The tree of life is a metaphor used to describe the evolutionary relationships between all living organisms. It is represented as a branching diagram, with different branches representing different groups of organisms that share a common ancestor.
A new branch has been discovered on the tree of life, and it is composed of predators that nibble their prey to death.
These microbial predators are divided into two groups, one of which has been referred to as “nibblerids” due to their use of tooth-like structures to bite off pieces of their prey. The other group, known as “nebulids,” consume their prey whole. Both groups form a distinct ancient branch called “Provora,” according to a recent study published in the journal Nature.
Microbial lions
Like lions, cheetahs, and more familiar predators, these microbes are numerically rare but important to the ecosystem, says senior author Dr. Patrick Keeling, professor at the University of British Columbia department of botany. “Imagine if you were an alien and sampled the Serengeti: you would get a lot of plants and maybe a gazelle, but no lions. But lions do matter, even if they are rare. These are lions of the microbial world.”
Using water samples from marine habitats around the world, including the coral reefs of Curaçao, sediment from the Black and Red seas, and water from the northeast Pacific and Arctic oceans, the researchers discovered new microbes. “I noticed that in some water samples, there were tiny organisms with two flagella, or tails, that convulsively spun in place or swam very quickly. Thus began my hunt for these microbes,” said first author Dr. Denis Tikhonenkov, senior researcher at the Institute for Biology of Inland Waters of the Russian Academy of Sciences.
Dr. Tikhonenkov, a long-time collaborator of the UBC co-authors, noticed that in samples where these microbes were present, almost all others disappeared after one to two days. They were being eaten. Dr. Tikhonenkov fed the voracious predators with pre-grown peaceful protozoa, cultivating the organisms in order to study their DOI: 10.1038/s41586-022-05511-5
