La historia de todo el pasado del universo [y de todo su futuro]

Kurzgesagt - In a Nutshell

microsiervos

Esta infografía animada es fruto de una colaboración especial de la gente de Kurzgesagt y de Wait but Why. Es una especie de repaso a nuestra historia al completo y a la de la vida en la tierra en general, un poco al estilo calendario cósmico aunque más bien lo hace utilizando incrementos temporales cada vez más grandes, de forma casi exponencial.

El resultado es perfecto porque a nivel gráfico es simple e icónico, con una elegancia sin igual. Además, las explicaciones son breves y precisas – e incluso quienes no dominen el inglés podrán usar la versión subtitulada al castellano. Además, las explicaciones que da son perfectamente fáciles de entender y con un genial toque de humor, como cuando dice que el ser humano más longevo (nacido a finales del XIX) está más cerca del imperio napoleónico que de la era actual, o que el Tiranosaurio Rex está más cerca en el tiempo del último concierto de Miley Cyrus que de su ancestro el Estegosaurio.

Si la gran parte del vídeo está dedicada a los 13.700 millones de años transcurridos desde el Big Bang, la parte final se dedica brevemente al fin de la Tierra, el Sistema Solar, las estrellas, los agujeros negros y con ello todo, la muerte térmica hasta el Fin de los Tiempos. Para siempre.

Estupendo material para pasar un rato embobado con las «distancias temporales» entre todo lo que conocemos, hacer un ejercicio de humildad acerca de nuestra nimia existencia en el Universo y estupendo material para compartir y charlar sobre él en clase, me atrevería a decir.

How Climate Change and Plate Tectonics Shaped Human Evolution

By Mark Maslin and The Conversation

It should not be a surprise that East Africa was a hotbed of evolution, because over the last five million years everything about the landscape has changed.

The extraordinary forces of plate tectonics and a changing climate have transformed East Africa from a relatively flat, forested region to a mountainous fragmented landscape dominated by the rapid appearance and disappearance of huge, deep-water lakes. And from this highly variable landscape emerged an ape smart enough to question its own existence.

A cradle rocked by tectonics
Twenty million years ago the Indian and Asian continental plates clashed and pushed up the massive Tibetan plateau. In summer this plateau acts as a huge heat engine, absorbing solar energy which it transfers to the atmosphere, causing immense convection currents. With all this hot air rising, air is sucked in from all round, including moist air from the Indian Ocean that produces intense South East Asian monsoons.

This has a knock on affect of drawing moisture away from the African continent, and it was this that began the progressive drying out of East Africa. In terms of human evolution, this distinct split between the climate of Asia and Africa coincides with the split between Asian and African apes, the latter eventually evolving into us.

At the same time as the peaks of Tibet were thrusting upwards, the rifting process began in Ethiopia and gradually moved south finishing in Mozambique about one million years ago. This rifting was caused by a hotspot of magma under northern East Africa heating the crust causing it to split down the middle like an overdone apple pie.

The rifting process produced a deep, wide, hanging valley half a mile above sea level with uplifted shoulders or mountain ranges on either side rising up to two miles high. The affects of the Rift Valley formation on the local climate was dramatic.

Keep reading on scientificamerican >>

Newly-Discovered Fossilized Skull Could Prove Homo Erectus Sole Human Ancestor

breitbart

By William Bigelow 

AFP

A new discovery of an ancient skull from an ancestor of humans has scientists backtracking from their earlier claims that separate species in Africa were the progenitors of the human race.

The skull, found in the Georgian villiage of Dmanisi, is roughly two million years old and is the only intact human ancestor’s skull ever found that dates from the early Pleistocene Era. Dmanisi has yielded bones thought to be the remains of three males, one of them elderly, a young female, and a child whose sex is indeterminate.

Christoph Zollikofer, a professor at Zurich University's Anthropological Institute, said, "Nobody has ever seen such a well-preserved skull from this period. This is the first complete skull of an adult early Homo. They simply did not exist before.” His awe was echoed by Tim White, from the University of California, Berkeley, who said, "The significance is difficult to overstate. It is stunning in its completeness. This is going to be one of the real classics in paleoanthropology." The Dmanisi bones are believed to be remnants of Homo erectus, the first ancestor who resembled modern humans and originated in Africa.

Zollikofer continued, "Everything that lived at the time of the Dmanisi was probably just Homo erectus. We are not saying that palaeoanthropologists did things wrong in Africa, but they didn't have the reference we have. Part of the community will like it, but for another part it will be shocking news."

