Why Did Life Begin On Earth? [4K] | Origin | Spark

there's a way to make an entrance my destiny it was now a conspiracy of witches download vili today [Music] [Music] thank you [Music] astronomers estimate that the diameter of the observable universe exceeds 90 billion light years that's more than 500 billion trillion miles from one edge of the cosmos to the other the universe contains at least 170 billion galaxies with stars and planets so numerous they outnumber the grains of sand on all the beaches of the world [Music] nestled within this Cosmic ocean a sphere of water and rock is home to more than 8 million species of living organisms foreign this reality has inspired endless speculation countless theories and one very intriguing question [Music] what were the odds that life once emerged on the third planet from a sun orbiting within a spiral arm of the Milky Way galaxy where we just incredibly lucky or was there more involved than blind chance and random interactions of matter and energy [Music] [Music] as the human inhabitants of Earth it is easy to take life for granted in fact we're spoiled by its abundance [Music] our climate and geography support a biosphere that may be unique in the universe and there's almost no location that's too hot too cold or too isolated for living organisms to flourish amid this spectacular diversity perhaps the greatest challenge ever faced by science Echoes from every insect Redwood and whale [Music] how did the first life Arise at a moment in time when there was no life of any kind how did life on earth begin [Music] where do we start I mean there are dozens of theories and you find you've got this wild diversity of viewpoints many of which are mutually contradictory try to crack the mystery you have to supply assumptions about what must have happened in the distant past there's no direct evidence because no one was there to witness the event and there's virtually no fossil record what we never observe ever is non-living chemicals forming a cell so in a sense we have a field of research where the important action has already happened [Music] the primordial history of Earth is indeed an incomplete narrative yet despite an absence of physical evidence most scientists believe that life started when energy sparked non-living matter in the planet's oceans crust and atmosphere to create building blocks for the first self-replicating cell when you come to the origin of Life the rules and this isn't the science itself this is the underlying philosophy the rules say to solve the problem you can use matter and energy and natural law natural regularities and chance processes but that exhausts your toolkit what you're not allowed to use fundamentally by the rules so-called rules of science is mind or intelligence if you had to attach a name to this position you can't do better than scientific materialism a philosophy that tells you the only acceptable explanation has to be rendered in terms of matter and energy and if you can't solve the problem using those tools you're not allowed to change the rules so from that perspective how did Life come to be via matter and energy alone now try to solve the problem [Music] all life that has ever existed on Earth is composed of cells and clues to their origin are woven throughout a network of molecular machines enclosed within a modern eukaryotic cell complex biological mechanisms carry out their work while suspended in liquid each of these machines is lifeless but together they Empower growth movement metabolism and reproduction the vital functions of life every component in the cellular Factory is made of large compound molecules and the most numerous are proteins functionally diverse proteins are engineered to unwind and copy genetic information in a strand of DNA trigger chemical reactions with their hand and glove shapes thank you control the passage of electrolytes and nutrients through the cell membrane [Music] and toe containers filled with cargo over scaffolds also made of proteins that auto assemble and extend to wherever they are needed in the cell magnified 500 000 times a red blood cell contains 280 million hemoglobin proteins each designed to carry oxygen by isolating one of them we discover that every protein is built from hundreds of smaller molecules called amino acids 20 different types of amino acids are found in living organisms the distinct chemical structure of each molecule allows the formation of more than a hundred thousand different types of proteins construction begins when select amino acids are organized into a chain it's a process often compared to arranging alphabet letters into meaningful words and sentences individual building blocks are sequenced correctly the chain folds into a protein fully equipped to perform its tasks within the cell [Music] but if the amino acids are arranged in the wrong order the chain won't fold and is eventually destroyed the simplest living cell contains at least 300 different types of proteins and the biological Machinery necessary to grow reproduce convert energy store and process genetic information and protect its contents from the outside world similar components and functions were also required in the first living cell now let's apply this basic chemistry to a familiar theory for the origin of life [Music] scientists have long speculated about primordial oceans loaded with amino acids that floated around like bumper cars perhaps some of these random collisions produced a chain long enough to fold into a protein [Music] later more amino acids linked it to more chains that folded into even more proteins simultaneously other complex molecules including nucleic acids fats and sugars also assemble themselves into essential components then without four-sider Direction just the right combination of molecules somehow came together in this chemical soup to form a membrane that encased all of the specific machines required for a