CapitalistImperialistPig

Six million years ago a couple in Africa had two sons and their names were Cain and .... Let me try that again. Six million or so years ago there was a population of apes living in Africa who shared a lot of DNA (like 99%) with their surviving descendants, chimpanzees, bonobos and humans.  They probably looked a lot like those descendants, had brains about like chimps, were hairy like chimps and gorillas, and walked like them, but we really don't know because there is no trace of them in the fossil record.  Some of their offspring became chimps and bonobos, but we don't know much about their evolution since they didn't leave any trace in the fossil record for another 5 plus million years.  Other branches did start leaving traces a couple of millions of years later and they tend to be chimp sized, with chimp sized brains, but may have walked slightly more like humans. By about three million years ago some definitely upright walkers appeared.  They were still about...

The deepest mystery in biology, and in science generally, is the origin of life and the genetic code. Life as we know it cannot exist without DNA and the information it stores. But DNA and the genetic code cannot have come before life because it takes a vast and intricate system of molecular machines just to reproduce DNA and translate it into the proteins that do the actual business of metabolism and constitute the machinery of life, including all the machinery to turn DNA into protein. It's the chicken and egg problem in it's sharpest molecular form. DNA is not translated directly into protein. First it must be transcribed into messenger RNA, which in turn is translated into protein by a complex apparatus that consists of proteins and other kinds of RNA molecules. This fact is probably one element that suggested that maybe RNA was the molecule that came before gene and protein. Proteins are the most versatile components of our molecular machinery, acting as structural e...

One of the most mysterious questions in science is that of how the whole intricate apparatus of life arose in the first place.  All Earthly life is very much the same at the fundamental level, the vast chemical factory of the cell.  Three critical elements are the mechanism of information storage (DNA), the apparatus for translating the directions written in the DNA into proteins (RNA & proteins), and the proteins that do all the chemical and mechanical work of the cell.  None can carry out their function without the other two. Recent work has given us a clue, though.  RNA can't compete with proteins in general catalysis, but it does turn out to have some catalytic roles.  Most importantly, it turns out to be the RNA of the ribosome (rRNA) that does the all important task of catalyzing the formation of the peptide bond in the ribosome, the step that produces a protein out of amino acids. This strongly hints that RNA got there first.

... Meteorites ? Karen Hopkin in Scientific American: Because it appears that a rain of meteors nearly 4 billion years ago peppered the Earth’s exterior with precious metals. So says a study in the journal Nature. [Matthias Willbold, Tim Elliott and Stephen Moorbath, "The tungsten isotopic composition of the Earth’s mantle before the terminal bombardment"] When Earth was forming, molten iron sank to its center, creating the planet’s core. That iron carried with it a slew of iron-loving metals, including gold and platinum. In fact, the Earth’s core is packed with enough precious metals to cover the entire planet four meters deep. But not all that glitters is down at the planet’s center. Today there’s enough gold in the Earth’s rocky shell to please prospectors—and to puzzle planetary scientists: why is that gold not down in the core, too? The answer, it seems, is that it wasn’t even on the Earth until after the core formed. Isotope concentrations in rock samples of dif...

The religions of complex societies seem to be quite different from those of primitive societies.  In particular, these religions of the complex societies have gods that require worship and appeasement.  Moreover, they form much of the social glue that hold societies together.  New evidence from archeology clarifies how this process occurred.  Via Tyler Cowen , this National Geographic article by Charles C Mann lays out the case that organized religion predated agriculture: Göbekli Tepe, to Schmidt's way of thinking, suggests a reversal of that scenario: The construction of a massive temple by a group of foragers is evidence that organized religion could have come before the rise of agriculture and other aspects of civilization. It suggests that the human impulse to gather for sacred rituals arose as humans shifted from seeing themselves as part of the natural world to seeking mastery over it. When foragers began settling down in villages, they unavoidably created ...

Scientists have sequenced the DNA of extinct mammoths , and our Neandertal cousins are next. They are plotting to grow some: Scientists are talking for the first time about the old idea of resurrecting extinct species as if this staple of science fiction is a realistic possibility, saying that a living mammoth could perhaps be regenerated for as little as $10 million. Staple of SF or brilliant conception of Michael Crichton - I vote for the latter. About our cousin: The full genome of the Neanderthals, an ancient human species probably driven to extinction by the first modern humans that entered Europe some 45,000 years ago, is expected to be recovered shortly. If the mammoth can be resurrected, the same would be technically possible for Neanderthals. I'm as eager as the next nut to see a landscape populated by mammoths, dire wolves, and saber tooth tigers. Neandertals - not so much.

Andrew H. Knoll's Life on a Young Planet: The First Three Billion Years of Evolution on Earth is one of those rare books that can change your, or at any rate, my, picture of reality. I have posted twice before on this book: Eu are Irrelevant and In the Beginning , but the present post is my attempt at a review. Dinosaurs and mastodons don't wander through these pages, unless you count a cameo or two. Their time was still far in the future when the characters whose story is told here held center stage. The Cambrian Period, which started about 543 million years ago, or a bit less than ten thousand times as long ago as our own species originated, ushered in the Paleozoic Era and the first easily recognizable fossils. It was the first age of animals - not the very first animals, but the first animals with considerable size and complexity. All the animal phyla we now recognize were onstage in the Cambrian, as well as numerous phyla dead and gone. Before the Cambrian, only sponges,...