March 13, Good Science News. #9. The Big Blue.
Two weeks ago, I read synopses of three scientific articles published in February. In last week’s edition of Good Science News, I discussed one of them, the article that dealt with the cuttlefish, a squid-like creature that exhibits delayed gratification. This animal would prefer to have a tastier meal later than have a less desirable meal now. In effect these animals were passing the marshmallow test, a test often used to ascertain cognitive development in children. The second article was published in the journal, Frontiers in Marine Science, and focused on three species of deep-sea sharks and their capacity for bioluminescence. That's right, these sharks can manufacture their own light! The kitefin shark, the largest of the three, is the largest vertebrate known to date that has this ability. All three sharks produce counter illumination, meaning that their ventral surface, also known as their bellies, are illuminated while their backs remain dark. The smaller sharks may be using counter-illumination as a form of camouflage, for even though these animals live in the deep ocean, an animal beneath them would see a silhouette of their shape as the shark swam above them. By illuminating their undersides, these smaller sharks may be blending in with the waters above them, and by doing so, may be hiding from predators. But what about the kitefin shark, who, at their size, have no predators lurking below them? There are two prevalent ideas for why they are counter illuminated. One is that they use the illumination to help see their prey items below them on the sea floor. A flashlight of sorts. The second is that these sharks are also using the light as camouflage, so not to give their location away to potential food items. Article three was published in the Proceedings of the Royal Society regarding whales and their uncanny ability to avoid cancer. Large baleen whales, the species that eat krill, can live for up to 200 years and have one of the longest lifespans of any mammal. Given their size (meaning how many total cells there are in their bodies) and given their lifespan, one would imagine that sooner or later a cell would go rogue, start to divide uncontrollably and initiate the formation of a tumor. But it doesn’t happen, anywhere near as often as one would predict. Part of the reason is that natural selection has provided baleen whales with a rapid rate of evolution of tumor suppressing genes, over twice as fast as that of any other mammal. Cuttlefish passing cognitive tests, sharks creating their own light, whales synthesizing genes that help them avoid cancer. And here is the good news. The ocean, like the Amazonian rain forest, holds a rich diversity of animal and plant life. These plants an animals are currently displaying molecular, morphological and behavioral traits that are, at this writing unknown to science. Some of those traits, such as cancer prevention in baleen whales, may actually be beneficial to humans in one way or another. Others, such as bioluminescent sharks, may simply be very cool. Regardless, there is a whole world of life down there, doing things that tax our imagination. Now I have nothing against space exploration as is evident by the fact that Mars was a topic of Good Science News #6. But the mystery behind whether or not there has ever been life on Mars, holds no more sway, scientifically, than do molecular, morphological and behavioral mysteries that are contained within the oceans of the world. So that is the good science news for today. If you are scientifically inclined, or even just curious about the natural world about you, don’t leave earth just yet! There are boatloads of great scientific mysteries that have yet to be unraveled right here at home!