September 9, 2011
Australopithecines lived in Africa some 4 million to 2 million years ago. Scientists speculate that the australopithecines gave rise to our own genus, Homo, sometime around 2 million years ago, but there’s not much fossil evidence to show exactly when or how this happened. But last year, scientists led by Lee Berger of the University of Witwatersrand announced they had found a possible candidate ancestor of Homo: Australopithecus sediba. The species lived 1.977 million years ago and resembled Homo in many ways.
This week, the researchers published five papers in the journal Science that provide a more in-depth look at the species. Experts are excited about the fossils, but do not agree on where A. sediba belongs in the human family tree—and in some sense, its discovery muddies the picture of human evolution at this critical transition 2 million years ago.
The new studies analyze two partial skeletons found in Malapa Cave in South Africa: a 12- to 13-year-old male and an adult female. Here’s a rundown of the key findings:
Brain: The researchers studied the size and shape of the young male’s brain by taking X-ray scans of his skull and creating a virtual 3-D endocast. A. sediba had a small brain—420 cubic centimeters—only slightly bigger than a chimpanzee brain or half the size of a Homo erectus brain. But the shape and organization of part of the frontal lobe appear similar to Homo. The team says this may mean brain reorganization came before a big jump in brain size in humans.
Pelvis: The pelvis had a mix of australopithecine- and Homo-like traits. This is interesting because some of A. sediba’s more advanced traits, like the shape and orientation of the ilium, were thought to have evolved in the genus Homo to accommodate bigger-brained babies as they came through the birth canal. But since A. sediba had these features and a small brain, another factor probably drove the evolution of these traits; they could be the result of spending even more time walking on the ground and less time in the trees, the researchers suggest.
Hands and Feet: The team found a nearly complete wrist and hand for the species as well as a partial foot and ankle. The foot had a unique mix of traits not seen in any other hominid, suggesting A. sediba had its own form of upright walking and probably still climbed trees. The hand also indicates A. sediba was a climber, but it shows that the hominid had the musculature and anatomy necessary for a “precision grip,” when the thumb meets the fingertips. This movement is what allows you to thread a needle or hold a pencil—and it probably enabled A. sediba to make and use stone tools, the researchers say, although they have not yet found any tools with the species.
Here’s why A. sediba complicates things. For the species to be the ancestor of Homo, it had to have lived before the first species of that genus. That’s just common sense. And it’s true for what the researchers call the “earliest uncontested evidence” of Homo: Homo erectus, at 1.9 million years ago.
But then there’s the contested evidence. At roughly 2.4 million years ago—before A. sediba— a species called H. habilis (“handy man”) lived in Africa, although the researchers say there is disagreement over what fossils should be included in this species. If this handy man is really the earliest member of Homo, it’s hard to call A. sediba an ancestor (unless, perhaps, additional fossil finds push back A. sediba’s age).
In some ways, H. habilis is more human-like than earlier hominids; it had a much larger brain, for example. But in other ways, such as the anatomy of the hand, A. sediba is more human-like than H. habilis, Berger and his colleagues say. What does this all mean? It’s unclear. But at the very least, several different types of Homo-like hominids probably all lived at about the same time—making it a “most challenging endeavor,” the researchers say, to figure out how these forms relate to each other and which if any best represents the ancestor of our genus.
As paleoanthropologists like to say, more fossils may help clarify things—or muddle them even more.
August 11, 2011
In the new movie Rise of the Planet of the Apes, the leader of the ape revolution can talk. In the real world, apes can’t speak; they have thinner tongues and a higher larynx, or vocal box, than people, making it hard for them to pronounce vowel sounds. But that doesn’t necessarily mean they don’t have the capacity for language—sign language, after all, doesn’t require any vocalization.
Over the years, researchers have succeeded—and failed—in teaching apes to use language. Here’s a look at some of the more famous “talking” apes.
Viki: Viki, a chimpanzee, came closest to being a real talking ape. In the late 1940s and early 1950s, Keith and Catherine Hayes of the Yerkes Laboratories of Primate Biology, then located in Orange Park, Florida, adopted Viki and raised her at home as if she were a human baby. With the Hayeses moving her lips for her, Viki learned to utter “mama.” Eventually, with much difficulty, she managed to say three other words—papa, cup and up—on her own. Viki’s tenure as a talking ape didn’t last long; she died at the age of seven of viral meningitis.
