24 MAY / JUNE 2022 popularmechanics.co.zaHOW YOUR WORLD WORKSSCIENCE
/ BY CAROLINE DELBERT /Uh-oh... New research
on extinctions shows life
doesn’t always find a way
F
IVE MASS EXTINCTION EVENTS ARE
generally credited with the state of life on Earth
today, but new scientific evidence suggests
Earth’s history may be marked by additional
extinction events, as well as seemingly incidental
population explosions.
Jennifer Hoyal Cuthill, PhD, a data scientist at
the University of Essex in England, and her colleagues
used a machine-learning algorithm to chart shifts in the
diversity of life over time and found that life doesn’t always
rebound after extinction. This new research ‘goes against
some of the traditional stories about evolution, which focuson mass extinctions and what happens immediately after
them,’ she says.
Scientists often assert that mass extinction events make
way for mass adaptive radiation events, periods when
surviving species evolve and flourish. When the dinosaurs
went extinct roughly 66 million years ago, for instance, the
rest of life on Earth had broader access to food and other
resources. Those species thrived, and eventually gave rise to
humans. The logic follows, but the new research says mass
extinction events are not the sole cause of adaptive
radiation events, if they contribute to those occurrences
at all.The Late
Cretaceous’s
grand finale: an
asteroid, a 1 500 m
tsunami, and
global wildfires.