One of the most mind-blowing and controversial Earth science concepts has to be the Gaia hypothesis. The idea was first introduced in the 1970s by chemist James Lovelock and microbiologist Lynn Margulis.
It states that Earth and its biological systems work together as one to maintain conditions for life and keep the planet turning.
But some experts have noticed interactions on Earth that are in direct opposition of the Gaia hypothesis. Some large-scale planetary disruptions, such as climate change and an overuse of resources, can eradicate the progress of the world. This suggests that life worsens conditions for itself or is even self-destructive.
A new study argues that Gaian systems actually employ large-scale disruptions as part of a way to self-perpetuate the conditions for life on Earth. Eventually, the findings could help scientists in their search for life beyond our home planet.
Historically, Earth has behaved like a Gaian system. Some of the complexities of life on Earth seem to have arisen from large-scale disruption events.
For instance, the Great Oxidation Event was a period when oxygen levels in Earth's atmosphere increased drastically about 2.5 billion years ago. Most anaerobic life was killed, but it paved the way for animals to evolve.
The research team conducted computer modeling experiments to test how groups of species might've evolved. In one of the computer models, the Tangled Nature Model, the fate of each species is connected to one another.
The researchers simulated disruptions to modeled worlds by temporarily reducing the carrying capacities. They applied numerous perturbations of different lengths.
After thousands of simulations, the team found that a perturbed system was more likely to wipe out life, but perturbed systems in which life has managed to survive had greater diversity and an abundance of life that persisted over many, many generations.
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Overall, a system collapse provides the opportunity for new life to thrive. The more complex a planet's living system is, the more complex species' interactions are. Therefore, they concluded that life is not self-destructive.
Peter Ward, a paleontologist at the University of Washington who was not involved in the study, was one of the first scientists to argue that life on Earth may be self-destructive.
The idea was called the Medea hypothesis. He is not convinced by the new study because life has always been a major cause of mass death throughout Earth's history. Huge disruption events make conditions worse.
The results of the study could aid scientists in their search for extraterrestrial life by narrowing down which planets in the universe have the highest chance of containing life. Further research is needed to identify the planets.