Posts Tagged ‘homo sapiens’
“Homo sapiens, the only creature endowed with reason, is also the only creature to pin its existence on things unreasonable”*…
How, Sarah Constantin asks, did we humans get so smart?
If you zoom way out and look at the history of life on Earth, humans evolved incredibly recently. The Hominidae — the family that includes orangutans, chimpanzees, bonobos, gorillas, and humans — only arose 20 million years ago, in the most recent 0.5% of evolutionary history.
Within the Hominidae, in turn, Homo sapiens is a very recent development [see image at top]. We appeared 800,000-300,000 years ago, or in the last 1.5%-5.3% of hominid history.
If you look at early hominid “technological” milestones like tool use or cooking, though, they’re a lot more spread out over time. That’s interesting.
There’s nothing to suggest that a single physical change in brains should have given us both tool use and fire, for instance; if that were the case, you’d expect to see them show up at the same time.
Purposeful problem-solving behaviors like tool use and cooking are not unique to hominids; some other mammals and birds use tools, and lots of vertebrates (including birds and fish) can learn to solve puzzles to get a food reward. The general class of “problem-solving behavior” that we see, to one degree or another, in many vertebrates, doesn’t seem to have arisen surprisingly fast compared to the existence of animals in general.
However, to the extent that Homo sapiens has unique cognitive abilities, those did show up surprisingly recently, and it makes sense to privilege the hypothesis that they have a common physical cause.
So what are these special human-unique cognitive abilities?…
“Is Human Intelligence Simple? Part 1: Evolution and Archaeology,” from @s_r_constantin. Part 2 is here.
* Henri Bergson
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As we study our species, we might send self-examining birthday greetings to Giambattista Vico; he was born on this date in 1668. A political philosopher, rhetorician, historian, and jurist, Vico was one of the greatest Enlightenment thinkers. Best known for the Scienza Nuova (1725, often published in English as New Science), he famously criticized the expansion and development of modern rationalism and was an apologist for classical antiquity.
He was an important precursor of systemic and complexity thinking (as opposed to Cartesian analysis and other kinds of reductionism); and he can be credited with the first exposition of the fundamental aspects of social science (and so, is considered by many to be the first forerunner of cultural anthropology and ethnography), though his views did not necessarily influence the first social scientists. Vico is often claimed to have fathered modern philosophy of history (although the term is not found in his text; Vico speaks of a “history of philosophy narrated philosophically’). While he was not strictly speaking a historicist, interest in him has been driven by historicists (like Isaiah Berlin).
“Oh how wrong we were to think immortality meant never dying”*…
The John Templeton Foundation has undertaken a undertaken a deep investigation into the biology, philosophy, and theology of immortality research. Lorraine Boissoneault offers the first in a series of reports on their work…
Around 100,000 years ago, humans living in the region that would come to be called “Israel” did something remarkable. When members of the community died, those left behind buried the dead in a cave, placing some of the bodies with great care and arranging them near colorful pigments and shells. Although burial is so common today as to be almost unremarkable, for ancient humans to exhibit such behavior suggested a major development in cultural practices. The Qafzeh Cave is one of the oldest examples that humans understand death differently than many other creatures. We seem to have an innate desire to mark it with ritual.
It is an unavoidable fact of biology that all organisms die, whether by disease, disaster, or simply old age. Yet our species, Homo sapiens, seems to be the only creature blessed—or cursed—with the cognitive ability to understand our mortality. And thanks to our powerful intelligence, we’re also the only beings to imagine and seek out death’s opposite: immortality.
In religious traditions, spiritual afterlives and reincarnation offer continuation of the self beyond death. In myth and legend, sources of everlasting life abound, from the Fountain of Youth to elixirs of life. Some people seek symbolic immortality through procreation. Others aim for contributions to society, whether artistic, academic or scientific. And still others have pushed the bounds of technology in search of dramatic life extension or a digital self.
Where does this impulse come from?…
Find out: “Pre-life, Afterlife, and the Drive for Immortality,” from @boissolm @templeton_fdn.
