The most impressive energy transfer system on earth does not involve fossil fuels, or even the thrifty bicycle, but lies within every cell of the billions of leaves that will once again silence winter's gray with the green of spring. Photosynthesis blows away the competition with its astounding energy efficiency of nearly 100% - turning the light of the sun into the chemical stored energy that makes the world go 'round.

Most energy transfer systems, from the chain of a bicycle to the turbines of a power plant, lose much of their potential energy in the form of heat. A new measurement technique, developed by Graham Fleming at the Lawrence Berkley National Laboratory, shows that photosynthesis achieves such an amazing conservation by using a shortcut in the capture of the Sun's energy. Fleming's technique is called Two-dimensional Electronic Spectroscopy and uses femtosecond laser pulses (that's a million billionths of a second!) to probe the inner workings of molecules and the way they transfer energy. In the light harvesting portion of photosynthesis, photons from sun rays excite Chlorophyll molecules which then transfer electrons to light harvesting proteins, ultimately creating a store of energy that powers the formation of sugars. Using their new method, the Berkley group observed that the electron transfer in the Fenna-Matthews-Olson (FMO) light harvesting protein actually skipped predicted steps, seemingly due to the conformation of the protein.

The conformational efficiency of the FMO complex is similar to the way enzymes work. Biological reactions proceeding without enzymes are reminiscent of trying to loosen a rusty Phillips screw with a flat-head screwdriver - possible, but a pain in the rear. Throwing the specified enzyme in the mix is like suddenly having a Phillips screwdriver, some oil to lubricate the whole process and the strength of Andre the Giant. Flemming shows with the new technique that the FMO complex is kind of like an enzyme for energy transfer; it smoothes the whole electron cascade, in this case saving valuable energy in the process.

The real excitement surrounding this discovery lies in the potential to use this new knowledge to inform our own capture of solar energy. According to Flemming, "Nature has designed one of the most exquisitely effective systems for harvesting light, with the steps happening too fast for energy to be wasted as heat. Current solar power systems, however, aren't following Nature's model." It is possible that further investigation into photosynthetic energy transfer will help us develop more effective solar cell technologies. The current photovoltaic cells sparingly popping up throughout deserts and atop Clean Energy homes are only able to transfer the suns energy into electricity with a paltry efficiency of 15%, a joke compared to the solar power of our flora friends. Since photosynthesis at its most basic turns light into moving electrons, understanding this process at such a fine level could bear fruit in a way that no apple tree could have ever imagined - producing a better way to feed our huge apetite for electricity.

In all of evolution, there are few things more mysterious or wonderful than the eye: a little ball of jelly and muscle and cones that somehow turn reflections of light into recognizable images. Its interaction with the brain is one of the most amazing and subtle dances in creation. Unfortunately, it is also one of the most fragile parts, prone to all sorts of nasty accidents, as well as natural decay, which produces both blindness and cliches ("The eyes are the first thing to go"). But a radical breakthrough in neuro-technology may in the next few years help reduce effects of slow blindness, not with traditional medicine but with a tiny microchip planted behind the retina that can communicate directly with the brain

Several different groups are working on this nature-defying innovation, including scientists at Stanford, University of Chicago and Johns Hopkins, all of whom claim to have the better device. But the principal is the same throughout - the microchip, no more than three millimeters, would be planted directly behind the retina. A pair of goggles (think the guy from Star Trek, only probably not as cool-looking) worn by the patient would bring in light and transmit it through a computer onto a LED screen inside the goggles. The image then goes into the eye and through the retinal chip, where photodiodes convert the light images into electrical impulses the brain can perceive as images- which is exactly how a functioning eye works.

This process, coldly described above, is staggering. It is indeed at the forefront of technology, as humans attempt to use the computational aspects of the brain to our benefit. As we learn more and more about how it works, we are getting better at manipulating it. Engineers are using knowledge of the brain's breathtaking design to build better machines, and to build machines that can help the brain. There are several essays on this subject by, among others, Andy Clark and Ray Kurzweil, in John Brockman's excellent "The New Humanists."

