Roundup of Recent Science Discoveries, 2000
Ice Age Haute Couture
According to recent research by archaeologists at the University of Illinois at Urbana-Champaign, the well-dressed Ice Age woman's outfit doesn't resemble anything like the crude hide and fur garments that Wilma Flintstone wore. Instead, the warm weather clothing of at least some of our ancestors included caps or snoods, belts, skirts, bandeaux (banding over the breasts), bracelets, and necklaces—all constructed of plant fibers in a great variety of woven textiles.
The finest weaves of Ice Age seamstresses are comparable not only to Neolithic but even later Bronze and Iron Age products and, in fact, to some of the thin cotton and linen worn today. The new evidence comes in part from a study of 80 textile impressions found on tiny clay fragments in the Czech Republic. The impressions are the earliest evidence for cordage and textile production in the world and reflect technologies heretofore only associated with fine garments of later periods.
Antisocial Brain Tissue Deficit
University of Southern California researchers studied 21 men who were all diagnosed with Antisocial Personality Disorder (APD), which is characterized by irresponsibility, deceitfulness, impulsiveness, irritability, lack of emotional depth and conscience, and lifelong antisocial behavior. All of the subjects had committed serious violent crimes. Using brain-imaging techniques, researchers found that the antisocial men had an 11%–14% reduction in the volume of nerve cells in the prefrontal cortex compared to normal males.
The prefrontal cortex is the brain's foremost outer portion, located right behind the eyes. This region seems to house the mental machinery that enables most people to learn moral sensibilities and to exercise self-restraint. Previous research has shown that convicted murderers and other violent offenders have poor functioning in that region. The new findings demonstrate that a physical abnormality may underlie the poor functioning in these violent antisocial men and that society may have to rethink how it regards violent crime, punishment, and the scope of free will.
New Orleans, the New Atlantis?
According to projections by the U.S. Geological Survey, the city of New Orleans may be submerged under water by the year 2100 due to subsidence (the natural sinking of land), wetland loss, predicted sea-level rise, and an absence of proper restoration programs.
Researchers at the University of New Orleans have spent years identifying the problems causing the catastrophic coastal conditions. Currently, 40% of all coastal wetlands in the United States are located in Louisiana, and 80% of all wetland loss in the nation occurs in Louisiana. From 1930 to 1990, the Mississippi River Delta lost more than 1,000 square miles of land. The current land loss rate is approximately 25 square miles (16,000 acres) of wetlands per year, and the city of New Orleans is sinking three feet per century.
Despite the city's bleak future, researchers have shown that the coastal ecosystem, while damaged, is sufficiently intact for restoration efforts to manage the problem.
Snow Falling on Water
A team of researchers have discovered that when a snowflake falls onto a body of water, it deposits a tiny amount of air just beneath the surface. Before the bubble reaches the surface and pops, it sends out a piercing sound. This sound, ranging from 50 to 200 kilohertz, is too high-pitched to be heard by human ears, which generally pick up nothing higher than 20 kilohertz. However, to porpoises and other aquatic animals that can hear the higher frequencies, the falling snowflakes create an enormous racket just below the surface. Falling snow can add 30 decibels to underwater noise levels. Beyond its deafening impact on water animals, snowflake noise can create “electronic clutter” for people who use sensitive sonar devices.
First Cloned Piglets
The U.S. staff of PPL Therapeutics, Scotland, cloned five healthy female piglets, born on March 5, 2000, in Blacksburg, Virginia. This is the first time cloned pigs have been produced from adult pig cells. Their birth marks the first step in making genetically modified pigs whose organs and cells can be successfully transplanted into humans without being rejected by the human immune system. The process of xenotransplantation (the transfer of organs from one species to another) may one day solve the worldwide organ shortage problem.
Our Tiniest Ancestor
In March 2000, a team of researchers led by Northern Illinois University paleontologist Dan Gebo announced their discovery of the fossil bones of 45-million-year-old monkeylike primates, the smallest primates ever found. The new species, named Eosimias (“dawn monkey”), was discovered in a limestone quarry in eastern China.
Its foot bones are the size of grains of rice, and it weighs less than a dozen paper clips. Yet the miniature “Dawn Monkey” could represent an evolutionary link between lower primates and higher primates, a group that includes apes and humans. The structure of its tiny ankle bones suggests that it could walk flat-footed, using all four legs, like advanced primates. Unlike advanced primates, however, it probably “didn't have a lot of time to be social,” guesses one scientist. That's because the little animal had to spend most of its time eating to feed its high-speed metabolism—when it wasn't trying to avoid being eaten by bigger creatures. The discovery of this specimen in Asia suggests that our earliest ancestors did not live in Africa alone, as previously thought.