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As we internalize eternity, we might recall that it was on this date in 1826 that the HMS Beagle set sail from Plymouth on its first voyage, an expedition to conduct a hydrographic survey of Patagonia and Tierra del Fuego in support of the larger ship HMS Adventure.
The Beagle‘s second voyage (1831-1836) is rather better remembered, as it was on that expedition that the ship’s naturalist, a young Charles Darwin (whose published journal of the journey, quoted above, earned him early fame as a writer) made the observations that led him to even greater fame for his theory of evolution.
“We are a species which is naturally moved by curiosity, the only one left of a group of species (the genus Homo) made up of a dozen equally curious species”*…
… and one thing that curiosity might lead us to wonder is where evolution might take humanity from here. As Nick Longrich points out…
Discussions of human evolution are usually backward looking, as if the greatest triumphs and challenges were in the distant past. But as technology and culture enter a period of accelerating change, our genes will too. Arguably, the most interesting parts of evolution aren’t life’s origins, dinosaurs, or Neanderthals, but what’s happening right now, our present – and our future.
He reasons to some fascinating possibilities…
Humanity is the unlikely result of 4 billion years of evolution.
From self-replicating molecules in Archean seas, to eyeless fish in the Cambrian deep, to mammals scurrying from dinosaurs in the dark, and then, finally, improbably, ourselves – evolution shaped us.
Organisms reproduced imperfectly. Mistakes made when copying genes sometimes made them better fit to their environments, so those genes tended to get passed on. More reproduction followed, and more mistakes, the process repeating over billions of generations. Finally, Homo sapiens appeared. But we aren’t the end of that story. Evolution won’t stop with us, and we might even be evolving faster than ever.
It’s hard to predict the future. The world will probably change in ways we can’t imagine. But we can make educated guesses. Paradoxically, the best way to predict the future is probably looking back at the past, and assuming past trends will continue going forward. This suggests some surprising things about our future…
Meet our future selves: “Future evolution: from looks to brains and personality, how will humans change in the next 10,000 years?“– @NickLongrich in @ConversationUS.
* Carlo Rovelli, Seven Brief Lessons on Physics
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As we ponder the possible, we might send insightful birthday greetings to Richard Dawkins; he was born on this date in 1947. An evolutionary biologist, he made a number of important contributions to the public understanding of evolution. In his 1976 book The Selfish Gene, he popularized the gene-centred view of evolution and introduced the term meme. In The Extended Phenotype (1982), he introduced the influential concept that the phenotypic effects of a gene are not necessarily limited to an organism’s body, but can stretch far into the environment. And in The Blind Watchmaker (1986), he argued against the watchmaker analogy, an argument for the existence of a supernatural creator based upon the complexity of living organisms; instead, he described evolutionary processes as analogous to a blind watchmaker, in that reproduction, mutation, and selection are unguided by any designer.
“Human nature scares the hell out of me”*…
Henry Gee, paleontologist and senior editor of Nature, argues that we Homo sapiens are setting ourselves up for collapse. He cites population decline, a lack of genetic variation, our socioeconomic fixation on growth (and the way that that’s plundered the planet), among other factors. But he singles out one phenomenon in particular…
The most insidious threat to humankind is something called “extinction debt.” There comes a time in the progress of any species, even ones that seem to be thriving, when extinction will be inevitable, no matter what they might do to avert it. The cause of extinction is usually a delayed reaction to habitat loss. The species most at risk are those that dominate particular habitat patches at the expense of others, who tend to migrate elsewhere, and are therefore spread more thinly. Humans occupy more or less the whole planet, and with our sequestration of a large wedge of the productivity of this planetwide habitat patch, we are dominant within it. H. sapiens might therefore already be a dead species walking.
The signs are already there for those willing to see them. When the habitat becomes degraded such that there are fewer resources to go around; when fertility starts to decline; when the birth rate sinks below the death rate; and when genetic resources are limited—the only way is down. The question is “How fast?”…
Eminently worth reading in full: “Humans Are Doomed to Go Extinct,” from @EndOfThePier in Scientific American (@sciam).