The leader of the Dmanisi excavations, David Lordkipanidze, said, "If you found the Dmanisi skulls at isolated sites in Africa, some people would give them different species names. But one population can have all this variation. We are using five or six names, but they could all be from one lineage." Lordkipanidze theorized that the belief that Australopithecus sediba was a direct ancestor of humans was now probably wrong.

The consequences of the Dmanisi discovery could mean that species such as Homo rudolfensis, Homo gautengensis, Homo ergaster, and possibly Homo habilis would be dismissed.

White explained:

Some palaeontologists see minor differences in fossils and give them labels, and that has resulted in the family tree accumulating a lot of branches. The Dmanisi fossils give us a new yardstick, and when you apply that yardstick to the African fossils, a lot of that extra wood in the tree is dead wood. It's arm-waving.

But Chris Stringer, head of human origins at the Natural History Museum in London, took issue with the idea that Homo Erectus was solely responsible for the ancestry of humans, saying:

I think they will be proved right that some of those early African fossils can reasonably join a variable Homo erectus species. But Africa is a huge continent with a deep record of the earliest stages of human evolution, and there certainly seems to have been species-level diversity there prior to two million years ago. So I still doubt that all of the 'early Homo' fossils can reasonably be lumped into an evolving Homo erectus lineage. We need similarly complete African fossils from two to 2.5m years ago to test that idea properly.

Lee Berger, at the University of Witwatersrand, who discovered the species Australopithecus sediba, took issue with the conclusion drawn by the Dmanisis team. He said:

This is a fantastic and important discovery, but I don't think the evidence they have lives up to this broad claim they are making. They say this falsifies that Australopithecus sediba is the ancestor of Homo. The very simple response is, no it doesn't. What all this screams out for is more and better specimens. We need skeletons, more complete material, so we can look at them from head to toe. Any time a scientist says 'we've got this figured out' they are probably wrong. It's not the end of the story.

First face? Prehistoric fish was a jawdropper

By Jennifer Viegas/

The earliest known species with what we would recognize as a face was an armored, beady-eyed prehistoric fish, according to a new paper in the journal Nature.

The fish, entelognathus primordialis (meaning “primordial complete jaw”), is the oldest known animal to have face-forming jaw and cheek bones comparable to those of today’s bony fishes and most terrestrial animals, including us.

Keep reading at Fox News >>

Huge foreheads, flat faces and saucer-like eyes: How the human face might look in 100,000 years

Mail Online

Just as the human face has evolved considerably since stone age times so it is expected to keep changing in the future.

Today the human brain is three times the size of our primate ancestors. As our brains grew so did our heads get bigger, our skulls expanded and our features became flatter.

Now with the advent of wearable technology, such as Google Glass, how will our heads and faces evolve in 20,000 years, 60,000 years and even 100,000 years from now?

100,000 years: The human face will have evolved to be proportioned to the 'golden ratio,' with unnervingly large eyes featuring a sideways blink

2013: A typical man and woman

This was the question posed by artist and researcher Nickolay Lamm from MyVoucherCodes.co.uk when he quizzed Dr Alan Kwan, who holds a PhD in computational genomics from Washington University in St Louis. 

Based on their discussions Lamm has created a stunning series of images which display one possible evolution for the human race over the next 100,000 years.

Read more: http://www.dailymail.co.uk/news/article-2337804/Huge-foreheads-flat-faces-saucer-like-eyes-How-human-face-look-100-000-years.html#ixzz2cRGpATb0

World's oldest primate fossil discovered in China

ITN

Synthetic Biology and Conservation Biology Meet

phenomena

Listen:
Part 1 >>
Part 2 >>

Man's oldest ancestor identified as rat-sized mammal

itnnews

Hobbit Humans Come to Life With New Fossils

A reconstruction of a Hobbit face.

Susan Hayes, University of Wollongong

discovery

By Jennifer Viegas 

New bones attributed to Homo floresiensis -- aka the "Hobbit Human" -- along with other recent findings, are helping to reveal what members of this species looked like, how they behaved, and their origins.

The latest findings, described in a Journal of Human Evolution paper, are wrist bones unearthed on the Indonesian island of Flores. Since they are nearly identical to other such bones for the Hobbit found at the site, they refute claims that H. floresiensis never existed.

"The tiny people from Flores were not simply diseased modern humans," Caley Orr, lead author of the paper, told Discovery News.

"The new species of human stood approximately 3' 6" tall, giving it its nickname 'The Hobbit,'" continued Orr, who is an assistant professor in the Department of Anatomy at Midwestern University.