self-replicating cell [Music] and there you have it life from non-living matter foreign you know it all sounds so reasonable the problem is on the early Earth the internal complexity required to survive at all would be overwhelming because life as we actually know it is characterized by molecular machines and lots of them and if you take away that essential Hardware the cell ceases to be because there comes a point when you can't get any simpler and still exist below that means death one sometimes here's the criticism you can't take modern cell biology and project it into the past because whatever the first cell was like it was a lot simpler than what we see today all right I can entertain that as a premise describe the first cell if you're going to be the first living cell you need a boundary a membrane that protects you from the rest of the environment this membrane must selectively allow the passage of specific nutrients and raw materials required for fuel and energy foreign store huge quantities of genetic information in coiled strands of DNA tailed instructions for life are copied with remarkable precision then in factories called ribosomes this information is converted into chains of amino acids and proteins finally you'll be equipped with everything you need to reproduce future generations of cells these basic functions are performed by all living things there in a sense diagnostic of what it means to be alive so whether you were a cell in the past very simple cell or a more complicated cell today really doesn't matter you're going to have to perform these functions despite daunting obstacles the notion that basic chemicals once arrange themselves into a living cell has been suggested for at least 150 years in 1871 Charles Darwin wrote a letter where he described a warm Little Pond filled with all the right chemicals to create life [Music] half a century later the Russian biochemist Alexander o'parin expanded Darwin's ideas in his book the origin of life he theorized a primordial soup and a gradual progression from simple chemistry to a living cell then in 1952 this hypothesis was put to the test [Music] Stanley Miller a graduate student at the University of Chicago set out to determine if simple chemistry could produce actual building blocks of life the young scientist constructed a glass apparatus to simulate the ancient water cycle and filled it with a mixture of gases that were thought to comprise the atmosphere of the Primitive Earth Miller heated the components then charged the gases with bolts of lightning electric Sparks to trigger a reaction within days a Tarlac sludge formed in the glassware in it Miller identified four of the 20 amino acids found in proteins for the first time under presumed natural conditions molecules crucial to life were generated from matter and energy [Music] there was tremendous excitement when the Miller experiment was first published because it looked as if it was easy to get the building blocks of living things and if it was easy to get the building blocks maybe it wasn't so hard to get from those chemicals to the first living cells while groundbreaking in its premise Stanley Miller's experiment later proved to be deeply flawed because he hadn't used the correct gases neglecting nitrogen carbon dioxide and oxygen that would have destroyed molecules required for life on the early Earth but despite these errors Miller's work inspired more attempts to recreate Prebiotic conditions today after Decades of Investigation hope for a swift clear pathway to a solution has long faded yet origin of Life research continues throughout the world its core hypothesis that living cells emerged from natural chemistry is now known as chemical evolution chemical Evolution comes with a lot of baggage and if you're going to take it seriously as an explanation for the origin of life then you also need to take seriously certain fundamental properties of biology the molecules involved in life they have no intelligence they have no foresight they have no way of knowing what they need to do next in order to get themselves assembled into organic chemistry if I put amino acids in a test tube in my lab even if I added heat and shook it up real well and kept doing that for a hundred years or a thousand years or ten thousand years or a million years nothing would happen amino acids nucleotides lipids by themselves they do not represent life they're inert they're not reproducing they're not storing information in a sense they're dumb they didn't wake up one morning and say hey let's all get together and build a cell that can replicate itself didn't happen Chemistry by itself is indifferent to whether anything is alive or dead natural selection won't work to make the first cell because natural selection can't work on anything unless it's got some means of inheriting and monitoring change and and then choosing the best Survivor to go forward to have selection at all you need cells so if you're trying to explain the origin of cells you can't use selection because selection requires the existence of the very thing you're trying to explain natural selection has to work on a cell that has a genetic system and is capable of reproducing without that already present natural selection is irrelevant Health Organization is the idea that chemicals can organize themselves in some way that turns them into purposeful information Rich objects molecules and atoms can self-organize in one sense salt would be an example in the salt you have sodium and you have chloride ions and they interact with each other because they have positive and negative charges so that natural Affinity leads to the assembly of sodium chloride sodium chloride sodium chloride which then can pack together in a stereotypical way to make a crystal salt crystals are the same thing repeated over and over and over again if a salt crystal was a book it would be a book of one word regular repeating