Our single-celled ancestor lived in a world without plants, animals or oxygen-rich oceans. Yet, this seemingly simple microorganism took the first steps toward complex life. From this ancestor emerged ...

Eukaryotes—the building blocks of complex life—appeared on Earth 1.7 billion years ago, and now scientists have solved a ...

Archaea—one of the three primary domains of life alongside bacteria and eukaryotes—are often overlooked and sometimes mistaken for bacteria due to their single-celled nature and lack of a nucleus. Yet ...

Ten years ago, nobody knew that Asgard archaea even existed. In 2015, however, researchers examining deep-sea sediments discovered gene fragments that indicated a new and previously undiscovered form ...

Who were our earliest ancestors? The answer could lie in a special group of single-celled organisms with a cytoskeleton similar to that of complex organisms, such as animals and plants. Ten years ago, ...

A new study suggests that ancient microbes once cast as oxygen haters may have actually learned to use the gas, offering a clue to how the first complex cells — and, eventually, all plants and ...

John M. Archibald is in the Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada, and also at the Institute for Comparative Genomics, Dalhousie ...

Current hypotheses suggest that all life on Earth evolved from a common ancestor that diversified into the variety of organisms seen today. Scientists propose that the eukaryotic branch of this family ...

All modern multicellular life — all life that any of us regularly see — is made of cells with a knack for compartmentalization. Recent discoveries are revealing how the first eukaryote got its start.

An artist’s depiction of an Asgard archaeon, based on cryo-electron tomography data: the cell body and appendages feature thread-like skeletal structures, similar to those found in complex cells with ...