Around 560 million years ago, during the Ediacaran period, the first animals emerged. But evolution progressed slowly—because these creatures reproduced without sex. That changed only when environmental conditions like tides and storms put pressure on them. The result: sexual reproduction and an explosive increase in biodiversity.
The researchers from the University of Cambridge describe in their study the prehistoric creature Fractofusus, which reproduced asexually. Without sex, development stagnated for millions of years. Only with the emergence of stress factors—such as changing tides or storms—did sexual reproduction begin. This accelerated evolution and led to the so-called Cambrian explosion, during which the animal world rapidly diversified.
The study provides an answer to a long-unresolved mystery of prehistoric times: why did it take so long for complex life forms to develop? The Cambridge researchers’ thesis: without external pressure, there was no incentive for sex—and thus no genetic mixing that produces new species.
Source: www.zeit.de