geometries like that do not carry the right sort of information information that you would need let's say to build a protein the sequence that we see in a protein is highly irregular there's no way to predict what the next amino acid would be given the ones you've seen already so the self-organization that we actually observe in the natural world is the wrong kind of process to build you the information-rich structures of living things so once you eliminate natural selection and self-organization and you realize that molecules have no ability to think or plan ahead in any way chance rears its ugly head and scientists hate chances and explanation for the origin of life [Music] so why is Chance such an unsatisfying option perhaps because many analysts have done the math and understand the formidable odds against success is defined as the unknown and unpredictable element in any event that has no assignable cause or guidance from a natural law or intelligent agent since the 17th century one tool has been used consistently to predict the outcome of such events it is called mathematical probability in very broad Strokes here's how the theory works when you flip a coin and call heads the probability of being correct is 50 percent or one chance out of two flip two coins and the odds of getting two heads simultaneously are one chance and four three coins and three hits on a single try one chance and eight every time an additional coin is added the probability of success in this case all heads on the same toss is reduced exponentially by a multiple of two so if ten coins are tossed the probability of 10 heads is one and two to the tenth power or less than one chance in a thousand foreign to the origin of life and the random formation of large biomolecules probability Theory clarifies the limitations of chance as a creative agent on the primordial Earth for example what are the odds a single protein could form exclusively through the blind interactions of chemistry our Target is one smaller than average molecule made from 150 amino acids each aligned to ensure a folded chain researchers have calculated that on the ancient Earth the probability of success was one chance in 10 to the 164th power that's one correctly sequenced protein chain for every 100 million trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion failed attempts but despite these enormous odds some theorists argue that given enough time Anything is Possible okay let's test the validity of this opinion we'll Begin by establishing an ideal environment for chemical evolution an imaginary world that will provide chance with every opportunity to succeed first we stock the oceans to capacity with amino acids that means all the atoms on Earth including its entire supply of carbon nitrogen oxygen hydrogen and sulfur are available to form 10 to the 41st complete sets of the 20 types of amino acids used to build proteins [Music] then we'll alter the laws of nature to protect these building blocks from the destructive rays of ultraviolet light and chemical contamination in the primordial soup now let's turn the chemistry loose and see what happens [Music] the amino acids start bonding furiously in our experiment an entire chain of 150 units self-assembles in only one second since all 20 types of amino acids are available at the majority of sites there is a five percent or one in 20 chance the correct molecule will align in the chain if the sequencing is incorrect the chain is immediately destroyed and a new assembly begins throughout the planet six thousand million billion trillion trillion attempts will take place every minute foreign that means in 4.6 billion years the oldest estimated age of the Earth the number of chains that don't fold will exceed 10 to the 58th power it's a staggering total but nowhere near 10 to the 164th the trials necessary on average to build a protein of 150 amino acids by chance so if undirected chemistry can't produce our coveted molecule during the entire history of the Earth then how much time would have been needed to find out let's take a road trip we'll start by erecting a bridge that spans the diameter of the observable universe a distance of more than 90 billion light years then we'll place an amoeba on one end of the bridge foreign this single-celled organism will travel at the Breakneck speed of one foot per year [Music] it's off while we wait for one protein to form by Chance the amoeba slides along for more than 5 billion billion billion years to cross the entire universe and then return but this race is just getting started the amoeba takes off again successfully reaches the far side of the cosmos then heads back home [Music] yet not even one functional protein is anywhere in sight for the next trip we'll add a payload a single atom [Music] after inching its way another 500 billion trillion miles the amoeba drops off its cargo and returns for more [Music] will it get back before our lucky protein forms absolutely in fact it will complete another 10 round trips then 20. a hundred a thousand and there's still no sign of a usable molecule [Music] the amoeba continues making round trips until it is hauled off every atom on Earth then all of the atoms in our solar system then every planet and star in the Milky Way galaxy one atom at a time in fact as we wait for one protein to self-assemble the amoeba has so much time that moving at just one foot a year and carrying one atom per round trip it will transport the entire universe more than 56 million times that's how long it would take for chance to build one functional protein now suppose Against All Odds chemical Evolution produced our single functional protein would we have life no we'd have one protein just a lifeless arrangement of amino acids the simplest living cell we know has more than 300 different proteins but proteins are only part of the story when you consider any actual cell remember you're going to have