The retina chip is just the latest advance, and the most incredible. It is not, so far, helpful for people who are born blind, because in them the brain has no experience in transforming light into electricity. It will help those afflicted with conditions like macular degeneration, the several forms of which slowly blind several million a year (including the author Borges, who said "Gradual blindness is not tragic. It's like the slowly growing darkness of a summer evening"). And the technology is far from perfect - the images won't be clear, but according to Stanford physicist Daniel Palanker, can provide 20/80 vision with which "you can certainly read large forms and live independently...it's a huge step forward."

Oddly, the fine-tuned majesty of the visual system is an argument used by some against evolution. "How," they ask rhetorically, "can something like that just evolve? How could there have there ever been half a functional eye?" This logic becomes shaky when one considers the varied array of light sensitive organs throughout the animal kingdom and Stephen Pinker discusses this argument and the evolution of the eye in his How the Mind Works. What he doesn't discuss is that it will be possible to bring around further evolution of the eye, in a very real sense, by using the technology painstakingly created over the years. This post-evolution will not prevent macular degeneration, but it will negate its effects, which makes it just as effective as anything nature accidentally cooked up.

Homo sapiens comprises an elite squad of the greatest apes in the History of the Earth. Isaac Newton, Zora Neale Hurston, Mother Teresa and John Coltrane were a few impressive squad members. You and I are on the sapiens squad, too. We can prove it by showing off our characteristic genomes, large brains and linguistic prowess. These features have aided our squad in developing rich cultures which have enabled our history of superlatives: we're the only ape squad whose members have played golf on the Moon, who have composed heartbreaking symphonies, and who have written compelling fiction. We're also the only apes who regularly thumb our noses at time and space by traveling at supersonic speeds and communicating across the Internet. And we owe it all to language.

About 6 million years ago, our squad shared ancestry with a similar ape squad, the chimpanzees, whom we call today Pan troglodytes (common chimps). This ape family tree provides some visual perspective on our close relationship to chimps. Note the bonobos, who are equally close relatives, but who have been studied far less frequently than chimps. Also note that 6 million years ago there were no humans, chimps or bonobos. Rather, there was a granddaddy species of ape whose descendants have evolved along different lineages to become the three species around today. You might think of yourself and two of your cousins as showing similar divergence from your common grandparents. Even after 6 million years and many generations of divergent evolution, human and chimp squads share many traits, including those that may seem central to human accomplishment.

Humans and chimps are genetically similar. On average, human genes differ by only 1 percent from analogous chimp genes. The same genes differ by about 0.1 percent between human individuals. So, if you should find yourself watching chimps at a zoo, you might consider that you share at least 99 percent of your genome with the chimps on display and the other zoo patrons. By contrast, mice, with whom we broke evolutionary ranks some 100 million years ago, share only 60 percent of our genome.

Humans and chimps both boast large brains, relative to body size. Among living apes, humans and chimps have the largest and second-largest brains for their bodies. Notably, the brain's frontal cortex, which seems to help us make goals and plan strategies, is the same relative size in chimps and humans. Australopithecines, hominids who may have competed with early members of the genus Homo some 3 million years ago, had a chimp-like brain-body relationship as well.

Humans and chimps are also connected by their use of tools and their tool-related cultures. Wild chimp tool use includes nut cracking on stone anvils and termite "fishing" with long sticks. Studies have shown differences in chimp tool use among troupes, which suggest cultures unique to each troupe.

Even with all these similarities, humans and chimps have developed obviously different cultures. Which of our biological differences might account for the relative complexity of human culture? How important has human language been in our cultural development? Attempts to teach American Sign Language (ASL) to captive chimps, combined with the results of a genetic comparison of humans, chimps and mice, suggest that human use of abstract language has allowed human cultures to develop without the constraints of time and place that may frustrate the growth of chimp cultures.