He said that they were "similar to modern humans in many respects." For example, he explained that they walked on two legs, had small canine teeth, and lived what appears to have been an iconic "cave man'" lifestyle.

"Stone tools and evidence of fire use were found in the cave, along with the remains of butchered animals, such as Stegodon (an extinct elephant relative), indicating that meat was a part of diet," Orr said.

He and his colleagues, however, also point out the differences between the Hobbit individuals and modern humans.

The Hobbits had arms that were longer than their legs, giving them a slightly more ape-like structure. Their skulls had no bony chins, so their faces had more of an oval shape. Their forehead was sloping. The inferred brain size was tiny, putting them in the IQ range of chimpanzees.

"Remarkably, the feet were also long relative to the legs, as fantasy fans might expect of a Hobbit," he added.

The Hobbit's wrist looked like that of early human relatives, such as Australopithecus, but the key ancestral candidate now is Homo erectus, "Upright Man."

It is possible that a population of H. erectus became stranded on the Indonesian island and dwarfed there over time. Orr said that "sometimes happens to larger animals that adapt to small island environments."

A problem, however, is that H. erectus is somewhat more modern looking than the Hobbit, so researchers are still seeking more clues.

Another question concerns whether or not the Hobbits ever mated with modern humans. There is evidence that happened to Neanderthals, which have left traces of their genome in modern human DNA. So far, however, conditions have not been right to extract DNA from H. floresiensis bones.

Nonetheless, the Hobbit -- which went extinct relatively recently during the Pleistocene -- is now better known due to the new discoveries.

"These fossils provide further, clear evidence that H. floresiensis is in no way a pathological modern human, or that its primitive morphology is related simply to its small body size," said Tracy Kivell, a paleoanthropologist from the Max Planck Institute for Evolutionary Anthropology. "Instead, it is clearly its own, unique and very intriguing species."

Kivell added, "What is particularly interesting is that H. floresiensis is associated with such a long, well-documented history of stone tools. (Its primitive hand and wrist were) still apparently capable of making and using stone tools, suggesting that H. floresiensis solved the morphological and manipulative demands of tool-making and tool-use in a different way than Neanderthals and ourselves."

Orr and his team continue to study the Hobbit humans, with at least one other paper about the interesting species in the works.

Darwin in Space: How Multigenerational Missions Could Shape Human Evolution

scientificamerican

Listen Here >>

“New environments inside this starship, for example, new radiation environments, whatever the gas composition is that people are breathing, whatever is the gravity field, those basic environmental conditions will reshape the human genome.”

That’s Cameron Smith. He’s an anthropologist at Portland State University who studies human evolution and prehistory. But he’s also very interested in the human future, including how space travel will impact the human race—both culturally and biologically. He wrote an article on the subject in the January issue of Scientific American, called “Starship Humanity.” He recently talked by phone with John Matson, host of our 60-Second Space podcast, about what might happen to a spacefaring humanity if we really were to take a star trek.

John Matson: This article that you’ve written for Scientific American, maybe you can just give us a brief overview of what the article is about.

Cameron Smith: You bet. So far the experience of humanity in space has been very limited. We have gone up for short periods of time, we’ve gone in very small numbers. But as space access becomes cheaper and more people start going up, eventually we’re going to have communities, we’re going to have populations of people up there. And then it shifts, our understanding of that is going to have to shift from purely biology to anthropology. These will be communities of people, and of course communities are cultural and they’re also biological. So anthropology marries culture and biology. And it will be used to help us plan out successful space colonization.

JM: Let’s say, just to set a scenario, a group of space travelers sets out on a multigenerational voyage to Alpha Centauri, where we now know that there is an exoplanet. What’s going to happen to these people on the way?

CS: Well, we can only predict that change will occur. We can make some predictions about some very few biological changes that might occur. But because mutation is random, and mutation is the origin of new characteristics in populations, because that is ultimately random, it’s not entirely possible to say precisely what will happen. What we can say, though, is that new environments—for example, new radiation environments, whatever the gas composition is that people are breathing, whatever is the gravity field inside this starship—those basic environmental conditions will reshape the human genome. Subtly, subtly, but they will reshape it.

We know that we have evolved under almost 15 pounds of pressure per square inch at sea level. And in the last few thousand years, though, some people have migrated to higher elevations, where they are under somewhat less pressure. Their biology has changed to account for that, or to make it possible to live there. They have different blood oxygen levels, they have deeper chests with greater what is called lung ventilation, greater capacity for breathing in and taking in oxygen. And even the biology of the developing infant is somewhat different. And I am certain that exactly the same sort of thing, on that same magnitude, will happen in off-Earth environments.