carbohydrates complex sugars nucleic acids DNA and RNA lipids a whole variety of different chemicals which jointly constitute the living State those bits and pieces all have to be brought into the same microenvironment at the same moment in time each chemical building block must then be assembled and organized into the network of molecular machines that will control every facet of life if we can appreciate exactly how hard it is to produce one molecular machine using nothing except atoms and energy we can see that there's a profound problem because once you have one molecular machine you don't have a living thing these molecular machines need other molecular machines and even if nature was capable of producing all the molecular machines necessary that still wouldn't be enough they have to all be together all in this tiny little membrane-bound space that we call a cell from my understanding of what it takes to make a cell it has to happen all at once you can't do it one bit at a time because everything works together in a causal Loop the higher level of organization transcends the pieces the spatial organization in the cell requires that molecules end up in the right place at the right time the DNA is copied into RNA the polymerase that does the copying has to find the right spot in the DNA to start copying the RNA has to somehow hook up with ribosomes which have to be in a particular place and the proteins then that are made have to be going to a particular place that's an awful lot to account for by random chance the probability that you would get them in the same space at the same time becomes Beyond unimaginable and the probability that you would get them within a membrane enclosure like a cell is the next best thing to Impossible with chance completely out of luck the search for a viable materialistic explanation has branched in several directions [Music] theories include clay Services etched with cracks where organic molecules could be attracted and aligned into chains of nucleic and amino acids hydrothermal vents on the sea floor that spewed chemical building blocks from underwater cauldrons heated hundreds of degrees [Music] and primordial oceans filled with RNA a versatile molecule able to both store and replicate genetic information theoretically without the assistance of DNA or proteins proposals like these have sparked considerable interest yet each faces the same obstacle that destroyed chance the transformation of lifeless components into the complex biomolecules of life this problem is evident in the RNA World hypothesis RNA world is this idea that you can string together enough nucleotides to make a chain long enough to copy itself and then once copied to do the same thing over again origin of Life researchers imagine the very first life as being made of nothing but RNA and that it could somehow bootstrap its way to a bigger world where there's protein and DNA nobody's got an idea how that would happen since the introduction of RNA World Acceptance of the theory has increased despite numerous limitations including the molecule's durability if you just look at an RNA molecule it seems to Fall to Pieces working with RNA is extraordinarily difficult because it's so delicate it's meant to be a temporary store of information and as a consequence of its delicacy it's extraordinarily unlikely that it's going to be useful as some kind of starting point for life so RNA can't precede the first cell because it has to be enclosed in a cellular environment to be stable to be copied to be useful today RNA molecules are manufactured under laboratory conditions for many biochemists these synthetic strands of nucleic acids are at least partial confirmation that chemical Evolution once ignited life on the primordial Earth if you want to build RNA in the lab you have to spray down your surfaces and wipe your pipettes and wear special gloves and keep it covered and then hope that you don't get any contamination because if you do the RNA is gone and then you have the sequencing problem to solve so you need scientists working hard to sequence the RNA and try different combinations and find one that might copy itself so you have to have a complicated string of RNA that can function both as The Inheritance and the enzyme in the system and it's the best Minds in the world working on it and they haven't succeeded in cracking the problem reflecting on the origin of life and the implications of synthetic RNA chemist Robert Shapiro noted the flaw with this kind of research is not the chemistry the flaw is in the logic that the experimental control in a modern laboratory could have been available on the early Earth in reality the odds against RNA forming on its own are astronomical building RNA in a lab requires a great deal of intelligence forethought careful planning and execution so getting the right sequence without mindfulness without intention isn't going to happen the probability of chemical evolution is further weakened by the composition of the primordial soup If there really was a primordial soup then chemically it would have been an absolute mess there are all kinds of competing cross reactions that would have occurred on the early Earth interfering with the chemistry that you want that means molecules that are not used by living things and actually are harmful to living things the conditions on the early Earth are hostile to life they are hostile to the formation of the kinds of bonds that are necessary to make biological molecules and that's where a huge problem developed because water breaks the bonds that hold together proteins water breaks the bonds that hold together nucleic acids like DNA water breaks the bonds that hold together polysaccharides like starch and cellulose so the origin of life could not have occurred in water [Music] faced with insurmountable challenges on Earth some scientists have expanded the boundaries of their search [Music] in 1976 