Washoe: In the 1960s, psychologists Allen and Beatrix Gardner of the University of Nevada, Reno recognized that chimpanzees naturally gesture a lot and thought chimps would be well suited for sign language. In 1966, they started working with Washoe. Later, psychologists Roger and Deborah Fouts, now retired from Central Washington University, continued the work. By the end of Washoe’s life in 2007, she knew about 250 signs and could put different signs together to make simple combinations like “Gimmie Sweet” and “You Me Go Out Hurry.” Washoe’s adopted son Loulis also learned to sign—by watching his mother. He was the first ape to learn signs from other apes, not humans. For more on Washoe’s life, read Roger Fouts’ Next of Kin.
Nim: After the success with Washoe, psychologist Herbert Terrace of Columbia University decided to replicate the project. At first, Nim—full name Nim Chimpsky, named after linguist Noam Chomsky who thought language was unique to humans—was raised in a human household. (Washoe had been treated like a person too but had her own trailer.) Later, Nim was removed from the family and his language lessons moved to a lab on Columbia’s campus. In the end, Terrace concluded Nim never really learned language; he had merely been trained to imitate his teachers to get rewards. The sad story of Nim’s life after the project ended is told in the new documentary Project Nim.
Chantek: Chimpanzees are not the only talking apes. In 1978, anthropologist Lyn Miles of the University of Tennessee at Chattanooga began studying an orangutan named Chantek. During eight years of study, Chantek learned 150 signs. He also showed signs of being self-aware: he could recognize himself in a mirror. Today, you can visit Chantek at Zoo Atlanta, his home since 1997.
Koko: Koko the gorilla is probably best known for her love of kittens and Mr. Rogers (and maybe less well-known for her encounter with Captain James T. Kirk). Koko’s sign-language training began in 1972 with then-graduate student Francine (Penny) Patterson of Stanford University. According to the Gorilla Foundation, Koko knows 1,000 signs and understands spoken English. It also claims the gorilla has an IQ somewhere between 70 and 95 (the average human IQ is 100). (Critics, however, remain skeptical about some of Koko’s supposed abilities due to the lack of recent scientific publications supporting the claims. (PDF))
Kanzi: Kanzi, a bonobo, doesn’t use sign language; he uses different combinations of lexigrams, or symbols, to communicate. In the early 1980s, psychologist Sue Savage-Rumbaugh, then of Georgia State University, was trying to teach Kanzi’s mom, Matata, to use the lexigrams; instead, Kanzi was the one who mastered the symbols. Kanzi understands spoken English and knows close to 400 symbols. When he “speaks,” his lexigram usage follows rules of grammar and syntax, according to researchers at the Great Ape Trust in Iowa, where Kanzi now resides. Kanzi is also an accomplished stone-tool maker.
August 5, 2011
It’s the summer of the chimpanzee, at least at the movies. The documentary Project Nim and the sci-fi flick Rise of the Planet of the Apes offer audiences very different forms of simian entertainment, but moviegoers will walk away from both wondering, “Is it ethical to use chimps in research?”
Project Nim chronicles the life of Nim Chimpsky, the chimpanzee who was the focus of one of the most (in)famous ape language studies. In 1973, just days old, Nim was taken from his mom at an ape lab in Oklahoma and brought to New York City. Herbert Terrace, a psychologist at Columbia University, wanted to see if he could communicate with a chimpanzee through language (Nim was named after linguist Noam Chomsky). Because apes do not have the proper physiology to speak, Terrace decided to teach Nim sign language.
The best way to do this, Terrace thought, was to raise Nim among humans. Terrace gave Nim to one of his former graduate students, a mother in a Brady Bunch-style household. Life there was chaotic, with few rules, and no one in Nim’s human family really knew sign language.
Lacking results, Terrace once again took Nim away from his mother. This time he brought him to an old mansion in the New York suburbs owned by Columbia. Nim lived there with a few college students who were his teachers. Nim also made trips to the university’s campus for language training sessions, which he apparently disliked. One former teacher claims Nim used the sign “dirty,” meaning he needed to use the bathroom (he knew how to use a toilet), to get out of the classroom.
As Nim got older, he became stronger, unpredictable—and violent (his teachers have the scars to prove it; he bit one woman’s face so hard that she had a gaping hole in her cheek for months.) This is normal for a chimpanzee. “Nobody keeps a chimp for more than five years,” Terrace says. Soon Terrace ended the project.
