Animal Extinctions – 2011 — A year to forget?
The earth has experienced several major extinction events. However, those extinctions, caused by natural events, seemed to have occurred over extremely long time periods. As 2011 draws to a close, Conservation International reports that the number of species that have disappeared because of human interaction is accelerating. They estimate that 10,000 species have gone extinct in just the past 100 years. In addition: “One in three amphibians (32%) and almost half (42%) of turtles and tortoises are now known to be threatened with extinction, along with one in eight birds (12%) and one in four mammals (23%).”
Read more at Global Animal.
No Pain, Species Gain.
A drop of acid on exposed skin will produce a lot of pain in just about any mammal. Not so with the African naked mole-rat. The mole-rats live in deep burrow communities that are densely packed. The air becomes so saturated with carbon dioxide that the acidity levels in the burrows are too high for most mammals to survive. As a consequence, mole-rats evolved unique ion channels, the chemical pathways which are responsible for producing pain signals that the nerves transmit to the brain. The consequence is that mole-rats are completely insensitive to the effects of acid on the skin.
Read more at Red Orbit.
The Bright Lights of the Sea Bottom.
The New York Times reports on Edith Widder, a marine biologist, who is an expert on deep sea bio-luminescence. In a video, Widder describes how the dark, sunless world 3,000 feet below sea level is actually brimming with bio-luminescent organisms, creating a virtual light show that few people ever get to see. However, Widder has also figured out a way to make some of those organisms — bio-luminescent bacteria — a useful early warning system for water pollution. These bacteria can be mixed with water to be tested for pollution. The bacteria respond by producing various densities of light depending on the level of pollution. When compared to the light produced by the same bacteria in healthy water, the result is a compelling visual demonstration of just how polluted the sample water has become.
It may sound like medieval medicine, but hospitals still use live maggots to clean dead tissue from wounds. This is especially useful for diabetic patients whose wounds often do not heal effectively, leaving them susceptible to infection. It turns out that in the short run the maggots are more effective than surgery, because they secrete an enzyme that selectively dissolves dead tissue while leaving healthy tissue alone. The benefit over surgery, however, is short lived and after a week the surgical route ends up producing equally good results. Although safe and effective, the creepiness factor may limit this ancient technique’s widespread use
Read more at Live Science.
Why Grasshoppers Form Mobs.
Desert locusts, the stuff of biblical legend, have two personalities. In their grasshopper behavioral state, they avoid each other and forage for food independently. However, when the dry season arrives and they are forced together in the remaining stands of food, a transformation takes place. The grasshoppers enter a “gregarious stage” in which they begin to flock and ultimately produce swarms of billions – earning the moniker “locusts.” A research team for Cambridge University has been studying this transformation and concludes that a brain protein in the grasshopper, which is implicated in learning behavior, is stimulated by increased contact with other grasshoppers. This produces a kind of feedback loop in which close quarters triggers a “memory” for gregarious behavior that leads to swarming.
Read more at Red Orbit.
Hippos’ Little Cousin, the Pygmy Hippo.
The hippopotamus has only one extant relative – the pygmy hippo. These creatures are only about 1/6 the size of a hippopotamus and live reclusive lives in Africa’s Liberian forests and similar West African “pocket” populations. The pygmy hippo remains something of a mystery to scientists, so recent footage of one in its native habitat captured by a hidden camera offers a rare if fleeting glimpse into the odd creature’s life outside of zoos.
Read more at Scientific American.
More on How Smart Crows Learn.
One of Aesop’s fables imagines a crow that drops pebbles into a narrow container of water so that the water level will rise and he can enjoy a drink. In an experiment conducted by New Zealand psychologists on wild New Caledonian Crows, it turns out that crows can indeed perform this feat, but only if they learn how. In the experiment, a tube containing a floating chunk of meat was just out of the reach of the crow subjects. Pebbles were placed near the tube, but the crows did not deduce that the stones could be used to raise the level of the water. However, when the stones were positioned so that they would accidently drop into the tube as the birds attempted to reach the treat, the crows quickly realized their usefulness. In short order, the crows began dropping stones into the tube, and then began selecting only the largest stones to more quickly raise the floating meat. They also eschewed stone-like Styrofoam chunks as soon as they saw that it floated uselessly on the water.
Read more at Inkfish.
Salmons’ Quick Genetic Response to Hatchery Life.
Salmon raised in hatcheries face a very different environment from those that are born into open waters. Scientists expected evolution to gradually work genetic changes in hatchery salmon, but they have been very surprised by the rate of that change. In as little as a single generation, salmon raised in hatcheries have been selected for and passed on traits particularly suited to their artificial environment. One such trait is believed to be the ability to withstand overcrowding. Of course, this selective pressure works in reverse: hatchery salmon released into the wild have a lower survival rate because they have traits that are less well-suited to natural conditions.
Read more at PhysOrg.
When Putting Things Right Goes Wrong.
In the Pacific Northwest, conservationists have been thinning young Douglas-fir trees in an effort to return the forests to the same conditions as existed in the old-growth forests of years past. The expectation is that this would benefit the northern spotted owl, an endangered species that inhabits these forests. Unfortunately, the effort also adversely impacted the flying squirrel population, which happens to be a mainstay of the owl’s diet. Such backfires from good intentions are not uncommon. As a U.S. Geological Survey representative pointed out, “This is a fairly common problem in restoration ecology, in which there are always winners and losers…”.
Read more at Oregon State University.
Will ‘Chickenosaurus’ Make a 2012 Debut?
In a story reminiscent of Jurassic Park, real life paleontologist Jack Horner describes in entertaining fashion his efforts to reverse-engineer a dinosaur-like creature from chicken DNA. Since birds are the closest living relatives to the dinosaurs, and since genetic advances have accelerated in recent years, Horner believes his goal is within reach.
Read more at TED.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.