Posts Tagged ‘life origins’
on religion and explanation
it’s true
Jacinta: I’ve been thinking about religion as the earliest form of explanation for a while, and about when we – our species, or our ancestors – began to feel the need for explanations, about everyday regularities and irregularities, such as why the blinding white disc travels across the sky, disappears, plunging the world into darkness, then reappears on the opposite side and retraverses the sky again. And again and again. Or why these periods of light are sometimes warmer, sometimes cooler. Or why water pours from the sky from time to time. Or why, in the darkness, there are patterns of tiny white lights in the sky, together with a much larger pale white disc that seems to be slowly eaten away to nothing then replenished over a period of many ‘days’ and ‘nights’. What were these things, and why did the ‘air’ around us whizz by, sometimes with such force as to blow the trees down and blow our children off their feet and make them cry.
Canto: Hmm. Dogs and cats certainly don’t seem to wonder about such things. What about bonobos? They certainly display curiosity. I’ve seen monkeys crowd around an exotic animal, poking and prodding and jumping away when they get a reaction, just as I’ve seen the forest people of the Congo crowding around a white man, something completely new in their lives.
Jacinta: Yes isn’t the internet a grand thing for the armchair-bound. That sort of curiosity, as you say, is for new things, and it is on display in cats and dogs. And the questions for them are – can I eat it? Is it dangerous? But the queer regularities that have been with all these creatures from the beginning – night and day, warmth and cold, rain and shine, earth and sky – it seems unlikely that any dog or cat has felt curious about such things. Bonobos I’m not so sure about, but I’m doubtful. At some stage in our ancestry, and it would be obviously linked to neural development, we started asking ourselves – why is this happening?
Canto: Language. To ask these questions, even of ourselves, wouldn’t we need language?
Jacinta: Hmmm. Maybe. But imagine some highly irregular natural event, like a solar eclipse, being experienced by our pre-lingual ancestors, whether Homo erectus or an Australopithecine. They’d be shocked, scared, and they’d be hanging together, maybe huddling together, communicating their fear, and maybe their wonder.
Canto: Thinking mostly, is it dangerous? Should we hide? And even with language, with a singular event like that, they wouldn’t have an explanation.
Jacinta: Well, they might have a go at an explanation – okay, maybe you’re right, maybe some kind of language would be necessary, which is kind of the same thing as neural development. I mean, language clearly didn’t just come about, it evolved, over who knows how long. And we still don’t know if Neanderthals had it, or some rudimentary version of it, like us, 100,000 years ago or whatever. Think of fire. Once someone learned how to create and control it, and utilise it for warmth and to ward off predators, and, presumably later, to transform our food, they needed to communicate these skills. And from there, or somewhere, they might go on to communicate other things, like navigating by the stars, or how those stars crossed the sky, like human travellers crossing the land in search of food. Stories, of a kind.
Canto: So, I’ve been investigating a bit more, and there’s been some observed behaviours in chimps – and clearly they don’t have language, unless you define language very widely – that some have described as proto-ritual, such as slow-dancing in the face of fires. Fires caused by thunderstorms would be a highly irregular feature of life for chimps, living half in savannah grasslands, half in forests. And ‘dancing’, or ritual movements, might be a way of trying to placate or somehow communicate with this apparently living, dangerous force. And they’ve also been observed performing such ‘dances’ when the rain pours down.
Jacinta: Hmmm, and those movements might be meant to convey something to the fire or rain, or some other phenomenon, but also to other chimps. Something about communicating to others that there’s maybe a way to deal with these phenomena. This might hardly be in the realm of proto-proto religion, but surely the first religions were animistic – according significance and even some kind of intention to the wind and rain, thunder and lightning, lakes and streams, hills and valleys, specific trees and so on.
Canto: Yes, much fuss has been made of a tree hollow in which chimps were found placing stones, for no non-ritualistic purpose human observers could think of. If nothing else, it indicates that the more we observe other species, the more complex and multi-faceted they tend to become. Remember when we used to talk about bird-brains?
Jacinta: I also saw, on a video, that during a firestorm one of the chimps, apparently a king-pin, appeared to be raging at the fire, seeming to suggest that he – it would surely be a male, given chimp society – could, or thought he could, tame the beast, like old George slaying the dragon. Intimations of future shamanism?
