Transcription
[Music] we'll be doing now this introduction to what is abiogenesis and how does that differ from evolution because many people don't know they're confused on this so so let's go through that.
well the reasons for this lecture just before we get started this lecture series on a biogenesis let me just touch on this dave farina posted a a video entitled elucidating the agenda of james tour a defense of abiogenesis you can see in the description blog box below for the link after watching that video i was confused about almost every slide and statement that dave farina presented it really was there were numerous gross scientific inaccuracies not just inaccuracies not just little things big big things in his claims in my opinion it's my opinion since others might likewise be confused i'll use the farina video with time stamps is the launch point for the series of lectures so you'll see a little number like it might say 10.23 that means at 10 minutes and 23 seconds that's where that quote came from uh and then look i'm thankful for dave farina and his attempts to teach the layperson about scientific topics on his youtube channel professor dave explained so there's a plug for for your youtube channel that's a commendable endeavor i therefore seek no contest with dave farina only clarity i got nothing against him and i think it's it's it's wonderful to teach scientific topics to the masses this is an important thing to be able to do and this is something that that is admirable all right other synthetic chemists can comment and point out where i am correct or incorrect i particularly invite a critique from my synthetic chemist colleagues and students studying synthetic chemistry and those studying origin of life if disputing please reference a literature article so that i can read and learn just want to read and learn so if you'd cite that as you're critiquing that would be helpful all right let's get into this.
abiogenesis abiogenesis is the origin of life from non-living matter and this is from merriam-webster online dictionary abiogenesis is the origin of life from non-living matter to construct any convincing theory of abiogenesis we must take into account the condition of the earth about 4 billion years ago i'm still quoting so so we have to use chemical techniques that might have been available on a prebiotic earth nobody was here there was no biology yet so this is before biology this is the chemistry that was needed to assemble life for a synthesis to be categorized as being prebiotically relevant it must use chemical reagents and conditions that are presumed to be available upon an early earth or accessible to an early earth it is not what we can do today now first of all we've never made life today we've never made a single cell we have not uh that's something that maybe i'll address in this and i'm sure i'll address that in this nobody's ever made a cell people have modified cells people have brought new materials into cells but nobody's ever made a cell abenicio from the bottom up uh but but uh uh we have to use reagents that were accessible on an early earth abiogenesis takes place before biology and before biological evolution can begin so before evolution can begin before that first cell can can can change into morph into other other cells and and start start reproducing uh it has to form how did that first formation happen that is before biology hence it's prebiotic or pre-biology that's the difference evolution is taking something that has life and and transforming it this is before you ever had life that's what a biogenesis is all right.
what are the characteristics of life uh again quoting this is not my this these are these are uh uh published definitions quote responsiveness to the environment growth and change ability to reproduce have a metabolism and breathe maintain homeostasis being made of cells and passing traits onto offspring now homeostasis is a steady internal physical and chemical condition our cells are are highly in highly non-equilibrium states they have this internal steady condition or some people include cellular organization reproduction metabolism heredity response to stimuli growth and development and adaptation through evolution so some have even added adam to adaptation to evolution some origin of life researchers are trying very hard to redefine life to some very very basic level that doesn't include many of these things doesn't include a cell i've seen people say you know it's it's not much more than than a uh than a reaction that is auto catalytic and then if that's the case a nobel prize should be given to osvald or he should have gotten one for for uh origin of life to come up with with the first first uh reaction that was auto catalytic auto catalytic means that a reaction makes something and that's something that it's made becomes a catalyst for for the next structure to be made and so it becomes a template of sorts for another structure to be made and uh uh that's that's uh that's autocatalysis many reactions uh show this property of autocatalysis all right.
what are the conditions of the early earth nobody was here well there's speculation well there is this article published in december of 2011. so not that long ago here it was published in nature which is the top journal in top scientific journal and and here's the title of the paper and uh uh i'm quoting from from uh um the article and from the news report from the article that was written from the institution where the this this paper came out says for decades scientists believed that the atmosphere of early earth was highly reduced meaning that oxygen was greatly limited such such oxygen poor conditions would have resulted in an atmosphere filled with noxious methane carbon monoxide hydrogen sulfide and ammonia to date there remain widely health theories and stu and studies of how life on earth may have been built out of these deadly atmosphere cocktails out of this dead deadly atmosphere cocktail unquote as of 2011 however it was suggested that quote the earth just 500 million years after its creation was not a methane-filled wasteland as previously supposed but instead was much closer to the conditions of our current atmosphere so people used to think that or many people may still think that that the earth was highly reducing had had uh ammonia would and which is a highly reducing uh environment and and hydrogen sulfide and so so that that uh um there was very little oxygen around and then it's more recently that people are suggesting no that early earth was probably more like it is now closer to conditions now we don't know we don't know nobody knows for sure because nobody was there but i'll give you either you want a reducing earth you want an oxidizing earth we'll take either we do chemistry with either see how far we can get that that that doesn't inhibit me or my uh my arguments at all.
