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.

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...

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!

image

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.

Atlantis Destroyed By Giant Tsunami

A group of scientists have uncovered new evidence that the island of Crete was hit by a massive tsunami at the same time that Minoan culture disappeared.

image

Until about 3,500 years ago, a spectacular ancient civilisation was flourishing in the Eastern Mediterranean. The ancient Minoans were building palaces, paved streets and sewers, while most Europeans were still living in primitive huts.

But around 1500BC the people who spawned the myths of the Minotaur and the Labyrinth abruptly disappeared. Now the mystery of their cataclysmic end may finally have been solved.

"The geo-archaeological deposits contain a number of distinct tsunami signatures," says Dutch-born geologist Professor Hendrik Bruins of the Ben-Gurion University of the Negev in Israel.

"The latter can only have been scooped up from the sea-bed by one mechanism - a powerful tsunami, dumping all these materials together in a destructive swoop," says Professor Bruins. The deposits are up to seven metres above sea level, well above the normal reach of storm waves.

"An event of ferocious force hit the coast of Crete and this wasn't just a Mediterranean storm," says Professor Bruins. Link

Wave of Mutilation:

Born This Day: Immanuel Kant

April 22, 1724 – Feb. 12, 1804

Kant was a German philosopher, trained as a mathematician and physicist, who published his General History of Nature and theory of the Heavens in 1755. This physical view of the universe contained three anticipations of importance to astronomers;

Metaphysics explained by Robert Williams.

1. He made the nebula hypothesis ahead of Laplace.

2. He described the Milky Way as a lens-shaped collection of stars that represented only one of many "island universes," later shown by Herschel.

3. He suggested that friction from tides slowed the rotation of the earth, which was confirmed a century later. In 1770 he became a professor of mathematics, but turned to metaphysics and logic in 1797, the field in which he is best known. link

His theme song:

Medusa's Deep Sea Vent

Art © Barry Smith; Medusa © Marvel Comics

A new "black smoker" -- an undersea mineral chimney emitting hot, iron-darkened water that attracts unusual marine life -- has been discovered at about 8,500 feet underwater by an expedition and dubbed the Medusa hydrothermal vent field.

The researchers picked that name to highlight the presence of a pink form of the jellyfish order Stauromedusae as well as numerous spiky tubeworm casings that festoon the vent chimney and bring to mind "the serpent-haired Medusa of Greek myth," said expedition leader Emily Klein.

"It's astonishing that a rich ecology thrives in these extreme environments," Klein added. She noted, however, that while all the organisms near vents are adapted to the high pressures at these depths, not all experience extremely high temperatures.

"The temperature of the ocean floor is about 2 C and there is a strong temperature gradient as you move away from the vent, so animals living a few inches away may experience temperatures only a few degrees above normal for the ocean floor."

"Despite the great tempeature of the vent water, it doesn't boil until 390 C because pressures on the ocean floor are so great, about 200 times the pressure at sea level," Klein said. The tremendous pressures result from the weight of almost two miles of seawater pressing down from above. link

Colours Out of Time & Space

Scientists studied light absorbed and reflected by organisms on Earth, and determined that if astronomers were to look at the light given off by planets circling distant stars, they might predict that some planets have mostly non-green plants.

Cover by Pete Von Sholly

"We can identify the strongest candidate wavelengths of light for the dominant color of photosynthesis on another planet," said Nancy Kiang, lead author of the study.

On Earth, Kiang and colleagues surveyed light absorbed and reflected by plants and some bacteria during photosynthesis, a process by which plants use energy from sunlight to produce sugar. Organisms that live in different light environments absorb the light colors that are most available. For example, there is a type of bacteria that inhabit murky waters where there is little visible light, and so they use infrared radiation during photosynthesis.

link

According to scientists, the Sun has a specific distribution of colors of light, emitting more of some colors than others. Gases in Earth's air also filter sunlight, absorbing different colors. As a result, more red light particles reach Earth's surface than blue or green light particles, so plants use red light for photosynthesis. There is plenty of light for land plants, so they do not need to use extra green light. But not all stars have the same distribution of light colors as our Sun. Study scientists say they now realize that photosynthesis on extrasolar planets will not necessarily look the same as on Earth.

link

"It makes one appreciate how life on Earth is so intimately adapted to the special qualities of our home planet and Sun," said Kiang. link

Spectral Signatures of Photosynthesis. I. Review of Earth Organisms. 2007. Kiang, et al. Astrobiology 7: 222 -251. N.Y.

Spectral Signatures of Photosynthesis. II. Coevolution with Other Stars And The Atmosphere on Extrasolar Worlds. 2007. N.Y. Kiang, at al. Astrobiology 7: 252 -274

Bill Nelson Asks Max Headroom: Do You Dream In Colour?