Canto: Yes, or maybe he was just pissed off after a fight with the missus. Jane Goodall, on noting chimpanzees sitting for a long time staring ‘dreamily’ at a waterfall, used the term spirituality, which she roughly described as ‘the experience of appreciating magnificent, unknowable powers at work in the world beyond ourselves’. I believe Franz de Waal has used the term, in a different context, for bonobos too, but I’m not so comfortable with the term, it’s way too vague, and it drags religion behind it too emphatically. A feeling of awe, or wonder, of being overwhelmed, etc, can be described as just that.
Jacinta: And yet. A noisy, crushing, powerful waterfall, a raging, dangerous, painful fire – attributing something like intention to these things seems like a step forward. And also the desire for mastery of these forces, by somehow understanding and manipulating their intentions, that might seem an advance. But it’s hard to tell, with our smug hindsight.
Canto: And talking about hindsight, many of us consider, from the pinnacles of science, that religion is just a hangover from the days of pre-scientific explanations. Why are we here? Because the god called God created us to have dominion over the birds and bees and beasts of the field, and after a female was built from a male rib (which must’ve contained some pretty impressive pluripotent cells), and after some snakey female behaviour, we were sent forth out of Eden to multiply, and the god left us to our own devices, but when he came back from wheeling and dealing in foreign parts, he found we were wrecking everything – female trouble again, doubtless. And so he decided to drown us all, so as to Make his Arcadia Great Again, but, presumably feeling a bit tired of the creation process, he chose a human family and unspecified number of species to float about in a boat for a while, watching their friends and neighbours drowning, so as to begin it all again, but definitely for the last time, because, having discovered golf, he’d really lost interest.
Jacinta: Yes, that’s one variant, perhaps not the orthodox one, but as Mary Midgley used to say, these sorts of stories provide a far richer account of our origins than anything scientism has to offer. I mean, life from non-life in a warm puddle? Boring.
Canto: But seriously, these creation stories, and ancilllary stories of the fruitful, deadly forests and the deserts and their oases, and the wind and the rain and storms and fevers and the patterned, watching stars and the smiling, burning sun, and the cool steadfast moon, these were as rich and comprehensive as they could possibly be, and those who remembered and told these stories best, and had the most intimate relations with all these insidious, ineluctable forces, would be precious persons indeed.
Jacinta: Mmmm. It’s a beginning.
References
https://www.theatlantic.com/science/archive/2016/03/chimpanzee-spirituality/475731/
how did life begin? part 1 – Greenland rocks, warm little ponds and unpromising gunk
the basics of the Miller-Urey experiment: sparking interest
Jacinta: Well, we need an antidote to all that theological hocus-pocus, so how about a bit of fundamental science for dummies?
Canto: Sounds great, I just happened to read today that there are three great questions, or areas of exploration for fundamental science. The origin of the universe – and its composition, including weird black holes, dark matter and dark energy – that’s one. The others are the origin of life and the origin of consciousness. Take your pick.
Jacinta: I’ll choose life thanks.
Canto: Not a bad choice for a nihilist. So life has inhabited this planet for about three and a half billion years, or maybe more, while the planet was still cooling from its formation…
Jacinta: Isn’t it still doing that?
Canto: Well, yes of course. An interesting study conducted a few years ago found that around 54% of the heat welling up from within the earth is radiogenic, meaning that it results from radioactive decay of elements like radium and thorium. The rest is primordial heat from the time of the planet’s coalescing into a big ball of matter.
Jacinta: Gravity sucks.
Canto: Energetically so.
Jacinta: You say three and a half billion years or more – can you be a bit more specific? Are we able to home in on the where and the when of life’s origin on this planet?
Canto: Well, that would be the pot of gold, to locate the place and time of the first homeostatic replicators, to wind back history to actually witness that emergence, but I suspect there would be nothing to actually see, at least not on the time-scale of a human life. I think it’d be like the emergence of human language, only slower. You’d have to compress time somehow to witness it.
Jacinta: Fair enough, or maybe not, it seems to me that the distinction between the animate and the inanimate would be pretty clear-cut, but anyway presumably scientists have a time-frame on this emergence. What allows them to date it back to a specific time?
Canto: Well, it’s an ongoing process of honing the techniques and discovering more bits of evidence, a bit like what has happened with defining the age of our universe. For example, you’ve heard of stromatolites?