what were the conditions of early earth well whatever the conditions were it did not consist of a pristine laboratory there were no fine chemical producers where one could purchase the starting materials or reagents or buffers everything had to be made from very simple organic and inorganic compounds such as ammonia methane oxygen carbon dioxide hydrogen sulfide sulfate water formaldehyde carbonate formate cyanide possibly hydroxide etc all of these small comets that's all there was now i don't know any origin of life researcher that really starts out with just these sort of things maybe miller and yuri did but but very few people start from that point now there were no discernible sources of naturally occurring homochiral amino acids to polymerize into proteins no place to buy nucleotides nowhere to order homochiral sugars no stores that sell phospholipids no human-designed coupling agents or protecting groups no pristine glass vessels no purified solvents no degassing steps no vacuum pumps no ability to conveniently turn reactions on and off no simple method to transfer chemicals from one reaction vessel to another prebiotic earth had enormous barriers so when you say somebody can synthesize a compound today in a modern laboratory that doesn't mean anything we're talking about abiogenesis how were those compounds made on an early earth we have to restrict ourselves to those types of conditions if those reactions that we're doing are going to be what are called prebiotically relevant bringing the chemicals to earth from outer space only transfers the mystery had to happen somewhere so if it came from outer space well we just extend the chemistry to there what how did the chemist how did that happen we've got to somehow figure that out all right.
definition of prebiotic from this article on evolution education outreach this is what was written as published by james cleaves james cleves writes prebiotic chemistry can be understood to mean various things chemistry which occurred before life began or the chemistry which led to life on earth and possibly on other planets workers in the field practically define it as naturally occurring mainly organic chemistry in planetary or other solar system environments which may have contributed to the origin of life on earth or elsewhere the term abiotic chemistry chemistry which takes place in the absence of biology and prebiotic chemistry are in some senses synonymous since it is generally assumed that the universe is not goal directed and since it is not known what processes led to the origin of life the study of prebiotic chemistry almost certainly includes both productive and non-productive chemical processes what that means is that there's a lot of stuff that's synthesized that is just trash that doesn't move on in the direction that we want and those are impurities that are going to have to be addressed what are the four classes of macromolecules large molecules needed for life what are the building blocks of those macromolecules well polysaccharides are carbohydrates their building blocks are monomeric sugars and these encode information sugars are huge encoders of information on the way that they are assembled and so there's actually more information can be stored in sugars than in dna and rna and and so you have to have the the building blocks polysaccharides and the building blocks of the building blocks the monomeric sugars you have to have the proteins their building blocks are amino acids enzymes are generally catalysts for synthesis of biological molecules and they are large proteins these encode information nucleic acids like dna and rna their building blocks are a trimer of a nitrogenous base linked to a pentose 5-carbon sugar that's linked to a phosphate in this trimeric form it's called a nucleotide these encode information lipids their building blocks are fatty acids glycerol phosphate and often ethanol amine there are functional assemblies in code information many people don't realize that but that's what's being shown that these these you have domains of them and they will swarm they're not homogeneous these lipid bilayers and they swarm depending on the on where you are in the action of the cell and in the life of the cell all of these encode information there's information encoded in these molecules just like or in the in the lipid case in the organization of the lipids just like a bar code on a box encodes information just like the magnetic strip on your credit card in codes information or like the the silicon chip in your credit card encodes information all of these in code information we have to deal with the information encoded in these as well all right.