JM: What about weightlessness? Do we have any sense of what that would do to human physiology in terms of stature or size of human beings?

CS: Weightlessness is a big issue, and 30 years of almost continuous presence of humans in space—this is quite amazing—whether in Mir or the International Space Station or other stations, for 30 years somebody has been in Earth orbit almost continuously. What they have learned through that long period is that, yeah, weightlessness can have some pretty detrimental effects. Bone loss is one of them. Muscle is also reduced, but bone loss is a big one.

And so, I don’t think we’re going to try to do long-term space colonization in free-floating zero gravity. So we’ll go to places like Mars where there is one third, roughly, the gravity of Earth, and I think we’ll build these things that rotate and give us artificial—well, they give us gravity by rotating. You saw it in 2001: A Space Odyssey, the rotating space station. That works, and I think we’re going to be doing that for a much longer time than trying to actually live in zero or very small gravity.

But yes, it will have effects on the physiology as well. I was thinking of course in Mars, at one third, roughly, gravity, essentially in evolution, essentially if you can get away with something that costs less energy to do than your sibling, you have a selective advantage. And on Mars if you don’t require all of the muscle that a person does on Earth, where you have an extra two thirds gravity, then presumably you live in better health and have more offspring. So in the long term on Mars I think we will eventually see a lighter, lither build than on Earth.

JM: So the image of those spindly little green men is maybe not too far-fetched.

CS: Maybe so.

JM: Now, do we have a sense of how quickly these changes start to happen?

CS: The time scale for significant biological changes—yes, you can get them in a few centuries. You can start to see effects on the physiology in a number of centuries. This is the timescale that I’ve been working with. For example I’m in contact with a group in Germany called Icarus Interstellar. They’re devising propulsion systems to reach stars on the scale of several centuries. So I’ve been thinking about that scale as well—what kind of changes would we see in that kind of time frame? And some basic population genetics calculations that I’ve done, that concern what’s called time-to-fixation, and this is the spread of novel genes in a population.

And this suggests that yes, within a few centuries you could have changes on the order of different skin hues, or altered skin colors, different hair textures. But radical reshaping of the human body, for example. major stature differences or even new anatomical structures, those should take much, much longer. Those should take into the many thousands of years.

JM: There’s definitely a perception, especially in this country, in the U.S., that space exploration is on pause, that it’s ground to a halt. I happen to disagree with that, but it’s clear that no one is going to Alpha Centauri tomorrow. So why is it important to consider all these things now? Why is it important to think out all the implications of what space travel might mean?

CS: It’s absolutely important to start now because there’s so much to do. I mean, if we’re talking about long-term voyages, we’re talking about again, understanding things that we are just barely understanding today. For example, we have only in the last two decades got a high-resolution understanding of the human genome. And that helps us to understand human evolution, and evolution, it cannot be stopped. The only way to stop it is with extinction. And evolution of humanity is going to continue in space. And to prepare for it—again, you could do it without anthropology, but I don’t think it would survive. I don’t think it would work. So to do it with a good expectation of success, we need to think in long term. Well, what is the field that has given us a long-term understanding of humanity? That’s anthropology. Biology, relatively short-term, although it deals with evolution. But humanity, human evolution is somewhat different from most other evolution. And it's anthropology that has explored that. So, I think anthropology is going to be central to this.

JM: So as the physicists and engineers are working on propulsion systems and cosmic ray shielding, this is something that anthropologists should be working on in parallel, you believe?

CS: I believe absolutely we need to build an anthropology of space, an anthropology of space colonization. We know if we're going to spend generations in space that you have to prepare for the long term. Again, we think of it as people pop up there and they come back down. And the long-term view is, no, eventually, this will be migration. And this is part of the goal. Even just a few years ago NASA had a Vision Report that they released, which said that the essential mission of NASA was to better life here on Earth, to extend life there, that is, move some part of humanity to be able to live off of earth, and to find life beyond, that is exobiology. The interesting thing there is that in common in all three of those, what is common about those, it's not computers, it's not the technology, you need all of that, but what is common about those three statements is that it's about life. It's about living things. And living things change through time by evolution, and it's anthropology that has understood human evolution.

JM: You have a fairly recent book out about evolution.

