Suzanne Vega composed and sang a haunting song about a battered child in 1987 called "My Name is Luca." In some ways, Luca, the acronym for the Last Universal Common Ancestor, way before Lucy, is the scientific equivalent of a battered child. The scientist who finds Luca, who it is estimated to have appeared between 3.6 and 4.1 billion years ago, will win that million dollar prize mentioned earlier. All life derived from Luca. However, Luca was not probably the very first life form. Nature experimented, and Luca survived. Earlier than Luca was Lua, for last universal ancestor. To some, they are the same, but fortunately, Luca prevailed at that historic gathering of 1996 in Provence, because lua in Hawaiian is outhouse.
There are three branches of life: bacteria, archaea and eucaryotes. The first two are simpler, called prokaryotes, having no nucleus and with all genetic material in a single filament of DNA. E. coli is a typical bacterium, and, well, you wouldn’t recognize one archaea from another. Algae are eukaryotic, and so are amoeba and paramecium, microbes you all saw in your high school microscope. Eucaryotes have a nucleus containing genetic material. As they are more complicated, it was earlier thought that bacteria and archaea were first to come, especially archaea—which was only identified in 1977 by American microbiologist Carl Woese and American chemical engineer George Fox—and mostly consists of extremophiles, those organisms that live in extreme environments. There is one line of reasoning, called fusion, where archaea and bacteria combined to form eucaryotes. This is beginning to lose favor.
Others have advanced an argument that eucaryotes were the first of the three, and, therefore, Luca was one of them. It turns out that the prokaryotes are more efficient than eucaryotes, representing a kind of natural selection, so instead of fusion, the three domains of life resulted from fission. Then, too, what about viruses? But life is not all that simple, for there are at least five tribes of beliefs representing one organism or the other, or something in between, or, perhaps, none of them at all. I’m leaning towards viruses as the precursors to life, as DNA first came from them, which are, nevertheless considered by most biologists to be non-living. A readable (and free) publication covering this subject is by Robert Hazen and James Trefil.
Well, in any case, how do you find Luca? There is the bottom-up approach, starting with early Earth conditions, and building up to Luca, or the top-down approach, using genomic data. You can also identify possible universal genes and assemble them into a Luca genome, sort of the Miller-Urey experiment brought up to date.
But you ask, like dinosaurs, why don’t scientists just measure the oldest living thing by carbon dating or something more advanced? Well, can’t be done for these microbeasts. Radiocarbon dating is good only for specimens younger than 60,000 years, plus anything billions of years old and that small is hard to find. Radiometric dating (measuring decay of radioactive isotopes like rubidium-strontium, with a half-life of 50 billion years) can go back to the beginning of time, but only for things like rocks.
After Luca, how did these single-cell organisms become animals and plants? There might have been an early start 30 million years before the Cambrian period, but, certainly, something happened 540 million years ago, when the Big Bang of biology created most multi-cellular life, in a relatively short period of 10 to 22 million years. Then came Lucy 3.2 million years ago and, finally, the at Dawn of Humanity, us, perhaps 200,000 years ago (scientist are guessing that Homo Sapiens appeared from 100 million to 300 million years ago), and most probably in Africa. There is, of course, that other biblical version, to again be explored in Chapter 5 of Book 2. Most Americans lean towards this second origin of Man.
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The Dow Jones Industrials increased 34 to 9320, with world markets mixed, but more down than up. Why is Ford doing so well? Their Focus is the number car purchased for clunkers. The Senate should tack on another couple of bills (make that billions) before they leave for their summer recess. Will Ford hit double digits by next quarter? The stock dropped to 1.01 on November 20, and is now at 8.32. Gold rose $9/toz to $966. (By the way, gold is sold in troy ounces, and you should remember that one troy ounce is 31.1 grams, while one "regular" ounce is 28.4 grams. Thus, when you buy gold, you get almost 10% more gold when you insist on troy weight.)
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Well, there are now Tropical Storm Enrique, with winds at 60 MPH, moving west-northwest at 16 miles per hour, and right behind, Tropical Storm Felicia at 45 MPH. There is a third disturbance that also lurks back there. Enrique, however, is projected to begin a more southernly than northerly path by Sunday and probably not trouble Hawaii. Felicia, however, appears to be currently predicted to approach the Big Island. I will be at the Mauna Kea Beach Hotel and Four Seasons from Sunday through Wednesday, so that could well get exciting.
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