Evolution

Paradoxically, natural selection can sometimes seem to block organisms from evolving useful adaptations. But a new study of “fitness landscapes” and antibiotic resistance in bacteria shows that life still finds a way.

Cells in the placenta have an unusual trick for activating gentle immune defenses and keeping them turned on when no infection is present. It involves crafting and deploying a fake virus.

A new analysis of ancient sediments fills a gap in the fossil record — revealing a massive dynasty of ancient eukaryotes, which may have reigned for 800 million years and shaped the history of life of Earth.

Why did mammals, grasses and some other groups of organisms explode in diversity only after millions of years? The evolutionary biologist Andreas Wagner plumbs the secrets of those “sleeping beauties.”

By watching “minimal” cells regain the fitness they lost, researchers are testing whether a genome can be too simple to evolve.

The reshuffling of neurons during fruit fly metamorphosis suggests that larval memories don’t persist in adults.

In some deep subterranean aquifers, cells have a chemical trick for making oxygen that could sustain whole underground ecosystems.

Changes in the 3D structure of their genome gave skates and rays their distinctive winglike fins and pancake flatness.

A new genetics study of ant “social parasites” shows how complex sets of features can emerge rapidly and potentially split species.