms and environmental features during the evolutionary process. In this context   the  (almost) anaerobic metabolism at blastula stage embryo could reflect the existence of multicellular organisms in the deep anoxic Earth while the transition to aerobic metabolism at gastrula could be related to the rise in free O2 around 2 billion years ago and the evolution towards tridermic organisms. Complementarily the high resistance to physico chemical agents at early developmental stages could reflect that living organisms had to cope with very adverse environmental conditions during the initial  2 billion years (including UV-B irradiation) while the high susceptibility at developmental stages with complex cell differentiation and morphogenetic processes (e.g. organogenesis and metamorphosis) contribute to the vision that those cell activities were achieved in times of low environmental stress conditions. Taking into account that also mass extinction events could be associated to chemical bomb scenarios (Herkovits 2001), the resistance at developmental stages to physico chemical agents could contribute to the understanding of the environmental stress supported by any specie during its phylogenesis.  Evoecotoxicology by considering living organisms as biomarkers of the interactions with chemical and physical agents during the evolutionary process could contribute to a better understanding of the evolutionary process in the Earth.