Big Macs and Oil
The fruit of the oil palm and termites are both common foods for chimps. These foods can be eaten with bare hands, but tools are necessary to get the most out of each source. Palm fruits contain a juicy, fleshy part, which surrounds a hard nut. Both the flesh and the nut are nutritious, but the nut needs cracking for it to become digestible. As social insects, termites make especially good food for chimps because they congregate in stationary mounds. Termite fishing, first seen at Jane Goodall's famous Gombe site, involves poking a stem or twig into a termite mound and pulling out the termites that grab on. Yielding several termites per dip, fishing allows chimps to get more food, faster that they could by hand. Termites of the genus Macrotermes are the largest in Africa and have earned the nickname, "big macs". At least five chimp study sites contain both oil palms and big macs. Chimps at these sites demonstrate variations in tool use that apparently come from troupe cultures, rather than environmental or biological factors.

Chimps at a site called Kasoje, in Tanzania, ignore oil palm fruits altogether. In 20 years of observation, no chimp there has been seen eating either part of the fruit, and no traces of the fruit have been found in fecal samples. At Gombe National Park in Tanzania, chimps feed daily on the fleshy part of palm fruits. They seem to love it. It's their most frequent food source and often stains their faces. Across the continent in Gabon, chimps at a site called Lope also eat the flesh of the fruit. So, neither Kasoje, Gombe, nor Lope chimps bother with the hard nut. But two other troupes do. In Guinea, chimps at Bossou crack open palm nuts with hammers and anvils made of stone. Their tools and techniques for nut cracking are so like those of nearby human villagers, who also eat the fruits, that their worksites are almost indistinguishable. Chimps at Tai in Ivory Coast, are among the best stone tool users, cracking nuts from five plant species. But, for unknown reasons, they avoid the oil palm fruits! Given that oil palms grow in the habitats of all 5 troupes, differing cultural knowledge or norms seem like the best explanation for their different uses of the fruits.

Termites present a similar case for cultural diversity. Chimps ignore big mac termites at the the Lope, Tai, and Bossou sites, though Tai chimps do eat several other termite species. At Kasoje, chimps sometimes fish for big macs, and at Gombe, they're a staple food. Kasoje and Gombe chimps also regularly eat termites from the genus Pseudacanthotermes. Some Kasoje chimps fish for them, while others topple entire termite mounds and eat the frantic workers and soldiers by hand. Gombe chimps never fish for Pseudacanthotermes, preferring to eat them by hand as they come out of their mounds. Here, the Gombe chimps present the clearest example of cultural behavior: they use tools to efficiently get at big macs, but for more unknown reasons, not at Pseudacanthotermes.

If differing tools and food sources don't convince you that chimp troupes have unique cultures, try mentally swapping humans for chimps. If you observed 5 troupes of humans using palm fruits and termites in 5 different ways, you would probably have no qualms about identifying 5 distinct cultures. You could also imagine a sort of Iron Chef Tanzania in which chimp Iron Chefs Gombe and Kasoje prepare the same secret ingredient differently--in this case, big mac termites. Of course culture is at play, just as it is during a human Iron Chef cook-off.


Dr. Zaius, would an ape make a human doll--that TALKS?
Language seems a significant factor in setting apart human and chimp culture. A quirky chimp called Lucy demonstrated the potential for chimps raised in captivity to mimic human tool use and culture. In Chimpanzee Material Culture, Bill McGrew writes, "Lucy was taught many signs in American Sign Language, but more startling was her spontaneous tool use: she was inclined to fix herself a martini, leaf through National Geographic, and then masturbate with a vacuum cleaner!" Other captive chimps have shown impressive language-like behavior. Nim Chimpsky, a chimp at Columbia University, also learned some ASL. His most baroque signing phrase was "Give orange me give eat orange me eat orange give me eat orange give me you." This phrase is meaningful and emphatic, but it only shows Nim's response to his immediate circumstances. It doesn't show thoughtful use of language, which could facilitate cultural development.

Despite cultural variation among wild chimp troupes and idiosyncratic, human-like behavior of captive chimps, no chimps have been observed teaching or actively spreading culture. At Kasoje, two chimps migrated from a termite-fishing troupe to a non-fishing group, but the second troupe was never seen to acquire fishing know-how. That the migrating chimps might try to share fishing knowledge with their new troupe seems straightforward enough. So, why didn't they?

