Artificial intelligence finds surprising patterns in Earth's biological mass extinctions

"There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, endless forms most beautiful and most wonderful have been, and are being, evolved," concludes Charles Darwin's seminal work "On the Origin of the Species." Actually, the majority of species that have ever lived are now known to be extinct by biologists.

Throughout Earth's history, the extinction of certain species has generally been approximately balanced by the emergence of new ones, with a few significant, brief imbalances known to scientists as mass extinction events. It has long been accepted by scientists that large-scale extinctions trigger "radiations," or fruitful times for species evolution—a concept known as "creative destruction." Scientists at the Tokyo Institute of Technology's Earth-Life Science Institute (ELSI) led a recent study that used machine learning to look at the co-occurrence of fossil species. They discovered that while radiations and extinctions are rarely related, mass extinctions most likely don't cause radiations on a similar scale.

A fundamental idea in traditional theories of evolution is creative destruction. It becomes evident that there are times when a large number of species abruptly vanish and a large number of new species emerge. Nonetheless, compared to extinction events, radiations of a similar size to the mass extinctions—referred to as the mass radiations in this study—have gotten significantly less attention. In this study, the effects of radiation and extinction were compared during the so-called Phanerozoic Eon, the time span for which fossils are accessible. Palaeontologists see significance in the Phanerozoic, which is named from the Greek word for "apparent life" and spans the most recent ~ 550 million years of Earth's ~4.5 billion-year history: It is difficult to see the previous evolutionary record since the majority of species that lived before this time were microorganisms that were difficult to produce fossils. According to the new study, many of the most remarkable periods of evolutionary radiation occurred when life entered new evolutionary and ecological arenas, such as during the Cambrian explosion of animal diversity and the Carboniferous expansion of forest biomes. This suggests that creative destruction isn't a good description of how species originated or went extinct during the Phanerozoic. It is unknown if this is true over the previous ~ 3 billion years during which bacteria dominated the environment because there is not much information on such ancient diversity that has been documented to support a similar study.

A few of the worst mass extinction events in the Phanerozoic fossil record have been recognized by paleontologists. These mostly include of the "Big Five" mass extinctions, such the end-Permian mass extinction, which is thought to have claimed the lives of over 70% of all species. Scientists believe that human activities, particularly hunting and changes in land use brought about by the growth of agriculture, is the primary cause of the sixth mass extinction that may be upon us.

The extinction of the non-avian dinosaurs, known as the Cretaceous-Tertiary extinction (sometimes shortened to "K-T," after the German spelling of the term), is a well-known example of the preceding "Big Five" mass extinctions. It is thought to have been triggered by a meteor strike that occurred around 65 million years ago. Based on the fossil record, scientists have concluded that particularly fruitful radiations are produced after catastrophic extinction events. For instance, it is commonly believed that in the K-T dinosaur-erasing event, a wasteland was left behind, allowing creatures such as mammals to recolonize and "radiate," leading to the evolution of numerous new mammal species and, eventually, the emergence of humans. In other words, maybe we wouldn't be here talking about this issue if the K-T event of "creative destruction" hadn't happened.

In ELSI's "Agora," a spacious common area where scientists and guests frequently have lunch and pick up new discussions, the new research began with a casual talk. The authors of the paper, Jennifer Hoyal Cuthill, an evolutionary biologist and research fellow at Essex University in the United Kingdom, and Nicholas Guttenberg, a physicist and machine learning specialist and current research scientist at Cross Labs collaborating with GoodAI in the Czech Republic, were both post-doctoral scholars at ELSI when the work started. They were discussing whether or not machine learning could be used to visualize and comprehend the fossil record.

Before the COVID-19 pandemic started to limit international travel, they visited ELSI and worked assiduously to expand their study to investigate the relationship between radiation occurrences and extinction. By these talks, they were able to connect their new findings to the range of theories already in existence about radiation and catastrophic extinctions. They soon discovered that the evolutionary patterns that machine learning had helped them identify were fundamentally different from conventional interpretations.

The researchers examined over 1 million records in a large, carefully maintained public database that included almost 200,000 species, using a unique application of machine learning to investigate the temporal co-occurrence of species in the Phanerozoic fossil record.

"Some of the most challenging aspects of understanding the history of life are the enormous timescales and numbers of species involved," stated Dr. Hoyal Cuthill, the lead author. Through the visualization of this data in a way that is legible by humans, new machine learning applications can be beneficial. This implies that we may literally hold 500,000 years of evolution in the palm of our hands and learn new things from what we observe."

Using their objective methods, they discovered that 15 mass radiations, two combined mass extinction-radiation events, and the "big five" mass extinction events that had previously been identified by palaeontologists were all included in the top 5% of significant disruptions in which extinction outpaced radiation or vice versa. Interestingly, our investigation discovered that the most similar mass radiations and extinctions were extremely rarely paired in time, denying the concept of a causal linkage between them. our is in contrast to earlier narratives that emphasised the relevance of post-extinction radiations.

"The ecosystem is dynamic; you don't necessarily have to chip off an existing piece to allow something new to appear," co-author Dr. Nicholas Guttenberg remarked.

The group also discovered that radiations might, in fact, significantly alter already-existing ecosystems—a concept the authors refer to as "destructive creation." They discovered that, on average, 19 million years after the Phanerozoic Eon, nearly every species that comprised an ecosystem at that point had vanished. On the other hand, this turnover rate is substantially larger during major extinctions or radiations.

This provides a fresh viewpoint on the processes driving the current sixth extinction. Since the Quaternary epoch began 2.5 million years ago, there have been numerous climatic changes, including abrupt shifts in the amount of glacier cover in high-latitude areas of the planet. This indicates that the already fragmented biodiversity is being further eroded by the current sixth extinction, and the scientists predict it will take a minimum of 8 million years for the biodiversity to return to the long-term average of 19 million years. It is more difficult for the typical process of new species origination to replace what is being lost when a species that may have lived for millions of years is erased by an extinction that occurs under our watch, according to Dr. Hoyal Cuthill.