Animal gastrointestinal tracts harbor a microbiome that is integral to host function, yet species from diverse phyla have evolved a reduced digestive system or lost it completely. Whether such changes ...

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 ...

In a new book, astrophysicist Mario Livio describes how the existence of life on Earth can be traced back to an RNA-based “protocell.” The following is an excerpt from Is Earth Exceptional?: The Quest ...

The origin of life on Earth stands as one of the great mysteries of science. Various answers have been proposed, all of which remain unverified. To find out if we are alone in the galaxy, we will need ...