CS: I have a book out now, a Popular Science book about human adaptation and space colonization, and in that my co-author and I are sketching out, it's an exploration, we're sketching out some of the kinds of ways that anthropology can assist us in making a success of space colonization. But right now I'm working on a technical book, it'll be a couple of years down the line, that again brings everything pertinent known from anthropology to the concept of space colonization, and hopefully that can be a foundation for a space anthropology.

JM: Now just to sort of wrap things up here, aside from the physics and the engineering of the actual spacecraft, what do you think will be the biggest challenge facing either the people who are putting together a crew for a long-duration spaceflight, or for the crew themselves?

CS: Well, one critique of this whole endeavor of space colonization and space activity by people in general is that, well, this isn’t going to fix humanity. We’re just going to transport our ancient problems off of the surface of the Earth. Well, I think so. Yeah, this isn’t meant to fix humanity. It is meant to give humanity an insurance policy. If the Earth is hit by a catastrophe, at least someone is left, if we are a several-planet species, for example.

The biggest challenge, I think they’ll be both biological and cultural. We don’t know how reproduction works in space. We also have to be very careful—we can’t just be ready to go and colonize space once we understand human biology in space and human evolution. We have thousands of plant and animal domesticates that are going to have to go with us. We can’t be eating canned food for generations. We have to ensure the health of those populations as well. That is why, you asked before, why start now? Well, there is a tremendous amount to do to think about all this.

So what will be the challenges? They will be both biological and cultural. We will have biological evolution happening—some of it will be painful. Much of that evolution will play out on those early stages of development. And there will be an increase, let’s say, in infant mortality. We’ll also have our same cultural baggage. We have ethnic rivalries, we have political differences, we have religious issues. I don’t think that’s going to go away. We should certainly take our best nature with us, but those things are rather ancient, and I think those will be as big a challenge as the biology.

Cameron Smith’s book, co-authored with Evan Davies is titled Emigrating Beyond Earth: Human Adaptation and Space Colonization. And Smith’s article "Starship Humanity" is in the January issue of Scientific American. A short preview is available free on the Web site, titled "How Humans Will Evolve on Multigenerational Space-Exploration Missions."

That’s it for this episode. Get your science news at our Web site, www.scientificamerican.com, where you can check out the In-Depth Report about Humanity’s Enduring Fascination with the Apocalypse. The so-called Mayan apocalypse is just the latest in a long line of doomsday predictions. And, ironically, it will not be the last. And follow us on Twitter, where you’ll get a tweet whenever a new article hits the Web site. Our Twitter name is @sciam. For Scientific American’s Science Talk, I’m Steve Mirsky, thanks for clicking on us.

An information-processing approach to the origin of life

kurzweilai

Is life based on software and information? (Plants in the Rwenzori Mountains, Uganda; credit: Wikimedia Commons)

A novel approach to the question of life’s origin, proposed by two Arizona State University scientists — Paul Davies, an ASU Regents’ Professor and director of the Beyond Center for Fundamental Concepts in Science, and Sara Walker, a NASA post-doctoral fellow at the Beyond Center — in an open-access Journal of the Royal Society Interface paper, attempts to dramatically redefine the problem.

The authors shift attention from the “hardware” — the chemical basis of life — to the “software” — its information content. They suggest that the crucial distinction between non-life and life is the way living organisms manage the information flowing through the system.

“We propose that the transition from non-life to life is unique and definable,” said Davies. “We suggest that life may be characterized by its distinctive and active use of information, thus providing a roadmap to identify rigorous criteria for the emergence of life. This is in sharp contrast to a century of thought in which the transition to life has been cast as a problem of chemistry, with the goal of identifying a plausible reaction pathway from chemical mixtures to a living entity.”

“Chemical based approaches,” Walker said, “have stalled at a very early stage of chemical complexity — very far from anything we would consider ‘alive.’ More seriously they suffer from conceptual shortcomings in that they fail to distinguish between chemistry and biology.”

“To a physicist or chemist life seems like ‘magic matter,’” Davies explained. “It behaves in extraordinary ways that are unmatched in any other complex physical or chemical system. Such lifelike properties include autonomy, adaptability and goal-oriented behavior — the ability to harness chemical reactions to enact a pre-programmed agenda, rather than being a slave to those reactions.

“We believe the transition in the informational architecture of chemical networks is akin to a phase transition in physics, and we place special emphasis on the top-down information flow in which the system as a whole gains causal purchase over its components, This approach will reveal how the logical organization of biological replicators differs crucially from trivial replication associated with crystals (non-life). By addressing the causal role of information directly, many of the baffling qualities of life are explained.”

