Evoecotoxicology: Environmental Changes and Life Features Development duringthe Evolutionary Process—the Record of the Past at DevelopmentalStages of Living Organisms

Abstract

For most of evolutionary history, scientific understanding of the environment and life forms is extremely limited. In this commentary I discuss the hypothesis that ontogenetic features of living organisms can be considered biomarkers of coevolution between organisms and physicochemical agents during Earth’s history. I provide a new vision of evolution based on correlations between metabolic features and stage-dependent susceptibility of organisms to physicochemical agents with well-known environmental signatures. Thus, developmental features potentially reflect environmental changes during evolution. From this perspective, early multicellular life forms would have flourished in the anoxic Earth more than 2 billion years ago, which is at least 1.2 billion years in advance of available fossil evidence. The remarkable transition to aerobic metabolism in gastrula-stage embryos potentially reflects evolution toward tridermic organisms by 2 billion years ago. Noteworthy changes in embryonic resistance to physicochemical agents at different developmental stages that can be observed in living organisms potentially reflect the influence of environmental stress conditions during different periods of evolutionary history. Evoecotoxicology, as a multidisciplinary and transdisciplinary approach, can enhance our understanding of evolution, including the phylogenetic significance of differences in susceptibility/resistance to physicochemical agents in different organisms.

Stage‐dependent susceptibility to copper in Rhinella arenarum embryos and larvae

“…From this perspective, the ancestors of free-living organisms were exposed to harsh environmental conditions, including metal availability, as has been reported for the anoxic period in Earth history based on geochemical studies [39]. The initial anaerobic stages of R. arenarum embryos reflect the environmental conditions of these ancient times [38] and therefore could be associated with high resistance to metals and physical agents [12,20], including the results of the present study of Cu toxicity. The gradual increase in free oxygen from approximately 2.4 billion years ago onward may be reflected during ontogenesis by the gradual increase in oxygen consumption as the embryo develops [38].…”

“…The initial anaerobic stages of R. arenarum embryos reflect the environmental conditions of these ancient times [38] and therefore could be associated with high resistance to metals and physical agents [12,20], including the results of the present study of Cu toxicity. The gradual increase in free oxygen from approximately 2.4 billion years ago onward may be reflected during ontogenesis by the gradual increase in oxygen consumption as the embryo develops [38]. The associated increase in oxidative stress enhanced by transition metals such as Cu could explain the higher susceptibility to this chemical during organogenic stages.…”

“…In fact, living organisms at ontogenic stages could be considered as biomarkers of environmental signatures during the evolutionary process of their phylogenetic ancestors [38]. From this perspective, the ancestors of free-living organisms were exposed to harsh environmental conditions, including metal availability, as has been reported for the anoxic period in Earth history based on geochemical studies [39].…”

Nickel toxicity in embryos and larvae of the South American toad: Effects on cell differentiation, morphogenesis, and oxygen consumption

“…By considering ontogenic features such as stage-dependent biochemical or physiological features as well as stage-dependent susceptibility to noxious agents as biomarkers of the coevolution between the ancestors of living forms and environmental signatures during Earth's history [39], a new synthesis of the evolutionary process has been provided [13,39]. Does the stagedependent susceptibility to Ni reported in the present study reflect environmental changes during the evolutionary process?…”

Small is useful in endocrine disrupter assessment—four key recommendations for aquatic invertebrate research

“…A trans-disciplinary body of data is steadily developing under the title of ''systems biology'' (e.g. Andersen et al 2005;Latterich 2005) and ''evoecotoxicology'' (Herkovits 2006). From an applied aspect, for example in terms of OECD test guidelines, there is a clear international commitment to develop robust invertebrate chronic (most importantly, life cycle) test methods to assess the effects of potential endocrine disruptors.…”