Around 1.7 billion years ago, eukaryotes—the building blocks of complex life—first appeared on Earth, and now scientists have ...

Scientists are trying to understand how complex life emerged on Earth about 2 billion years ago. Our microbial ancestors could be the key.

For billions of years after the origin of life, the only living things on Earth were tiny, primitive cells resembling today’s bacteria. But then, more than 1.5 billion years ago, something remarkable ...

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 ...

Editor’s Note: Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Plants, algae, fungi, and animals — ...

The sun has just set on a quiet mudflat in Australia’s Northern Territory; it’ll set again in another 19 hours. A young moon looms large over the desolate landscape. No animals scurry in the waning ...

For billions of years after the origin of life, the only living things on Earth were tiny, primitive cells resembling today’s bacteria. But then, more than 1.5 billion years ago, something remarkable ...

The origin of the nucleus remains hotly debated among scientists, but new imaging and genomic data are shedding light on this billion-year-old mystery.

The origin of complex cells started without oxygen, new research suggests. Since the 1960s, many experts have argued that the emergence of eukaryotes (cells containing a clearly defined nucleus) ...

A lot happened in the hundreds of millions years separating the first and last eukaryotic common ancestors, but when and how most features arose remains a mystery. Eukaryogenesis is broadly defined as ...