Nim is then returned to the Oklahoma lab. This scene is why you should bring tissues to the theater. Nim gets locked up, forced to live alone in a small cage next to the cages of strange creatures he’d never seen before: other chimps. The lab looks like a primate prison. The workers shock the animals with cattle prods to keep them in line. One former worker describes Nim as a “spoiled child.”
Nim’s life gets worse. He is sold to a medical lab for vaccine testing. Later he moves to a sanctuary—for horses. He lives there in almost total isolation, as the owners don’t know how to care for an ape. Nim appears lonely, depressed. It’s heartbreaking.
Nim eventually gets some chimp companionship. But there’s no real happy ending for him. He died in 2000 at the age of 26, quite young for an animal that can live up to 45 years in the wild and 60 in captivity.
The movie begins in Africa with the capture of a female chimpanzee. In the next scene, she’s solving a puzzle in a lab. (Today, chimps used in research are bred in captivity. It is illegal to bring them in from the wild.) This chimp is part of a medical trial for a gene therapy to treat Alzheimer’s. The treatment goes beyond the expectations of medical researcher Will Rodman (played by James Franco); it enhances the cognition of the chimp, making her super-smart. (Ed. note — Mild spoilers ahead, though its nothing you haven’t already seen in the trailers, so consider yourself warned. You can read on after the note below)
The ape passes down her superior intellect to her son, Caesar (played by Andy Serkis with the help of amazing CGI effects). After an unfortunate incident, Caesar’s mom is killed, and the lab manager halts the project and orders all the chimps to be put down. Rodman saves newborn Caesar and takes him home.
This is where Caesar’s life begins to resemble Nim’s. Rodman treats Caesar like a human and teaches him sign language. Several years later, a bigger, stronger Caesar attacks a neighbor while trying to protect Rodman’s father, and is sent away to a primate “sanctuary” that bears a striking resemblance to the Oklahoma lab where Nim lived, right down to the cattle prods. And Caesar must learn how to interact with other apes.
Eventually, Caesar breaks out, steals some of the medicine that made him smart and returns to give it to his ape comrades. The apes revolt and descend on San Francisco. During an incredible battle on the Golden Gate Bridge, it’s clear that the California Highway Patrol—and perhaps all of humankind—is no match for this army of super-simians. By the end (stick around for the credits), it’s clear how the apes will conquer the rest of the world.
What happened to Nim and Caesar made me incredibly sad and made me think about the ethics of captive ape research. I’m not alone.
(Spoiler-concerned readers: You’re safe to read on from here)
Although the premise of Rise of the Planet of the Apes seems absurd, some scientists worry that genetic engineering is advanced enough to create primates with human-like behavior and self-awareness. The U.K. Academy of Medical Sciences released a report last month suggesting such experiments should be off-limits. The United Kingdom along with many other countries already ban the use of great apes in research. The subject is now being debated in the United States.
In the case of Nim, Terrace concluded years after the project ended that the chimp never really understood sign language; he just learned to mimic his teachers to get rewards. As the movie implies, the lack of results could be blamed on the lack of a proper experimental design in the first place. Other apes—most notably Washoe the chimpanzee, Koko the gorilla and Kanzi the bonobo—have been taught to use sign language. The researchers studying them believe they are truly communicating with these animals via language, but there are still some skeptics, including Terrace, who think otherwise.
I have mixed feelings on chimp studies. The sad irony is that the very reason it seems wrong to study chimps is the same reason why they are attractive study subjects: they are our closest living relatives, and the animals that come closest to being like us.
July 20, 2011
For “Predator Week,” I wanted to highlight some unlikely fearsome creatures: venomous mammals. These mammals are a bizarre bunch. The male platypus has spurs on its ankles that release venom, likely to fight off male competitors during mating season. And various species of shrew and the shrew-like solenodon use venomous saliva to disable prey.
The solenodon is particularly fascinating because it delivers its poison just as a snake does—using its teeth as a syringe to inject venom into its target. Not a lot is known about these unusual mammals. There are only two solenodon species: One lives on Cuba and the other on Hispaniola (home to Haiti and the Dominican Republic). At night, they dig in the dirt with their Pinocchio snouts and long claws, looking for grub and waiting to disarm their prey—insects, worms, snails and small frogs and reptiles—with a toxic bite. The BBC has some great video footage of the strange little guys (the solenodon’s venom isn’t lethal to people but notice the handlers still wear gloves).
