Scientists raise alarm about human-driven extinction threat to 'Tree of Life' branches

Scientists have issued a stark warning and said that humans are causing the disappearance of entire branches of the "Tree of Life," a classification system for all living things. 

The alarming revelation comes as a new study, published in the Proceedings of the National Academy of Sciences, highlights the impending threat of a potential sixth mass extinction event.

Professor Gerardo Ceballos, co-author of the study from the National Autonomous University of Mexico, asserts that the extinction crisis is on par with the climate change crisis but has not received the recognition it deserves. He emphasises that the future of mankind hangs in the balance.

What sets this study apart is its focus on the extinction of entire genera, which lie between the rank of species and family in the classification of living beings. For instance, dogs belong to the genus "Canis," which is part of the canid family.

Biologist Robert Cowie of the University of Hawaii, not involved in the study, applauds its significance, as it examines extinction rates beyond the species level, shedding light on the loss of entire branches of the Tree of Life concept first developed by Charles Darwin.

The study's findings are grim, indicating that humanity is not merely trimming the edges but wielding a chainsaw to eliminate significant branches of this "tree." According to Anthony Barnosky, professor emeritus at the University of California, Berkeley, the loss of one genus can have far-reaching consequences for entire ecosystems.

The research, which primarily relies on data from the International Union for Conservation of Nature (IUCN), focuses on vertebrate species (excluding fish) due to the availability of data. Of the 5,400 genera studied, comprising 34,600 species, a staggering 73 have become extinct in the last 500 years, with most disappearing in the past two centuries.

Comparing this with the expected extinction rate based on the fossil record over a much longer period, Ceballos points out the severity of the situation. Normally, it should have taken 18,000 years to lose 73 genera, not just 500. However, the accuracy of such estimates remains uncertain due to incomplete fossil records and unknown species.

Human activities, including habitat destruction for agriculture and infrastructure, overfishing, and hunting, are the primary drivers behind this alarming trend. Ceballos underscores the profound impact, likening it to removing bricks from a wall until it collapses, signifying a potential collapse of civilization.

While experts debate whether this marks the onset of a sixth mass extinction, they concur on the alarming current extinction rate. 

To prevent further damage, urgent action is needed to protect and restore natural habitats. 

Ceballos highlights the opportunity to save many genera among the 5,400 at risk if action is taken promptly. However, the window for such action is rapidly narrowing.