Nobel prize winning biologist Francis Crick Advanced a radical alternative for the origin of life Crick suggested that our planet was seated with microscopic organisms transported from another part of the universe by an alien civilization this theory is called panspermia five years later physicist Frederick Hoyle offered a modified version of panspermia when he theorized that strands of DNA were manufactured by an intelligence in a distant Galaxy and then set adrift like dandelion seeds on a windy day some of this genetic material reached the Earth [Music] another version of the theory popularized by the Mars Rock a meteorite discovered in Antarctica contends that microbes evolved somewhere else in the galaxy and hitchhike to Earth attached to comets and asteroids in some ways you could argue that panspermia is really an abandonment of science because it places the problem Beyond real examination if science tells us that life probably didn't come into existence all by itself here on Earth then it must have come from somewhere else even if it sounds like a bad 1950s horror movie it came from outer space if I have difficulties forming life on planet Earth be because let's say the atmosphere required is geologically implausible or I can't get sufficient amounts of biologically relevant molecules those problems are going to exist on any other planet where we postulate that life arose we can't make them go away by moving the venue you know to another part of the Galaxy bottom line panspermia doesn't solve the problem of the origin of life it just moves it to another locality [Music] the shortcomings of panspermia have led some researchers to a theory that extends far beyond conventional astronomy the Multiverse according to this hypothesis ours is not the only universe instead billions or trillions of universes were once generated by some unknown natural process and as opportunities increased exponentially impossible odds became probable until inevitably over time just the right combination of raw materials environment laws of nature and a large dose of luck produce the molecules and biological machines required for the first living cell in other words within a vast theoretical ocean of universes someone had to win the cosmic Lottery and it was us often when I'm reading the origin of life literature considering some proposal for the formation let's say of RNA or proteins and even the author admits it's chemically implausible and I asked myself how did he get himself into this Jam invoking an implausible pathway for something that for all the world looks designed well he got himself into this Jam because a philosophy told him that's the only acceptable answer and at that impasse I want to say to the author look you know it's implausible I know it's implausible the reason that you ended up here standing at the edge of this Cliff staring at implausibility is because way back down the road you decided that only a materialist explanation would work how many different explanations that fail within the materialistic box do we have to have before we decide maybe we need to move outside of that box maybe we need another kind of explanation [Music] when one surveys the various theories of science theories of physics theories of chemistry theories of star formation these are theories about the world out there but when we come to the origin of life we're talking about a theory that involves us ultimately where we came from our ultimate Origins Our World Views our philosophies our science they're all interconnected and that separates the question of the origin of life from every other question in science natural science is not divorced from everything else that we know or believe about the world so a very narrow apparently technical question like how did RNA first come to be can end up connecting through the fabric of reality to a very different question like might there be a god is God possible is God possibly real if life in its full richness did not come to be via a strictly physical or natural process we ought to have indicators of that and I think the origin of life is the central Pivot Point on which a great deal ends up turning so I come at nature as a curious human being and I say what do I regard as the normal everyday indicators of intelligence do I see them in life and the answer is yes in abundance [Music] what we see in biological systems is a Marvel it's beautiful it's elegant and the more we learn about biology the more obvious design becomes when I first started out in intelligent design there were people posting things on the internet saying I I graduated from MIT and went on to University of Washington then did a postdoc at Harvard so they were saying things like well she used to be smart what happened [Music] actually materialism puts blinders on science and we miss what's most significant about the world so it's a very exciting time to be a scientist because we have this opportunity to look at things with new eyes with fresh Vision intelligence is extraordinarily helpful if we're looking for an explanatory framework for the origin of life that actually works with what we observe in nature nature looks designed life looks designed design intelligence explains things like all of the information that we find inside a cell [Music] there's nothing magical about living things I'm a scientist I don't really believe in magic I believe in mechanisms and causes that are sufficient to achieve the phenomena that I observe intelligence is sufficient intelligence is necessary therefore intelligence is the conclusion that I come to thank you [Music]

Channel: Spark

Views: 97,656

Keywords: Spark, Science, Technology, Engineering, Learning, How To, education, documentary, factual, mind blown, construction, building, full documentary, space documentary, bbc documentary, Science documentary

Id: 2w_gm67wh5Q

Length: 45min 20sec (2720 seconds)

Published: Fri Jan 27 2023