Nonlocal biological functions

“The most important features of biological information (i.e. functionality) are decisively nonlocal,” the authors say. “Biologically functional information is therefore not an additional quality, like electric charge, painted onto matter and passed on like a token. It is of course instantiated in biochemical structures, but one cannot point to any specific structure in isolation and say “Aha! Biological information is here!”

The authors expect that, by re-shaping the conceptual landscape in this fundamental way, not just the origin of life, but other major transitions will be explained — for example, the leap from single cells to multi-cellularity.

“In all of these cases where appeal is made to an informational narrative, we encounter context- (state-) dependent causation. In this respect, biological systems are quite unlike traditional mechanical systems evolving according to fixed laws of physics.

“In biological causation, subject to informational control and feedback, the dynamical rules will generally change with time in a manner that is both a function of the current state and the history of the organism (suggesting perhaps that even the concept of evolution itself may be in need of revision.”

Life in non-organic substrates?

This perspective “forces new thinking in how life might have arisen on a lifeless planet, by shifting emphasis to the origins of information control, rather than — for example — the onset of Darwinian evolution or the appearance of autocatalytic sets (i.e. either analog or digital that lack information control), which, although certainly important to the story of life’s emergence, do not rigorously define how/when life emerges as a function of chemical complexity.

“It also permits a broader view of life, where the same underlying principles would permit understanding of living systems instantiated in different chemical substrates (including potentially non-organic substrates). …

“Purely analog life-forms could have existed in the past but are not likely to survive over geological timescales without acquiring explicitly digitized informational protocols. Therefore life-forms that ‘go digital’ may be the only systems that survive in the long-run and are thus the only remaining product of the processes that led to life.

“As such, the onset of Darwinian evolution in a chemical system was likely not the critical step in the emergence of life. … Instead, the emergence of life was likely marked by a transition in information processing capabilities. This transition should be marked by a reversal in the causal flow of information from bottom-up only to a situation characterized by bi-directional causality.

“Characterizing the emergence of life as a shift in causal structure due to information gaining causal efficacy over matter marks the origin of life as a unique transition in the physical realm.”

Hallmarks of life

The authors suggest these specific hallmarks of life:

• Global organization
• Information as a causal agency
• Top-down causation
• Analog and digital information processing
• Laws and states co-evolve
• Logical structure of a universal constructor
• Dual hardware and software roles of genetic material
• Non-trivial replication
• Physical separation of instructions (algorithms) from the mechanism that implements them

Walker is also affiliated with the NASA Astrobiology Institute in Mountain View, Calif. and the Blue Marble Space Institute, Seattle.

References:

• Sara Imari Walker and Paul C.W. Davies, The Algorithmic Origins of Life, Journal of the Royal Society Interface, 2013, DOI: 10.1098/​rsif.2012.0869 (open access)

Who Didn't Have Sex with Neanderthals?

Discovery news

Charles Choi, LiveScience Contributor

spiegel.de

The only modern humans whose ancestors did not interbreed with Neanderthals are apparently sub-Saharan Africans, researchers say.

New findings suggest modern North Africans carry genetic traces from Neanderthals, modern humanity's closest known extinct relatives.

Although modern humans are the only surviving members of the human lineage, others once roamed the Earth, including the Neanderthals. Genetic analysis of these extinct lineages' fossils has revealed they once interbred with our ancestors, with recent estimates suggesting that Neanderthal DNA made up 1 percent to 4 percent of modern Eurasian genomes. Although this sex apparently only rarely produced offspring, this mixing was enough to endow some people with the robust immune systems they enjoy today.  More >>

Why Societies Develop Like Embryos: The God Problem

PJMedia/ By Howard Bloom

An exclusive excerpt from chapter 6 of the new science/history/philosophy nonfiction book The God Problem: How A Godless Cosmos Creates, the new offering from the author of The Lucifer Principle: A Scientific Expedition into the Forces of History, Global Brain: The Evolution of Mass Mind from the Big Bang to the 21st Century and The Genius of the Beast: A Radical Re-Vision of Capitalism.

The God Problem: How A Godless Cosmos Creates is published on August 24 and is now available for pre-order on Amazon.

****

The Zygote Snabs Herbert Spencer

Meanwhile, in 1851, when he is thirty-one years old and walking, talking, and singing with Miss Evans, Herbert Spencer runs across an idea that will make him one of the biggest big-picture thinkers of all time. It is the idea that will keep Spencer a bachelor married to only one thing, his grand “synthesis.” Herbert Spencer will come across von Baer’s principle that cells in an embryo start out looking pretty much alike, then get more and more unique to their species. And more and more specialized in their function. Von Baer’s principle will change Spencer’s thinking. It will become the key to Spencer’s grand unification. And to his view of evolution. It will become Herbert Spencer’s equivalent to Newton’s gravity.

