Mechanisms and evolution of resistance to environmental extremes in animals

Thomas C Boothby

doi:10.1186/s13227-019-0143-4

Abstract

When animals are exposed to an extreme environmental stress, one of three possible outcomes takes place: the animal dies, the animal avoids the environmental stress and survives, or the animal tolerates the environmental stress and survives. This review is concerned with the third possibility, and will look at mechanisms that rare animals use to survive extreme environmental stresses including freezing, desiccation, intense heat, irradiation, and low-oxygen conditions (hypoxia). In addition, an increasing understanding of the molecular mechanisms involved in environmental stress tolerance allows us to speculate on how these tolerances arose. Uncovering the mechanisms of extreme environmental stress tolerance and how they evolve has broad implications for our understanding of the evolution of early life on this planet, colonization of new environments, and the search for novel forms of life both on Earth and elsewhere, as well as a number of agricultural and health-related applications.

Highlights

The history of life on Earth has been one of adaption and evolution to new and changing environments
Rather than being an exhaustive review on the subject, this review serves as an introduction to five different abiotic stresses as well as extremotolerant animals that have evolved to cope with these stresses
Tardigrades are a group of microscopic animals renowned for their ability to survive a number of environmental extremes including desiccation [38], freezing [39], intense radiation [40], extreme pressures [41], and temperatures up for 151 °C [42]

Summary

Introduction

The history of life on Earth has been one of adaption and evolution to new and changing environments. To reduce ATP demand, hypoxia-tolerant organisms are thought to suppress two major cellular processes: protein synthesis and membrane ion-pumping—though other mechanisms clearly contribute to some degree to a decrease in ATP consumption [5, 6]. The combination of defense and rescue mechanisms leads to a lowered, but balanced, ATP supply and demand and the survival of the hypoxia-tolerant animal.

Results

Conclusion