For chorus effect, see also “Headed for a sixth mass extinction? MIT geophysicist warns oceans are on the brink.”
And for a look at the (possible) aftermath, explore “The Earth After Humans.”
* Neil deGrasse Tyson
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As we remind ourselves that “hope is a discipline,” we might send expansively-creative birthday greetings to Freeman Dyson; he was born on this date in 1923. A theoretical and mathematical physicist, mathematician, and statistician, he made material contributions– both processes and concepts— in quantum field theory, astrophysics, the mathematical formulation of quantum mechanics, condensed matter physics, nuclear physics, and engineering.
He will forever be remembered by SciFi fans as the originator of the idea of (what’s called) the Dyson Sphere (or Dyson Shell): he proposed that a highly advanced technological civilization would ultimately completely surround its host star with a huge shell to capture 100% of the useful radiant energy. This Dyson Sphere would have a gigantic cluster of artificial planetoids (“Dyson cloud”) with billions of billions of inhabitants who would make use of the energy captured by the Dyson Sphere. He also made the intriguing speculation that a Dyson Sphere viewed from other galaxies would have a highly distinctive, unnatural light. He suggested astronomers search for such tell-tale colored stars, which should signify advanced, intelligent life.
Dyson was skeptical of some climate science, believing that the advantages of global warming (e.g., greater crop yields) were underweighted and that climate models were underdeveloped (and thus untrustworthy). Still he sounded the alarm (in a way resonant with Gee’s, above) as to the possibility of humanity poisoning its own future:
In the near future, we will be in possession of genetic engineering technology which allows us to move genes precisely and massively from one species to another. Careless or commercially driven use of this technology could make the concept of species meaningless, mixing up populations and mating systems so that much of the individuality of species would be lost. Cultural evolution gave us the power to do this. To preserve our wildlife as nature evolved it, the machinery of biological evolution must be protected from the homogenizing effects of cultural evolution.
Unfortunately, the first of our two tasks, the nurture of a brotherhood of man, has been made possible only by the dominant role of cultural evolution in recent centuries. The cultural evolution that damages and endangers natural diversity is the same force that drives human brotherhood through the mutual understanding of diverse societies. Wells’s vision of human history as an accumulation of cultures, Dawkins’s vision of memes bringing us together by sharing our arts and sciences, Pääbo’s vision of our cousins in the cave sharing our language and our genes, show us how cultural evolution has made us what we are. Cultural evolution will be the main force driving our future…
“Biological and Cultural Evolution– Six Characters in Search of an Author”
“In the landscape of extinction, precision is next to godliness”*…
There is a portion of the sky where no spacefarer wants to go. It causes Astronauts to see shooting stars in front of their eyes, sets off emergency sensors and renders satellites useless. This Bermuda Triangle of space isn’t just a cause for concern for our future of space exploration, it could be the sign of something far more deadly. This may herald an event that last happened 42,000 years ago, which wiped out our closest relative, the Neanderthals. Welcome to the terrifying world of the South Atlantic Anomaly.
In the 80s engineers noticed that most satellite errors happened over South America and the South Atlantic. These errors ranged from minor glitches, wiped data to full-blown crashed satellites. But they couldn’t quite pinpoint what was causing these troubling errors, they named this mysterious area the South Atlantic Anomaly (SAA).
We didn’t understand the dangers of this region for a long time. When the Hubble Space Telescope first turned on in 1990 they found that the computers kept crashing and data was corrupted almost every time it flew over the South Atlantic. Not wanting their billion-dollar telescope to crash to Earth, the engineers had no choice but to switch it off every time it passed over this deadly patch of sky, and still do today. Not ideal, but it saves the telescope from this mysteriously dangerous part of space.
So what makes the South Atlantic Anomaly so dangerous? It turns out it is all down to the Sun and a crack in Earths armour caused some very bizarre geophysics.
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So what does struggling satellites means for us here on Earth? Well, quite a lot really. It could be a sign of something much more deadly, a geomagnetic reversal.
