Global Marine Species Similarity Linked to Post-Extinction Environment

Environmental Changes After Mass Extinction Led to Global Species Similarity, Study Finds

A new study published in the journal Science Advances offers insights into how environmental factors shaped the recovery of life following the Earth’s largest extinction event, the Permian-Triassic extinction, also known as the Great Dying. Occurring approximately 252 million years ago, the extinction wiped out nearly 80–90% of marine species and about 70% of land-based vertebrate families. In the aftermath, fossil records show that many of the surviving species appeared to be remarkably similar, even across vastly different regions of the globe.

The research suggests that this global similarity among post-extinction species was not primarily due to ecological interactions but rather to widespread environmental changes. Conducted by a team of scientists from Stanford University and other institutions, the study focused on marine organisms such as clams, oysters, and snails, which were among the groups that survived the extinction event.

According to the findings, two major factors contributed to the phenomenon of species homogenization across the planet.

First, the extinction led to ecological release, a process where the disappearance of major predators or competitors allowed surviving species to expand their geographic range and population sizes without constraint. In the absence of dominant species, those that remained were able to spread into new environments and niches that were previously inaccessible to them.

Second, physiological adaptability played a key role. The surviving species were more capable of coping with the new, harsher environmental conditions created by the extinction event, including changes in ocean chemistry, temperature, and oxygen levels. This adaptability allowed them to survive and thrive in different parts of the world, leading to a consistent appearance of similar species across diverse habitats.

The study explains that the dramatic environmental shifts following the Great Dying created a narrow set of conditions in which only certain species could survive. As a result, those that had the physiological traits to tolerate these stressful conditions spread widely, replacing the diverse ecosystems that had existed before the extinction.

This pattern of biological homogenization is evident in the fossil record and shows that in times of global environmental stress, life tends to reorganize around a smaller number of broadly adaptable species. These findings help scientists understand how life rebounded after the Earth’s most severe extinction and shed light on the mechanisms that can drive global ecological uniformity.

By analyzing fossil distributions and environmental conditions, the research offers a clearer understanding of how life recovers following massive disruptions. The implications are significant for modern biodiversity and climate change, as they suggest that in the face of global environmental stress, species that can quickly adapt may dominate, potentially leading to a reduction in global biodiversity.The researchers emphasize that such findings are not only important for understanding Earth’s past but also offer a lens through which we can evaluate present-day biodiversity loss and the possible future of life on Earth amid ongoing environmental change.The study, titled Environmental controls on taxonomic and functional similarity across space in post-extinction marine communities, was published in Science Advances and includes contributions from multiple researchers in the field of Earth and planetary sciences.

Source: DownToEarth Magazine