A 2003 study of genes shared by humans, chimps, and mice suggests one answer. Comparison indicated that 98 genes related to sensory perception and 21 genes related specifically to hearing underwent accelerated selection along the human lineage. The most significantly accelerated human gene encodes a protein which is crucial to sound transduction in the inner ear. It is tempting to conclude, but not certain, that these genes permit the human ear for language. Without the human variants of these genes and other genes related to linguistic cognition, chimps seem to have failed to develop any language that deals with subjects other than the here-and-now. Thus it may be impossible for chimps, or it may never occur to them, to communicate unfamiliar ideas such as how to fish for termites.


A little Biology, Language and a lot of culture
What is it about language that has allowed the sapiens squad to develop complex culture and advanced know-how? Consider a troupe of naive, cultureless, naked humans and a troupe of naive, cultureless, naked chimps living side-by-side in a Gombe-like cartoon forest. These troupes are not like any living human hunter-gatherer societies, nor any living chimp troupe because all humans and chimps today have at least 6 million years of living, breathing culture under their belts.

With no culture and no survival know-how, the two cartoon troupes would have to learn from scratch things like whether and how to eat oil palm fruits. At first, with their similar brains and bodies, both troupes should survive equally well. At some point, maybe by accident, one member of each troupe might crack open a palm nut and find its insides delicious. After that point, language becomes crucial. The lucky chimp might continue about her day and never really communicate to her troupemates the secret of the palm nut. It would be left to chance whether any other chimps might see her in the act of cracking, and further chance whether any other chimps would adopt the behavior. Eager young chimps might be the best candidates for learning and embracing the way of the palm nut. In that case, development of a fully entrenched palm nut culture in the chimp troupe could take generations.

But the lucky human, call her Gloria, could use language to share her discovery. She might run across a troupemate and say, "Steve, your face is all orange." He might reply,
"You bet. Palm fruits. I just ate a whole bunch."
"Good stuff, man. So, you know that thing in the middle?"
"Do I ever. Gloria, I hate that thing."
"Well, the other day..."
And away they'd go. Gloria's last remark would be the crucial one, not just because she would proceed to tell Steve about cracking and eating a palm nut, but because it illustrates the power of language (or at least small talk) to remind us of the past. Surely the lucky chimp would retain a memory of her palm nut experience, but without language she might never recall the memory at a time when she could share it with others. Gloria had the double advantage of having her memory jogged by a receptive listener and of being able to recreate her experience verbally, on the spot. In this case, the secret of the palm nut could be spread quickly - within a single generation. And it could spread over space, too. What if Gloria were a newly migrated recruit of Steve's troupe? Although Gloria's example is a cartoon and may be far-fetched, it's harder to imagine a scenario with chimps that accomplishes the same end.

The measurably small genetic differences between humans and chimps may represent a small push over a big cliff. Language and language-related genes have allowed us to reflect and innovate quickly and collectively, and to pass our progress from generation to generation. Written language, beyond the scope of this discussion, sets the stage for marvelous intergenerational communication - the shoulders of giants, if you will. Gigantic sapiens squad member Charles Darwin was unaware of Gregor Mendel's work on the genetic inheritance of traits in pea plants, in part because they spoke different languages. Without Mendel's potentially valuable input, Darwin imagined that an individual's acquired characteristics could be passed on to future generations. But natural selection is slower than that, and only operates on genetic traits acquired at conception. Language has circumvented the genetic speed limit and quickened the pace of human cultural development so extremely that chimps, our closest contemporary relatives, seem to be standing still. Thus, Ham and Enos, the two outstanding chimps who have been to space, were launched there by the sapiens squad.


SOURCES AND GOOD READING
The mouse offshoot of the human genome project
Primate frontal lobes in the news
A lecture on primate brain-body relationships
This book reviews chimp studies to date:
Chimpanzee Material Culture, by W.C. McGrew. Cambridge University Press, 1992.
ALSO, Scientific American Frontiers streams episodes online. These two, on related topics, are good watching: "Chimp Minds" deals with "termite" fishing and learning by young chimps. The episode is divided into segments. "Life's Really Big Questions" deals with genetics, human origins and language.

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