Palaeontologists believe a rope-like organism called Funisia dorothea, which lived on the seabed up to 570 million years ago, was the first creature on earth to have sex.
Fossilised remains of the primitive tubular creatures have been uncovered in the Australian outback, from what was once seabed, and have put back the history of sex by about 30 million years. But, whilst the experience was unlikely to have been earth-moving for the animals, the discovery has excited scientists who said that the fossils open a window on one of the most ancient ecosystems, indicating that the planet’s earliest animal ecosystem was complex and included sexual reproduction.
What has gotten the scientists excited is that, until now, Palaeobiologists were generally agreed that the earliest multicellular animals were simple, and that strategies which organisms use today to survive, reproduce and grow in numbers had arisen over time due to many factors, including evolutionary and ecological pressures, imposed by competition for food and other resources.
But in describing the ecology and reproductive strategies of Funisia, the researchers found that the organism had multiple means of growing and propagating - similar to strategies used by most invertebrate organisms for propagation today.
Researchers identified the creature’s capacity for sexual rather than asexual reproduction, because fossil specimens were found in groups that all appeared to be the same age. Since they had all found a foothold in a sandy seabed at the same time, it was considered they must have resulted from a simultaneous spawning instead of uncoordinated asexual births.
Funisia dorothea would have grown in abundance, covering the sea floor, during the Neoproterozoic era, which ended about 540million years ago and lasted for about 100million years of Earth’s history, during which no predators or scavengers were around. Funisia would have lived in dense groups of similar size and age animals, much like Mussels and Oysters do, today.
Mary Droser, one of the Palaeontologists involved in the study and a professor of Earth sciences at the University of California in Riverside, first discovered the organism in 2005 near Ediacara, South Australia, and gave it its name - Funisia after “rope” in Latin - Dorothea after her 80-year-old mother, Dorothy, who took care of the palaeontologist’s young children and cooked for the research team on several digs.
Mrs Droser snr. said she was “thrilled to tears” at having a fossil named in her honour, and thought it appropriate that the ancient animal was the first to have sex:
My family thinks it’s humorous. I have 11 grandchildren - obviously reproduction is a good thing.
Professor Droser and James Gehling of the South Australia Museum reported in the journal Science that Funisia was a soft-bodied creature that grew as 30cm-long tubes. Once the tubular animals had fixed themselves to the seabed, either as a larva or a fertilised egg, they were immobile and unable to go off in search of mates. They were also unable to identify a mouth or any other recognisable anatomy.
Professor Droser said:
In general, individuals of an organism grow close to each other, in part, to ensure reproductive success,
It is common modern ecological strategy, and these guys were doing it in the earliest animal ecosystems on this planet,
In Funisia, we are very likely seeing sexual reproduction in Earth’s early ecosystem – possibly the very first instance of sexual reproduction in animals on our planet. How Funisia appears in the fossils clearly shows that ecosystems were complex very early in the history of animals on Earth.
Posted by Jonathan in Biology, History