It readily defends itself against one of its own kind, and probably attacks other animals savagely judging from the way a captive solenodon attacked a young chicken and tore it to pieces with its strong claws, before eating it.
Millions of years ago, venomous mammals may have been more common. But soon the world may lose a couple more: Like many other predators, both species of solenodon are highly endangered. Deforestation and the introduction of dogs, cats and mongooses that eat solenodons threaten to drive the critters to extinction. And in Haiti, people hunt solenodons for food.
Fortunately, the solenodon has recently become the focus of conservation efforts. It would be sad if such a unique, mysterious mammal were gone for good—although I imagine the invertebrates of the Caribbean wouldn’t mind.
Tomorrow in Predator Week: Scientists find the marine version of the Serengeti’s great migrations
July 8, 2011
The four astronauts aboard the space shuttle Atlantis will not be alone when they blast into space today (assuming the launch proceeds as scheduled). The last shuttle mission will also carry 30 mice that are part of an experiment to better understand why astronauts lose bone mass when they hang out in low-Earth orbit.
The mouse study is typical of the type of research that seemed to dominate space shuttle science: investigations devoted to figuring out how the human body—and the microbes that parasitize us—cope with space. It’s the kind of work that’s necessary if we want to safely send people on long-term missions to Mars and beyond.
With all of the talk about the end of the space shuttle program, I wondered what other science has happened aboard Atlantis, Challenger, Columbia, Discovery and Endeavour. I found some surprises. Here are my favorite quirky space shuttle science projects:
A rose in space smells as sweet—or sweeter: The fragrance of flowers comes from the plants’ essential oils. Many environmental factors influence the oils that a flower produces—and one of those factors is apparently gravity. In 1998, the perfume manufacturer International Flavors & Fragrances sent a small rose called Overnight Scentsation into space aboard Discovery. Astronauts grew the rose in a special chamber and collected its oils. In the low-gravity conditions of Earth’s orbit, the flower made fewer essential oils, and the oils it did produce smelled different (a “floral rose aroma” instead of “a very green, fresh rosy note”). Back on Earth, the perfume company synthesized the rose’s space oils to create a new fragrance that is now in Shiseido’s perfume called Zen.
The MGM experiment: MGM doesn’t refer to the movie studio or the Las Vegas casino; it stands for “Mechanics of Granular Materials.” With this experiment, researchers in space studied the effects of earthquakes, sort of. On three shuttle missions, the MGM experiment compressed columns of sand to allow researchers to study the sand’s strength and other mechanical properties. Such properties are relevant to many processes on Earth, such as soil liquefaction. Liquefaction is often a problem during earthquakes: the shaking increases the external forces acting on any water in the ground, causing water pressure to go up. The higher water pressure weakens the soil, making it flow like a liquid and causing buildings to sink. Studying sand in space is beneficial because the lower gravity reduces certain stresses that make it difficult to study liquefaction and similar phenomena on Earth. Sadly, the last MGM experiment flew aboard the Columbia mission that broke up during re-entry in 2003.
The Tunguska mystery solved: Technically, this piece of science didn’t occur aboard the space shuttle, but it certainly benefited from the shuttle program. In 1908, an extraterrestrial object hit Russia, flattening almost 3,500 square miles of Siberian forest near the Podkamennaya Tunguska River. Scientists have debated whether an asteroid or comet caused the impact. Space shuttle exhaust points to a comet. Researchers at Cornell University and Clemson University made the connection after noticing the formation of noctilucent (“night shining”) clouds following two shuttle launches. The brilliant clouds likely formed from the hundreds of tons of water vapor emitted from the shuttle’s engine during takeoff. Historical records note that the night sky similarly lit up after the Tunguska event. The researchers say noctilucent clouds were probably the cause of the glow, suggesting that whatever hit Earth must have released a lot of water into the atmosphere. This makes comets the likely culprit because they, unlike asteroids, carry a lot of ice.
These scientific experiments are fun, but do they justify the hefty price tag of the shuttle program? Probably not. Some might say the program’s greatest scientific achievements relate to the satellites that astronauts brought to space or the repairs they made to the Hubble Space Telescope.
I’ll suggest another achievement, one that’s more personal. As someone who grew up during the shuttle’s early days, the program helped steer me down a scientific path. It certainly helped foster my interest in learning about the world around (and above) me.