The researchers said that the minute mammals were tree dwellers that relied on a steady diet of insects, fruit, and nectar to fuel their high metabolisms. Unlike contemporary higher primates, the tiny primates likely were nocturnal and solitary creatures.
Snakes with Legs?
The fossil of a new species of snake with small front and hind limbs was found in 95-million-year-old deposits near Jerusalem. The site was once an ancient marine environment, suggesting a seafaring lifestyle for the fossilized snake. Dubbed Haasiophis terrasanctus, it is the second limbed species of primitive snake to come from there.
The first such species, Pachyrhachis problematicus, is thought by some paleontologists to be a transitional link between mosasaurs—gigantic swimming lizards of the Cretaceous period—and true snakes. This view of snakes originating in the sea contrasts with the traditional view that snake ancestors were small terrestrial or burrowing lizards who eventually lost their legs through evolution.
A group of scientists from the Field Museum in Chicago and the Hebrew University of Jerusalem have concluded that the new species was closely related to Pachyrhachis. Each of the fossil animals has a hinged upper jaw and a skull that completely surrounds the brain, features not found in lizards.
It is not known how the legs themselves might have been used since they are too small in relation to the animal's body to have any locomotor function.
Our Ancestors Were Knuckle-Walkers
A new study by Brian Richmond and David Strait of George Washington University that scrutinized the fossilized wrist joints of two of our earliest known human ancestors, A. afarensis (best known as “Lucy”) and A. anamensis, concluded that our earliest known human ancestors probably walked on their knuckles in a way similar to modern chimpanzees and gorillas. This discovery lends support to the theory that humans didn't evolve from tree dwellers, but from ancestors who were already adapted to walking on the ground.
The researchers compared the fossilized wrist joints from known human ancestors with the wrist joints of other primates. The wrist anatomy of Lucy and her cousins resembles that of chimpanzees and gorillas in having features that buttress the wrist joint and help to lock the wrist into a stable position so that the animal can support its weight on its fingers. It was not until the later species, A. africanus, at 2 to 3 million years ago, that evidence of a more humanlike, flexible wrist joint exists.
Solar “Heartbeat” Discovered
Astronomers from the National Science Foundation's National Solar Observatory have discovered a “solar heartbeat” in the motion of the layers of gas circulating beneath the Sun's surface. Their research shows that some parallel layers speed up and slow down rhythmically about every 16 months. This internal cyclic action may explain the formation of sunspots and solar flares.
The Sun is not a solid object—it is made up of layers of gas. Unlike Earth, all points on the solar surface do not rotate at the same rate. Its equatorial region rotates once every 27 days, while the regions at the Sun's poles rotate at a slower rate of once every 35 days. The “differential” rotation extends through the Sun's turbulent convective layer, located about 130,494 miles (210,000 kilometers) below the surface, nearly one-third of the distance to the solar core. At the edge of the convective layer, the rotation period varies, completing a cycle about every 15–16 days. Astronomers think that the patterns of these internal movements are connected to the cycles of eruptions seen on the surface.
New Killer Crater
Geoscientists at the Geological Survey of Western Australia and the Australian National University discovered the world's fourth-largest asteroid impact crater in western Australia. Buried beneath the red-sand country east of Shark Bay, the huge crater centered on Woodleigh Station is estimated to be 75 miles (120 kilometers) in diameter. It is the result of a massive 3.1-mile- (5-kilometer-) wide asteroid that smashed into Earth some 200–360 million years ago. The impact would probably have resulted in an extinction event similar to the Chicxulub impact in the Gulf of Mexico, which has been linked to the extinction of the dinosaurs at the end of the Cretaceous period, 65 million years ago.
The Woodleigh crater's estimated age probably coincides with one of three extinction events known in the fossil record: the Late Devonian extinction (364 million years), the end of the Permian period (247 million years), or the end of the Triassic period (214 million years).
Awesome Ape-Man Find
In April 2000, scientists at the University of Witwatersrand, South Africa, announced the discovery of two early hominid fossils excavated in the Sterkfontein caves, 4 miles (7 kilometers) northwest of Johannesburg. The fossils comprise the most complete female skull ever found of her species, together with the lower jawbone of a male. The 1.5- to 2-million-year-old pair were christened Orpheus and Eurydice (after the ancient Greek mythological lovers). They were identified as Paranthropus (“beside man”) robustus, a type of Australopithecine (“ape man”) known for its huge teeth. They were not direct descendants of modern humans but were a line of hominids that became extinct about one million years ago.
