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https://www.sciencefocus.com/news/early-...rrible-sex
INTRO: Earth’s first animals weren’t great at reproduction, scientists have revealed. In fact, they were so bad at it that life’s diversity was actually held back for millions of years. It was only when stress and competition led to the arrival of sexual reproduction that the pace of evolution increased.
For the study, researchers from the University of Cambridge studied fossils from the oldest-known animals on Earth, which lived around 574 million years ago. These animals reproduced asexually, creating offspring from only a single parent’s genes.
Reported in the journal Nature Ecology and Evolution, the new study goes some way to explaining a question palaeontologists have long been asking: why animal life remained relatively unchanged on Earth for millions of years.
Some of the earliest creatures were Fractofusus (though they looked more like ferns than animals) which existed during the Ediacaran period between 635 and 539 million years ago.
They didn’t appear to have mouths, organs or limbs, but are believed to have absorbed nutrients from the water around them. They reproduced asexually by sending out clones via runners – just like modern strawberry plants do.
“Life was pretty nice during the Ediacaran, so the need for sex was rather limited,” says lead author Dr Emily Mitchell from Cambridge’s Department of Zoology. “There was relatively little competition, so there was no real pressure to change anything.” (MORE - details)
INTRO: Earth’s first animals weren’t great at reproduction, scientists have revealed. In fact, they were so bad at it that life’s diversity was actually held back for millions of years. It was only when stress and competition led to the arrival of sexual reproduction that the pace of evolution increased.
For the study, researchers from the University of Cambridge studied fossils from the oldest-known animals on Earth, which lived around 574 million years ago. These animals reproduced asexually, creating offspring from only a single parent’s genes.
Reported in the journal Nature Ecology and Evolution, the new study goes some way to explaining a question palaeontologists have long been asking: why animal life remained relatively unchanged on Earth for millions of years.
Some of the earliest creatures were Fractofusus (though they looked more like ferns than animals) which existed during the Ediacaran period between 635 and 539 million years ago.
They didn’t appear to have mouths, organs or limbs, but are believed to have absorbed nutrients from the water around them. They reproduced asexually by sending out clones via runners – just like modern strawberry plants do.
“Life was pretty nice during the Ediacaran, so the need for sex was rather limited,” says lead author Dr Emily Mitchell from Cambridge’s Department of Zoology. “There was relatively little competition, so there was no real pressure to change anything.” (MORE - details)