Fish

The definition of bioluminescence “is easier than the pronunciation and spelling of the word: It is just visible light made by living animals,” says Edith Widder, president of the Ocean Research and Conservation Association in Fort Pierce, Fla.

The word may be easy to define, but the chemical process is still poorly understood. Bioluminescence has apparently evolved independently at least 40 times in species belonging to bioluminescence remains a poorly understood chemical process that appears to have evolved at least 40 times in species belonging to more than 700 genera. Widder notes in the journal Science that about 80 percent of those genera are found in the open ocean.

Climate change, coastal development and overfishing have effectively wiped out nearly a fifth of the world’s coral reefs, and by the end of this century they “are unlikely to look much like the reefs that we are familiar with today,” said Peter Mumby, a marine biologist at the University of Queensland in Australia, who envisions smaller and weaker reefs that harbor fewer fish.

“But there will still be reefs and they will still be very important,” he said. “And so what we really have to do is take all the steps we can locally to

Check out seven ways scientists and conservationists are pushing to preserve reefs for future generations.

Fossils help scientists peel back the layers of time to reveal stories of life from eras long past. Sometimes the story goes in an unforeseen direction; other fossils have a “wow” factor simply because they were discovered at all. Check out eight surprising fossil finds.

Digital x-ray images of a “bizarre” 300 million-year-old shark relative have revealed the oldest known fossilized brain, researchers announced yesterday.

The unusual discovery raises hopes that scientists will find other ancient brains and use them to study how gray matter has evolved, said John Maisey, a paleontologist at the American Museum of Natural History in New York.

Scientists around the world are celebrating the 200th birthday of British naturalist Charles Darwin, who was born on Feb. 12, 1809. Darwin’s groundbreaking 1859 book, “The Origin of Species,” proposed the theory that species evolve over time through the process of natural selection. Check out seven signs of evolution in action.

Captions for photos of animals in the news. Shots include moon jellyfish, green macaws, sheep bound for Jordan, a rehabilitated eagle, and white rhinoceroses.

Captions for photos of animals in the news. Shots include an “ant from Mars,” a well-dressed camel, resting lions, a captured rhinoceros, and stranded fish in the wake of Hurricane Ike.