Jacinta: Yes, those funny black piles that stick out of the water and sand, somewhere in Western Australia? They’re made from really old fossilised cyanobacteria, right?
Canto: Well, that’s a start, they’re rather more complicated than that and we’re still learning about them and still discovering new deposits, all around the world, both on the shoreline and inland. But the Shark Bay stromatolites in WA were the first to be identified, and that was only in 1956. More recently though, there’s been an entirely different discovery in Greenland that’s raised a lot of excitement and controversy…
Jacinta: But hang on, these stromatolites, they say they’re really old, like more than 3 billion years, but how do they know that? As Bill Bryson would say.
Canto: Well, good question Jass, in fact it’s highly relevant to this Greenland discovery so let me talk about radiometric dating, using this example. Greenland has been attracting attention since the sixties as a potential mineral and mining resource, so the Danish Geological Survey was having a look-see around the region of Nuuk, the capital, in the south-west of the island. The principal geologist found ten successive layers of rock in the area, using standard stratigraphic techniques that you can find online, though they’re not always easy to apply, as strata are rarely neatly horizontal, what with crustal movements, fault-lines and rockfalls and erosion and such. Anyway, it was his educated guess that the bottom of these layers was extremely old, so he sent a sample to Oxford, to an expert in radiometric dating there. This was in about 1970.
Isua rocks, Greenland. Oldest rocks discovered, showing plausible traces of 3.8 billion-year-old life
Jacinta: And doesn’t it have to do with radioactive isotopes and half-lives and such?
Canto: Absolutely. Take uranium 238, which if you’ve been watching the excellent recent ABC documentary you’ll know that it decays through a whole chain of, from memory, twelve nuclides before stabilising as an isotope of lead. That decay has a half-life of 4.5 billion years – longer than the life of this planet, or at least the life of its crust. So it’s a matter of measuring the ratio of isotopes, to see how much of the natural uranium has decayed. In this case, the gneiss, the piece of bottom-strata rock that was analysed, had the highest proportion of lead in it of any naturally occurring rock ever discovered.
Jacinta: So that means it’s likely the oldest rock? Aw, I thought Australia had the oldest. This is terrible news.
Canto: No time to be parochial when the meaning of life is at stake. May I continue? So this was an exciting discovery, but more was to come, and it’s continuing to come. The geological team were inspired to continue their explorations around the Godthaab Fjord in Greenland, and found what are called ‘mud volcanoes’, pillows of basaltic volcanic lava that had issued out into the seawater. These were again dated at about 3.7 billion years old, and this strongly suggested the existence of warm oceans at that time, with hydrothermal vents such as those recently discovered to be teeming with life…
Jacinta: Right, so that might be pushing the age of life back a few hundred million years, if it can be verified, but it still doesn’t answer the how question..
Canto: Oh, nowhere near it, but I’ve just started mate. May I continue? Not surprisingly this region is now seen as a treasure trove for those hunting out the first life forms and trying to work out how life began. It was soon found that the Isua greenstone to the north of Nuuk contains carbon with a scientifically exciting isotopic ratio. The level of carbon 13 was unexpectedly low. This is generally an indication of the presence of organic material. Photosynthesising organisms prefer the lighter carbon 12 isotope, which they capture from atmospheric or oceanic carbon dioxide. But the finding’s controversial. Many are skeptical because this is the period known as the ‘late heavy bombardment’, with asteroids crashing and smashing and vaporising and possibly even sterilising… and they haven’t discovered any fossils.
Jacinta: So, photosynthesis, that’s what created the great oxygenation, which created an atmosphere for complex oxygen-dependent organisms, is that right?
Canto: Well, that was much later, and it’s a vastly complex story with quite a few gaps in it, so maybe we’ll save it for future conversations…
Jacinta: Okay, fine, but couldn’t one of those asteroids have brought life here, or proto-life, or the last essential ingredient…?
Canto: Yes, yes, maybe, but you’re distracting me. May I please continue? Where was I? Okay, so let’s look at the various theories put forward about the origin of life – and it will bring us back to Greenland. You’ve mentioned one, called panspermia. That’s the idea that life was seeded here from space, maybe during the heavy bombardment…
Jacinta: Which isn’t an adequate explanation at all, because where did that life come from? I want to know how any life-form anywhere can spring from the inanimate.
