It’s easy to forget that, despite life having existed on Earth for billions of years and despite our relatively carefree existence from total destruction, throughout history there have been events that wiped out nearly everything! Fortunately for many life forms, they have the ability to go dormant and enter a state of reversible, reduced metabolic activity. In this state they are protected from decay and can survive long harsh periods where life would otherwise not survive. Is it just possible therefore that dormancy could also allow life to survive on other worlds like Mars or Venus?
‘Life, don’t talk to me about life,’ were the utterances of Marvin the depressive robot on the Hitchhikers Guide to the Galaxy. Unlike Marvin, it seems humanity loves talking about and exploring the possibilities that life may exist elsewhere in the universe. A discussion about life is always tricky though as life could, conceivably come in such a strange form that we might not even recognise it as life. Typically if we talk about searching for alien life of any level of existence, we tend to consider life like that which we find here on planet Earth. After all, we have to start somewhere.
Exploring the diversity of life on Earth gives us an insight into what critters might be out there in similar environments. One such state that is surprisingly common across Earthly organisms is the ability to enter the state known as dormancy. The process protects an inactive organism and minimises the chances of extinction by preserving the critical bodily functions and shutting down all others, but just temporarily. In a paper recently published in The Royal Society Journals, Kevin D. Webster and Jay T. Lennon explore dormancy theory in consideration of its enabling life to flourish elsewhere in the cosmos.
The duo first analysed the key activities that led to the evolution of intelligent life; the supply of chemical building blocks at the necessary rate to exceeded their decay and that some sort of compartmentalisation was needed for early primative life to offer protection between their cellular components and the environment. The sustained evolution of life from these early stages was susceptible to chance events but also error in DNA replications that may have brought a species to an evolutionary dead end.
Despite the sequence of events that brought about evolution that shaped our history there were events that momentarily brought a pause to proceedings. There have been five extinction events since the formation of Earth and it is the ability to drive through these dark days that dormancy really comes into its own.
Dormancy is a state of reduced activity or metabolism that organisms enter to survive during periods of challenging environmental conditions, such as extreme temperatures or reduced levels of light. This survival mechanism is common in plants, seeds, and certain animals, enabling them to withstand harsh seasons or environments. For animals, dormancy may take the form of hibernation or estivation, where metabolic rates decrease to conserve energy until conditions improve.
Dormancy provides protection, allowing inactive organisms to survive during unfavourable conditions and resume activity once more better conditions return. It may not have just helped organisms to survive harsh seasons but may have protected life from extinction during catastrophic events. It seems that the ability for primitive organisms to evolve dormancy processes is quite simple. If this is the case then it is quite plausible that any organisms that evolved on other planets with less than favourable conditions could be in their dormant state and waiting for conditions to improve.
Source : Dormancy in the origin, evolution and persistence of life on Earth