Yes, differentiation and the metaphor of the embryo will enter Herbert Spencer’s thinking three years after he comes to the Economist and one year after he begins to frequent John Chapman’s soirees. Says Spencer, “In 1851, I became acquainted with von Baer’s statement that the development of every organism is a change from homogeneity to heterogeneity.” And that acquaintance will push Spencer to till the soil in which Charles Darwin will plant a seed.

Once Herbert Spencer is exposed to von Baer’s work, the embryologist’s influence will show up almost instantly in Spencer’s work. It is the grand unifying principle that Spencer has been hunting for. It is another unifying principle to add to what Spencer has taken from George Henry Lewes’s explanations of Comte—the principle of evolution, and the principle that evolution constantly churns out something that Spencer calls “progress.” So von Baer’s principle of differentiation becomes central to Spencer’s 1851 first book, Social Statistics. The bigger and the more advanced the society, Social Statistics says, the more differentiation, the more specialization. The more “‘distinct classes’ and ‘special occupations.’” Large-scale societies unfold like embryos. They evolve like zygotes in the womb. Spencer publishes Social Statistics eight years before the publication of the book in which Charles Darwin premiers his theory of evolution, the Origin of Species. But Spencer, like the other habitués of Chapman’s get togethers, is already an evolutionary thinker, and he portrays the differentiation of human societies as an evolutionary process. Again, the word evolution has not appeared even once in Darwin’s only published book, his Voyage of the Beagle. But it appears one hundred times in Spencer’s second book, his 1855 Principles of Psychology. A book that comes out four years before Darwin’s On the Origin of Species.

Here’s how the combination of evolution and von Baer’s differentiation works. Says Spencer, in early societies, everyone did everything—hunting, fishing, and tool and weapon making. But as societies evolved, some men specialized in hunting and fishing and others became full-time tool or weapons makers—full-time spear and fishing hook experts. Way, way down the line, really advanced societies invented machines like railroad engines with hundreds of parts. So in an advanced society, there might be a specialist in Swindon who zeroed in on nothing but hand-making the setscrews for the steam engine, a task so exacting that one real-life machinist of Spencer’s day said “it almost made me sick.” Meanwhile other specialists assembled the engine, tested it, and ran it. And yet more specialists raised fruits, veg- etables, cows, and pigs and sent them into the city via railroad to feed the setscrew specialist. At the same time, even more specialists raised cotton in the American South, carded it and combed it in Manchester, then ran the resulting thread through Manchester’s weaving machines to make the set- screw maker’s clothes.

The result? Says Spencer, societies are like organisms. And their advance toward higher levels of complexity is like “the development of an embryo or the unfolding of a flower.” Yes, societies unfold like flowers or embryos:

Hence it happens that a tribe of savages may be divided and subdivided with little or no inconvenience to the several sections.

More >>

Biological clock began ticking 2.5 billion years ago

By Debora MacKenzie

OUR core physiology relies on subtle organic timers: disrupt them, and effects range from jet lag to schizophrenia. Exactly how and when life began keeping time is unclear, but a candidate for the original biological clock may solve the mystery.

Biological clocks are ubiquitous in nature, so the first clock should pre-date the evolutionary parting of the ways that led to modern groups of organisms. All the clocks found so far are unique to different groups of organisms, though. Not so the clock discovered by Akhilesh Reddy at the University of Cambridge and colleagues. In an enzyme called peroxiredoxin (PRX), they seem to have found a grandfather clock - one that is common to nearly all life.

PRX gets rid of poisonous, highly reactive oxygen (ROS), which is produced by oxygen-based metabolism. And the enzyme oscillates: it flits between an active and inactive state, depending on whether oxygen is bound to the active site. Using antibodies that bind only to the oxidised enzyme, the team found that PRX oxidation keeps cycling independently on a 24-hour cycle, even when organisms were kept in constant light or constant dark.

Moreover, they found this PRX cycle in mice, fruit flies, a plant, a fungus, an alga, bacteria and even in archaea - the most primitive of all cellular life (Nature, DOI: 10.1038/nature11088). That suggests PRX evolved early in life's history. A gene sequence analysis suggests it did so 2.5 billion years ago, during the Great Oxygenation Event (GOE) - a critical interval when the oxygen released by photosynthesis began to accumulate in the atmosphere.

