Jellyfish may seem like simple blobs but some have surprisingly sophisticated features, including eyes. These are often just light-sensitive pits but species like the root-arm medusa have complex ‘camera’ eyes, with a lens that focuses light onto a retina. Not only are these organs superficially similar to ours, they’re also constructed from the same genetic building blocks.
Hiroshi Suga from the University of Basel has been studying the eyes of the root-arm medusa (Cladonema radiatum). His work strongly suggests that all animal eyes share a common origin, whether they belong to a human or an insect, an octopus or a jellyfish. The details may be different but they’re all under the control of closely related ‘master genes’ that themselves evolved from a common ancestor.
The Benguela region, off the coast of Namibia, is a shadow of its former self. In the first half of the 20th century, it was one of the world’s most productive ocean areas and supported a thriving fishing community. Today, the plentiful stocks of sardines and anchovies, and the industries that overexploited them, are gone. The water is choked of oxygen and swarming with jellyfish. Plumes of toxic gas frequently erupt from the ocean floor. But one fish, the bearded goby, is positively thriving in this inhospitable ecosystem. It’s a critical link in a food web that’s on the verge of collapse.