Links With Your Coffee
- Yamani or Your Life
A nasty attempt to coerce Danish newspapers into apologizing for the cartoons of Muhammad.
- Assholes have rights
- Eyeless hydra shed light on evolution of the eye
One of creationists' favourite claims is that an organ as intricate as the eye could never have simply evolved. Fresh evidence to the contrary has now arrived, courtesy of a creature related to jellyfish.
The tiny freshwater hydra has no eyes but it will contract into a ball when exposed to sudden bright light. David Plachetzki and colleagues at the University of California, Santa Barbara, have found that hydras "see" light using two proteins closely related to those in our own eyes.
"If you look at something as complex as an eye, you might be at a loss to explain how the whole structure evolved at once," says Plachetzki, now at the University of California, Davis. "But if you look at its components you can start to piece together how it happened." That's especially feasible now that genes from the earliest animals, such as the hydra, are being sequenced.
Rod and cone cells in the human retina contain proteins called opsins that change shape when light strikes them. This causes another type of protein, an ion channel, to generate an electrical signal along nerves connecting the eye to the brain – a process called phototransduction.
Hydras have the same types of opsins and ion channels as we do.
- Amusing sign
- Rachel Corrie's Day in Court
- Story of the Week
LOA goodies. I suggest buying books directly from the LOA but if you dont Library of America books are also available from Amazon
