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Thursday, May 24, 2007

Cannibalistic Fish Keep Their Shape

Some fish of the same species display very different features (“resource polymorphism”) even though they live in the same lake because they eat different foods. A team of European researchers found that early cannibalism is found in all species displaying resource polymorphism.

The effect of early cannibalism is twofold. First, it stabilizes the variation in the number of individuals over time, which in turn increases the benefit of specializing on any resource since the risk of being dependent on a vanishing resource decreases. Second, an early disappearance of small newborn individuals increases the abundance of their prey due to decreased consumption from the small ones, hence increasing the benefit for larger individuals to specialize on this specific prey (typically zooplankton). link
Stabilization of population fluctuations due to cannibalism promotes resource polymorphism in fish. 2007. Jens Andersson, et al. American Naturalist 169:820–829.

Super Fungi Feed on Radiation

Art © Steve Ditko. Space Adventures © current copyright holder.

Scientists have long assumed that fungi exist mainly to decompose matter into chemicals that other organisms can then use. But researchers have found evidence that fungi possess a previously undiscovered talent with profound implications: the ability to use radioactivity as an energy source for making food and spurring their growth.

Those fungi able to "eat" radiation must possess melanin, the pigment found in many if not most fungal species. But up until now, melanin's biological role in fungi—if any--has been a mystery.

"Just as the pigment chlorophyll converts sunlight into chemical energy that allows green plants to live and grow, our research suggests that melanin can use a different portion of the electromagnetic spectrum—ionizing radiation—to benefit the fungi containing it," says Dr. Dadachova.

The research began five years ago when Dr. Casadevall read on the Web that a robot sent into the still-highly-radioactive damaged reactor at Chernobyl had returned with samples of black, melanin-rich fungi that were growing on the reactor's walls.

Fungi exposed to levels of ionizing radiation approximately 500 times higher than background levels grew significantly faster (as measured by the number of colony forming units and dry weight) than when exposed to standard background radiation. link
Ionizing Radiation Changes the Electronic Properties of Melanin and Enhances the Growth of Melanized Fungi. Ekaterina Dadachova, et al. PLoS ONE 2(5): e457.

Pat Boyette: Carrion of the Gods

An on-line article HERE wondered if Pat Boyette and Steve Ditko were the same person. A quick search of the web would show that Boyette produced a lot of great work, most of which was for the ‘smaller’ publishers (e.g. Charlton) and included a lot of nifty gothic horror and Sci-Fi material like this fondly remembered tale:


From Tales of the Macabre #2. Story & Art © Estate of Pat Boyette.

Read a nice interview with Boyette.

A short bio of the man is HERE

Saturday, May 19, 2007

Bigger Is Better (& Smarter)

When it comes to estimating the intelligence of various animal species, it may be as simple measuring overall brain size. In fact, making corrections for a species' body size may be a mistake.
"It's long been known that species with larger body sizes generally have larger brains," said Robert Deaner. "Scientists have generally assumed that this pattern occurs because larger animals require larger nervous systems to coordinate their larger bodies. But our results suggest a simpler reason: larger species are typically smarter."

Deaner said the findings imply that a re-evaluation may be in order for many previous studies that have compared brain size across different animal species, including ancestral hominids.

The new results showed that some primate species consistently outperform others across a broad range of cognitive tasks. It compared how well eight different brain size measures predicted the domain-general cognition variable generated in the earlier study. To the researchers' surprise, overall brain size and overall neocortex size proved to be good predictors, but the various measures that controlled for body size did not. The results did not change even when various statistical assumptions were altered.

Another unexpected finding was that the overall size of the whole brain proved to be just as good a predictor of intelligence as was the overall size of the neocortex. Scientists making cross-species comparisons have often assumed that the neocortex would be more closely linked to intelligence, since it is considered the "thinking part" of the brain. link
Overall Brain Size, and Not Encephalization Quotient, Best Predicts Cognitive Ability across Non-Human Primates. 2007. R. O. Deaner, et al. Brain, Behavior, and Evolution 70: 115-124.

Sunday, May 6, 2007

Crashed This Day: The Hindenburg

In 1937, at 7:25 pm, the dirigible The Hindenburg burned while landing at the naval air station at Lakehurst, N.J. On board were 6l crew and 36 passengers. The landing approach seemed normal, when suddenly a tongue of flame appeared near the stern. Fire spread rapidly through the 7 million cubic feet of hydrogen that filled the balloon. Within a few seconds the Zeppelin exploded in a huge ball of fire. The ship fell tail first with flames shooting out the nose.

It crashed into the ground 32 seconds after the flame was first spotted; 36 people died. Captain Ernst Lehmann survived the crash but died the next day. He muttered "I can't understand it," The cause remains the subject of debate even today. From Today In Science History.

The Crash...

Thursday, May 3, 2007

Why Mothra Doesn’t Exist

Scientists in Sweden asked why insects such as butterflies that have a very high capacity for rapid growth during the larval stage do not continue growing just a few more days. This question is prompted by the common laboratory observation that larger bodied females have the capacity to produce many more eggs than smaller females. Since growing larger seems to be relatively easy for these butterflies, it is difficult to see what keeping them from doing so!

In the paper the researchers report on experiments performed on a Swedish population of the Speckled Wood Butterfly, Pararge aegeria. They show that large females lay more eggs than smaller females if they are allowed to lay eggs throughout each day, but in a situation where only part of the day was suitable for egg-laying the size of the female did not matter for the number of eggs laid.

This exercise suggests that growing to a much larger size typically doesn’t pay off in more eggs laid, and the optimal female size predicted by the model is relatively close to what is actually observed.

The paper concludes that one important reason why insects with a high capacity of larval growth do not evolve towards larger sizes may be that the fecundity [# of offspring produced] benefit is in fact relatively limited under natural conditions.

Mothra To the Rescue!
What Keeps Insects Small? Time Limitation during Oviposition Reduces the Fecundity Benefit of Female Size in a Butterfly. 2007. K. Gotthard, D. Berger, and R. Walters. The American Naturalist, volume 169 (2007), upcoming paper.