Butterflies & Danger in Western Antarctica
• On a sunny day, dozens of white or yellow butterflies can often be seen clustered around a puddle along a dirt road, or even around a damp spot on the ground – they are getting a drink. To a predator, such as a bird, the crowd of butterflies represents a feeding bonanza. However, when a bird disturbs the butterflies, they take off, surrounding it with a whirling crowd of individuals moving in a chaotic pattern. Since it is impossible for the bird to easily pursue one individual, it generally gives up. The butterflies then settle back to the puddle to continue their drinking. (G. Waldbauer, 2012, “How Not to be Eaten,” U. California Press)
• Much remains to be learned about the neuroscience of memory, but scientists are learning more and more about what happens in the brain when we remember a specific event. At present, many scientists believe we remember an event in the following way. At the event, the brain recorded the sights, sounds, smells, and other sensations that were part of the event. For long-term storage, all this information is broken into pieces, and these pieces are shuttled to specific parts of the brain. To recall the event, the brain must reactivate and consolidate all the pieces of the memory. When it has done that, we are able to remember the hot summer day at the riding stable where we had problems mounting our horse before riding off into the countryside and enjoying all the beautiful spring wildflowers. Our brain brings forth the memory in a fraction of a second, and we recall the heat of the day, the odor of the stable, the touch of the horse, and the pleasure we felt when we gazed at all the colorful wildflowers. (“How are Memories Retrieved?”, Science, Oct. 5, 2012 )
• Even though we hear a great deal about loss of sea ice in the Arctic, the more immediate danger may lie in the Antarctic. There is new evidence that Western Antarctica is heating up faster than any region on the planet. This is dangerous because a huge part of the western ice sheet could collapse, which would cause an alarming rise in sea level. Remote weather station data indicate that Western Antarctica has warmed 4.4 degrees F over the last 50 years. This is twice the rise in temperature previously predicted. The ice sheet that may collapse is about the size of Greenland and it holds 10% of the ice of the continent. Will there be a substantial rise in sea level if the planet continues to warm? The answer is yes…the only question is when. (The Week, Jan. 18, 2013; A.J. Monaghan of the National Center for Atmospheric Research)
• A “stem” cell is an unspecialized cell capable of becoming any specialized cell found in the human body. These cells are said to be totipotent, meaning they can develop into specialized cells that make up skin, liver, muscle, etc. Stem cells can be obtained from early embryos. The process of changing from a stem cell to a specialized cell is called differentiation. More information on stem cells will appear in the next Snippets.