When we picture the Earth’s magnetic field we often think of it as unchanging. It is our eternal armour from deadly solar radiation as well as the guide for our sailors. Even some birds have evolved iron-rich cells in their eyes, enabling them to ‘see’ the magnetic field and navigate the globe. But the magnetic north pole hasn’t always been in the north.
The magnetic poles have flipped repeatedly over the millennia. The field weakens, disappears and then reappears in the opposite direction. We know this because iron-rich lava aligns to the magnetic field and then sets, so we can look at ancient rocks and see what direction magnetic north was when it formed.
We don’t have a complete understanding of how the magnetic field is generated and why it flips. We know that convection currents of iron-rich mantle create the field, but the interactions between these immense systems are complex and hidden from us. What’s more, there are no patterns to the past flipping events, so it is very hard to predict when one will happen.
But, models and simulations show that when the field gets weaker at the beginning of a magnetic flip, it seems to happen in a random area and then grows from there. The poles also start to drift quite dramatically and chaotically. This is worrying because not only does the South Atlantic Anomaly look like the weakening in a simulation, it is also growing, and the North pole is drifting further each year.
… So, it seems at least plausible that the South Atlantic Anomaly is the start of the next geomagnetic flip. If so, it could have enormous consequences for us!
The last time a flip happened was 42,000 years ago, but it was only a temporary event, and the poles returned to their previous locations, this is known as the Laschamps Excursion, and it lasted for about a thousand years. That meant Earth was without its essential protective shield for an awfully long time.
Now, 42,000 years ago is a significant time. This was when Neanderthals died out. We (Homo Sapiens) also started using caves, red ochre body paint, and the global craze of cave painting started. It was also when a lot of ice-age megafauna died out. All of which has been linked to the flipping of the poles during this period. This extinction event and Sapien revolution has been called the Adams Event (after Douglas Adams and the infamous 42).
This theory suggests that when the poles flipped, the Earth had a thousand years without its protective layer, so the planet was bombarded with radiation. This depleted ozone, increased radiation on the surface, messed with weather patterns and caused abrupt climate change.
Scientist even suggests that this is why we suddenly took to living in caves and using red ochre. We had to hide from the deadly rays of the Sun, and if we ventured out, we needed a powerful suncream, like powdered red ochre. This is why red ochre hand paintings became so widespread around this time.
But these immense changes hit one species particularly hard. Neanderthals were likely red-headed, light-skinned and mostly dwelt in steppes (grassy plains) and woodlands. They probably got sunburnt a lot. Unlike Homo Sapiens, it seems as though Neanderthals didn’t use red ochre much at all! All of this means that cancers would have been a deadly problem for them.
To make all this even worse, the radiation increased the strength of electrical storms, changed the weather patterns and screwed up many ecosystems. So the food that the Neanderthals hunted my have been driven away or gone extinct. It seems Neanderthals died out because they starved to death while being baked by the Sun. Meanwhile, we Homo Sapiens hid from the Sun, used weird sunscreen and adapted to new foods…
These flipping events take hundreds or thousands of years to pass due to the amount of heavy magma that needs to shift to cause a flip (however it is hypothesised it could take as little as a month in extreme circumstances). So we aren’t in any danger of waking up to a new direction for North. But, over the next few decades or hundreds of years, we will see the South Atlantic Anomaly grow and potentially be joined by many other areas of weak magnetism. We may even see some local flips in a few hundred years.
So, it seems at least plausible that the South Atlantic Anomaly is the start of the next geomagnetic flip. If so, it could have enormous consequences for us!
The South Atlantic Anomaly: Earth’s deadly weakness: “Do Failing Satellites Foretell An Imminent Extinction?” From Will Lockett (@welockett).
* Samuel Beckett
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As we search for true north, we might send charged birthday greetings to a man whose life work could be at risk if there’s a flip (or an intense solar storm), Elihu Thomson; he was born on this date in 1853. An engineer and inventor, he was instrumental in developing the practical applications of electricity, especially alternating current. He invented electric welding and other important advances in electric lighting and power (among his lifetime total of about 700 patents). Thomson was also a cofounder of the General Electric Company (in 1892, in a merger of his Thomson-Houston Electric Company with the Edison Company.
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