For the first time, scientists now know what a male and female Paranthropus looked like and what the differences were between male and female skulls. The top of the male's skull features a ridge, called a sagittal crest, to which the muscles of the lower jaw were anchored. The female, apart from being smaller than the male, has no such crest—a distinction echoed among male and female gorillas today.
Orpheus and Eurydice were largely vegetarians but may have included some meat in their diet from scavenged kills. They may even have used tools.
It's a Smaller World After All
New calculations made by University of Washington scientists for Earth's mass were reported in May 2000. According to UW physicists Jens Gundlach and Stephen Merkowitaz, Earth weighs in at 5.972 sextillion (5,972 followed by 18 zeros) metric tons. Recent textbooks list the weight as 5.98 sextillion metric tons. Either way, that's about one trillion metric tons for each person on Earth.
To make their precise measurements, the researchers used a computer-controlled device called a torsion balance that records nearly imperceptible accelerations from the gravitational effects of four 8.14-kilogram (18-pound) stainless-steel balls on a 7.62-by-3.81-centimeter (3-by-1.5-inch) gold-coated Pyrex plate just 1.5 millimeters (0.591 inches) thick.
Astronomers using the world's most powerful radio telescope at Arecibo, Puerto Rico, have captured radar images of a giant, dog-bone–shaped asteroid located in the main asteroid belt between Mars and Jupiter. They are the first images ever made of a main-belt asteroid. The unusual space rock, named 216 Kleopatra, measures about 135 miles (217 kilometers) long and about 58 miles (94 kilometers) wide, roughly the size of the state of New Jersey.
Although the massive asteroid was discovered in 1880, its peculiar dog-bone or distorted dumbbell-like shape was unknown until now. Its strange appearance could have been produced by an incredibly violent collision between two asteroids that did not completely shatter and disperse all the fragments. Or it may once have comprised two separate lobes in orbit around each other with empty space between them, and subsequent impacts filled in the space with debris.
Radar observations of Kleopatra seem to indicate that its surface is porous and loosely consolidated. Its interior appears to be composed of mostly solid metal fragments, possibly an nickel-iron alloy.
First Out-of-Africa Ancestors
A team of Georgian, German, French, and U.S. researchers reported finding a nearly complete fossil cranium and another skullcap representing the earliest known human ancestors from Eurasia, at a site in Dmanisi, Georgia. The 1.7-million-year-old fossils are the first discovered outside of Africa that show clear signs of African ancestry.
Their age and skeletal characteristics link them to the early African species Homo ergaster, a species that some scientists believe is the African version of Homo erectus. The new evidence suggests that they may have been the first hominid species to journey out of Africa.
Stone tools of the less sophisticated “pebble-chopper type,” predating the Acheulean or hand-ax tradition, were found in the sediment with the skulls, contradicting the theory that early humans didn't leave Africa until after they had invented technically advanced tools. Despite the ready availability of raw material, all of the Dmanisi artifacts found at the site are of a pre-Acheulean type that appeared in Africa as early as 2.4 million years ago. Stone Age tools featuring hand-axes, cleavers, scrapers, and sharp stone flakes are called Acheulean (from St. Acheul in France).
Rare Arctic Asteroid
On January 18, 2000, an estimated 23-foot- (7-meter-) wide, 250-metric-ton fireball as bright as the Sun streaked across the skies of western Canada and exploded with an estimated yield of 5–10 thousand tons of TNT. Scientists were able to pick up the remnants of the brilliant meteor—the first time freshly fallen meteor pieces were quickly recovered and brought to a lab untouched, on ice, and never thawed.
The Yukon meteor fragments were identified as carbonaceous chondrites, the most pristine, organically rich meteorites known. Carbonaceous chondrites are rare and difficult to recover because they are so fragile, easily breaking down during entry into Earth's atmosphere and during weathering on the ground. They comprise only about 2 percent of all meteorites known to have fallen to Earth.
What is probably the largest living organism on Earth has been discovered by scientists in the Malheur National Forest in the Blue Ridge Mountains of eastern Oregon. A fungus living three feet underground is estimated to cover 2,200 acres. Officially known as the Armillaria ostoyae, or the honey mushroom, the fungus is 3.5 miles across and takes up an astonishing 1,665 football fields. The small mushrooms visible growing above ground are only the tip of the iceberg. Experts estimate that the giant mushroom is at least 2,400 years old, but possibly as old as 7,200 years. By testing samples from various locations, scientists determined that the enormous growth is all one organism. Previously, the world’s largest organism was believed to be another Armillaria ostoyae living near Mt. Adams in Washington State.