Animals

Skyrocketing animal diversity a half-billion years ago was linked to spikes and dips in marine oxygen levels, according to a detailed geological study.

By reconstructing prehistoric food webs and analyzing the diverse interactions of humans with other species, the ecologist Jennifer Dunne is developing a new understanding of sustainability through network science.

To make headway on the mystery of consciousness, some researchers are trying a rigorous new way to test competing theories.

Researchers hope that the genes of a glowing squid can illuminate how animals evolved organs for beneficial bacteria.

Jellyfish didn’t need novel genes to take an evolutionary leap in complexity.

A report that a fish can pass the “mirror test” for self-awareness reignites debates about how to define and measure that elusive quality.

How does evolution select the fittest “individuals” when they are ecosystems made up of hosts and their microbiomes? Biologist debate the need to revise theories.

For decades, researchers have commonly assumed that higher oxygen levels led to the sudden diversification of animal life 540 million years ago. But one iconoclast argues the opposite: that new animal behaviors raised oxygen levels and remade the environment.

An unlikely team offers a controversial hypothesis about what enabled animal life to get more complex during the Cambrian explosion.