Earth’s First Animals May Have Thrived Without Benefit Of Oxygen


ODENSE, Denmark (UPI) — The first, most primitive animals may have thrived on Earth in water that contained almost no oxygen, Danish scientists say.

Researchers at the University of Southern Denmark say the finding suggests the rise of animals could have created our modern, oxygen-rich oceans, rather than oxygen-rich oceans triggering the initial rise of animals.

It challenges the standard view that the evolution of animals was delayed by a lack of sufficient oxygen for them to breathe, while it strengthens a theory the first animals may have helped raise oxygen levels, they said.

The scientists collected breadcrumb sponges (Halichondria panicea) from oxygenated waters in a Danish fjord, then kept them in an aquarium from which the oxygen was slowly removed.

Even with just 1/200th of the oxygen currently found in the atmosphere, the sponges survived, and if modern sponges can live with little oxygen, early animals probably could too, the scientists said.

“There are still many researchers who contend that animals could not have arisen until oxygen levels became relatively high,” study leader Danial Mills told “Our results challenge that.”

UPI - United Press International, Inc.

Since 1907, United Press International (UPI) has been a leading provider of critical information to media outlets, businesses, governments and researchers worldwide.

Join the Discussion

Comment Policy: We encourage an open discussion with a wide range of viewpoints, even extreme ones, but we will not tolerate racism, profanity or slanderous comments toward the author(s) or comment participants. Make your case passionately, but civilly. Please don't stoop to name calling. We use filters for spam protection. If your comment does not appear, it is likely because it violates the above policy or contains links or language typical of spam. We reserve the right to remove comments at our discretion.