Unknown microorganism discovered in California’s Mono Lake could unlock secrets of animal evolution
Scientists have discovered a previously unknown microscopic organism in California’s Mono Lake, which could provide valuable insights into the origins of complex animal life on Earth. The newly identified microorganism is a type of choanoflagellate, a single-celled organism closely related to animals. This discovery is significant as it might help researchers understand the transition from single-celled to multicellular life forms, a crucial step in the evolution of animals.
Link to early animal ancestors
The creatures found in Mono Lake share a common ancestor with the animals that roam the Earth today. This connection is what makes the discovery so important. “I’m fascinated by the origin of animals, but it turns out that you can’t really study it from the fossil record because the first animals were small and squishy,” said Nicole King, a co-author of the study and a professor of molecular and cell biology at UC Berkeley, in an interview with Newsweek.
King further explained that choanoflagellates are “the closest living relatives of animals,” but have been largely overlooked in scientific research. The study, published in the journal mBio, highlights how these organisms, also known as “choanos,” can form multicellular colonies similar to the early stages of animal embryonic development. This characteristic could provide critical clues about ancient evolutionary processes.
Surviving in harsh conditions: Mono Lake’s unique environment
Mono Lake, located in the Eastern Sierra Nevada, is known for its extreme conditions. “Mono Lake is hypersaline; I think it has three times the salinity of the ocean and is hyperalkaline,” King noted. “It also contains high levels of toxins, including cyanide.” These harsh conditions mean that only the most resilient extremophiles, organisms that thrive in extreme environments, can survive in its waters.
Despite its inhospitable environment, the discovery of the choanoflagellate, named Barroeca monosierra, suggests that Mono Lake could offer more undiscovered secrets. The interactions between this organism and bacteria are particularly intriguing. For example, certain bacteria can trigger the choanoflagellate to switch from a single-celled to a multicellular state, mirroring one of the fundamental steps in early animal evolution.
Choanoflagellates’ surprising responses to bacteria
King also pointed out that bacteria can induce these microorganisms to mate, acting almost like an aphrodisiac. This phenomenon causes the typically solitary and asexual choanoflagellates to engage in a form of sexual reproduction when exposed to specific bacterial molecules.
The study’s findings underscore the potential of choanoflagellates to provide new insights into the origins of multicellular life and suggest that even in extreme environments like Mono Lake, there are still many mysteries waiting to be uncovered.