Reddy thinks PRX protected primitive cells from ROS damage by surging when peaks in photosynthesis related to daylight temporarily bumped up levels of oxygen. "Initially this was externally driven," he says. Then PRX began oscillating spontaneously in anticipation of this load - thus becoming an independent daily clock. "Organisms with this anticipatory ability would be better adapted than organisms that merely 'reacted' to things as they happened," Reddy says.

Because all forms of life appear to dance to the metabolic rhythm of PRX oxidation, Reddy believes it pre-dates the other gene-related clocks that organisms carry.

It may even have driven their evolution. A gene-related clock, unique to cyanobacteria, appears to have evolved alongside PRX. What is more, another archaean that lives without oxygen and never had to deal with ROS has no PRX clock - and no circadian rhythms at all.

When PRX emerged 2.5 billion years ago, the Earth spun faster and a day lasted only 11 hours. "It will have adapted to the lengthening of the day-night cycle over time," says Reddy.

It may have done more than adapt - day lengths best suited to biological clocks may have coincided with times during which life made important evolutionary leaps. Ioannis Karafyllidis of the Democritus University of Thrace in Xanthi, Greece, has found that the cycling of the cyanobacterial clock resonates, or works most efficiently, at periods of 11 and 21 hours. These are the day lengths of the GOE and the Cambrian explosion of life, around 530 million years ago (Biosystems, DOI: 10.1016/j.biosystems.2012.02.008).

The Evolution of Grandparents

During the summer of 1963, when I was six years old, my family traveled from our home in Philadelphia to Los Angeles to visit my maternal relatives. I already knew my grandmother well: she helped my mother care for my twin brothers, who were only 18 months my junior, and me. When she was not with us, my grandmother lived with her mother, whom I met that summer for the first time. I come from a long-lived family. My grandmother was born in 1895, and her mother in the 1860s; both lived almost 100 years. We stayed with the two matriarchs for several weeks. Through their stories, I learned about my roots and where I belonged in a social network spanning four generations. Their reminiscences personally connected me to life at the end of the Civil War and the Reconstruction era and to the challenges my ancestors faced and the ways they persevered.
My story is not unique. Elders play critical roles in human societies around the globe, conveying wisdom and providing social and economic support for the families of their children and larger kin groups. In our modern era, people routinely live long enough to become grandparents. But this was not always the case. When did grandparents become prevalent, and how did their ubiquity affect human evolution?

Flannery on #Evolution: Competition Leads to Cooperation

Paleontologist Tim Flannery reminds listeners that while evolution functions as a competitive mechanism, the mutually dependent relationships that it produces should not be taken for granted. "The mechanism is pretty nasty and brutish," he says. "The legacy -- the thing it gives rise to -- is an enormously cooperative world."

 

The Evolutionary Errors of #X-Men

By John Rennie

In X-Men: First Class, the latest film about the popular comic book superheroes, one of the mutant characters goes by the nickname Darwin because he has the power of "reactive evolution." He instantly adapts to any threat: toss him in water and he sprouts gills; hit him with a club and his skin turns to armored plates.

Biology mavens in the audience may object that this form of evolution is more or less the opposite of what Charles Darwin proposed with his theory of natural selection. If anything, the mutant’s abilities are more in line with the rival, disproved theories of Jean-Baptiste Lamarck, who argued for the heritability of acquired characteristics. But maybe the name "Lamarck" would sound too much like a maitre d' rather than a mutant to fans.

Full story...

El cactus que caminaba

Medía unos seis centímetros de largo, tenía el cuerpo blando como un gusano, diez pares de espinas robustas y probablemente apéndices articulados. Esa extraña criatura que se parecía más a una planta que a un animal pudo ser hace 500 millones de años el antepasado de los artrópodos modernos -animales con patas articuladas, como las arañas y los crustáceos-, el grupo biológico que ha tenido más éxito en el mundo animal. Los científicos han bautizado a esta forma de vida desconocida hasta ahora como el «cactus caminante», por su apariencia vegetal y los fuertes miembros sobre los que conseguía desplazarse. Su descripción aparece detallada por primera vez en la revista «Nature».

El cactus que caminaba

Global warming may reroute evolution

February 16, 2011

The common milkweed (Asclepias syriaca) being eaten by a monarch caterpillar (Danaus plexippus). Credit: Rachel Vannette

(PhysOrg.com) -- Rising carbon dioxide levels associated with global warming may affect interactions between plants and the insects that eat them, altering the course of plant evolution, research at the University of Michigan suggests.

 Full story

Global warming may reroute evolution