Canto: Yes all right, don’t we all smarty-pants? One of the most interesting early speculators on the subject was one Charles Darwin, who wrote – very famously – in a letter to his good mate Joseph Hooker in 1871, and I quote:
It is often said that all the conditions for the first production of a living organism are now present, which could ever have been present.— But if (& oh what a big if) we could conceive in some warm little pond with all sorts of ammonia & phosphoric salts,—light, heat, electricity &c present, that a protein compound was chemically formed, ready to undergo still more complex changes, at the present day such matter wd be instantly devoured, or absorbed, which would not have been the case before living creatures were formed.
Now this was pretty damn good speculation for the time, and a couple of generations later two biologists, Aleksandr Oparin of Russia and John Haldane of England, independently developed a hypothesis that built on Darwin’s ideas.
Jacinta: Oh yes, they had this idea that if you added a bit of lightning to the early terrestrial atmosphere, which was full of ammonia or something, you’d get a lot of organic chemistry happening.
Canto: Well I think the ‘or something’ part is true there – their idea was that there was a lot of hydrogen, methane and water vapour in the early atmosphere, and that, combined with local heat caused perhaps by lightning, or volcanic activity or some sort of concentrated solar radiation, the combo created a soup of organic compounds, out of which somehow over time emerged a primordial replicator.
Jacinta: So far, so vague.
Canto: Okay, I’m just getting started. The Oparin-Haldane hypothesis was highly speculative, of course. The point being made was that this key event was all that was needed for natural selection to kick in. This replication must have been advantageous, and of course over time there would’ve been mutations,with the mutants competing with the originals, and the winners would’ve been the most efficient and effective harvesters of resources, and there would’ve been expansion and more mutations and modifications and so forth. And out of that would come the first self-sustaining homeostatic environment, the proto-cell, within which more sophisticated machinery for processing resources could be developed…
Jacinta: Okay so you’ve more or less succeeded in dissolving the boundary between the animate and the inanimate before my eyes, but it’s still pretty vague on the details.
Canto: In 1953, Stanley Miller took up the challenge of his supervisor, famous Nobel Prize-winning biologist Harold Urey, who noted that nobody had tested the Oparin-Haldane hypothesis experimentally. Miller created a mini-atmosphere in a bottle, using methane (CH4), hydrogen, water vapour and ammonia (NH3), and after sparking it up for a while, he managed, to the amazement of all, to produce amino acids, the building blocks of proteins. Surely the first step in producing life itself.
Jacinta: Ah yes, that was a famous experiment, but didn’t it turn out to be something of a dead end?
Canto: Well, yes and no. It has been replicated with different mixtures and ratios of gases, and amino acids, sugars and even traces of nucleic acids have been generated, but nothing that could be described as a primordial replicator. But of course this work has got a lot of biologists thinking.
Jacinta: But this was 60 years ago. That’s a lot of thought without much action.
Canto: Well, what has since been realised about the experiments of Miller and others is that they create an enormous complexity of organic molecules in a rather uncontrolled way, a kind of chemical gunk similar to what might be created when you burn the dinner. The point being that when you burn the dinner – which is something necessarily organic like a dead chook, or pig, or tragically finless shark or whatnot…
Jacinta: Or a pumpkin, or Nan’s rhubarb pie..
Canto: Yeah, okay – you get this messy complexity, all mixed with oil and vinegary acids and shite – you get this break-down into gunk, and that’s easy. What’s hard is to go in the other direction, to build up from gunk into a fully fledged chicken, or a handsomely finned shark. And that’s what these experiments were trying to do, in their small way. They were creating this primordial-soup-gunk and hoping, with a bit of experimental help, to spark life into it, and basically getting nowhere. The problem is essentially to do with randomness and order. How do we get order out of random complexity? It’s easy to go the other way, for example with explosions and machine guns and such. We see that everywhere. But building the kind of replicating order that you find even in mycoplasma, the smallest genus of bacteria, from scratch, and by chance – well, that’s mind-bogglingly improbable.
mycoplasma, one of the simplest life forms – but try making one from scratch
Jacinta: So we have to think in terms of intermediate stages.
Canto: Yes, well, there are big problems with that, too… But let’s give it a rest for now. Next time, we’ll discuss the RNA world that most biologists are convinced preceded and helped create the DNA world we live in.
N B – This piece owes much to many, but mainly to Life on the edge: the coming of age of quantum biology, by Jim Al-Khalili & Johnjoe McFadden