so there is a car got a lot of parts how many people could take all of those parts and assemble that car even with directions it'd be pretty hard what if you had no directions could you do it well maybe some people could if they're nicely laid out like this if they were all jumbled up it'd be much harder and you know this isn't even all the parts certainly there's some assembly already here done but this is just a lot of the parts now what if these weren't all nicely laid out for you what would you do it'd be much harder you had no directions what if you had no tools to put it together you know that had no shop to do this you had no vice you had no no vice grips you had no screwdriver i mean what would happen then even harder now what if instead of all in a nice room like that they were spread out throughout the earth some in in hydrothermal vents at the bottom of an ocean some next to a volcano some in other pools that dry and refill every day some in very cold environments some under the earth some in the himalayas and others at the bottom of the ocean and that's where you distributed these parts then what would you do you have to find the parts before you could get them back together that'd make it even harder well some people say well a lot of this came from outer space okay let's distribute the parts in outer space now all of those got to somehow come together so we can form that car that's very much like what you have to do with a cell you got to get all the parts and you got to get them together before they can start functioning those are the four basic classes of a cell remember this is not my definition it's life has got to have a cell if you want to redefine life separately go ahead and do that but we're talking about cellular life it's hard this is what you're up against in abiogenesis it is a hard problem now the other thing is parts decompose you know you leave a part out in the in in the desert or by an ocean these things are going to start decomposing plastic parts in the desert aren't going to last long metal parts in an ocean aren't going to last long do molecules decompose you bet they do and if you say well there was not an oxidizing environment like scientists are saying today on an early earth there was a reducing environment okay tell me what ammonia does to molecules tell me that that's a pretty strong reagent toward molecules tell me what uh hydrogen sulfide can do to molecules so there's always molecular degradation molecular degradation is happening all the time sure synthesis can be happening as well as degradation molecules don't last long we'll see lots of examples of that i will cite papers on that i won't just make claims i will cite papers for you here's the synthesis problem composited molecules that compose living systems almost always show homochirality they have one chirality we will have a whole a whole video on homochirality so i'll explain that to you when building molecular systems constant redesigns are needed which take the synthesis back to step one it's often impossible to remove a morty once it's been added to a molecule so if a synthesis is going along it doesn't know where it's going because the early earth is mindless and and it's going along it's gone on 100 million years and uh oh it's stuck on the wrong group how do you go back a lot of times you can't easily remove a group not all reactions are in equilibrium the same in the forward reaction is in the reverse reaction so so for someone to claim that they're all reversible with an equilibrium constant of one or something is that utterly ridiculous you can have an equilibrium constant easily of 10 to the 5th 10 to the 6th 10 to the 7th molecules don't always go back the the synthetic reactions do not know how to stop their current course of progression or why to stop there's no targeted goal in in abiogenesis time can actually be the enemy because molecules decompose over time and often quickly under conditions for their formation you'll see how chemists run reactions we'll look at the actual prebiotic chemistry that is coming out of groups where the yield goes up and after say 24 hours it's optimized and then the yield starts dropping down quite quickly so what does the chemist do he or she goes in and stops that reaction when it's optimized how do you tell a prebiotic earth to stop the reaction at that point because it doesn't even know what it's trying to make doesn't know what it's going toward if you don't fish the reagents out of a reaction they end up going to a mess a prebiotic system does not have the ability to easily purify structures if it doesn't have the ability to purify structures you've got to deal with all sorts of other products and those suck up the starting materials very hard to bring impure products highly impure where your product might be just one percent of what you want and bring that forward to the next step and have things going well very difficult to do that nobody knows how to deal with that problem a reagent addition order is essential when you're making a cake you put the icing on last you can't just throw the icing in with the milk and the eggs it doesn't work that way there is a precise order you got to have the same thing in chemistry when you're building complex molecules precise order is essential how that happens on an early earth you can speculate but you'd have to speculate that it happened over and over and over again and just so precisely so it didn't mess up the chemistry that you'd that had already been formed the parameters of temperature pressure solvent light or no light ph atmosphere gases or no gases have to be carefully controlled in order to build complex molecular structures you see the same thing in the procedures that are done by origin of life researchers themselves and you'll have to scratch your head and say how was that done on an early earth how did that ever happen over and over again once maybe maybe over and over again like that you say well i had a lot of time we'll have a lot of time to decompose as well as we'll see the characterization at each step is essential for the chemist but it's hard in a prebiotic system to consider because it knows nothing of molecular structure doesn't know how to how to to know if it's pure or not biology does biology has has has receptors that that can detect and if if these these molecules are not the right shape i mean there's other molecules that come and and and break them up i mean biology is amazing remember this is all pre-biology chemistry it's much harder to think about how that was done chemically the mass transfer problem would be the killer of all roots how do you start with a little bit of material and then and then and then carry that on many steps you say it happened you want to start with a kilogram of material how did that carry on you want to start with a ton of material how many how many steps can you get through especially when you don't even know where you're going you don't know how to optimize on each step how do you do that did it run the whole kilogram or the whole ton of material at once okay and then what happens if you have a one percent yield what happens if you have a one percent yield then then you drop down to to just 100 kilograms what happens if you have another one percent yield for the next reaction now you've gone from a ton to a kilogram what happens if you have another one percent yield now now you're you're down you're down to uh 10 grams i mean it's it's a problem it goes away very very quickly nature keeps no laboratory notebooks so it can't go back and bring through more starting material because it never knows never knows what it had done so even it gets to a certain point it doesn't know how to go back these are big problems these are big synthetic problems they're going to play origin of life research to think about this most of these have never been addressed by any origin of life researchers why not because they haven't thought about it it's because nobody knows it's hard to address these are smart folks that are working in the area of origin of life these are hard problems to address origin of life molecules don't care about life organisms care about life chemistry on the contrary is utterly indifferent to life without a biologically derived entity acting upon them like a human being molecules have never been shown to evolve toward life never they don't evolve toward life there's no impetus to evolve toward life molecules don't move toward life biology keeps caring about life organisms do cells do but not molecules never been known to to move toward life so this whole word of taking evolve and putting into the realm of synthetic chemistry is really a misnomer these these things don't try to go toward anything there's no impetus to go toward anything so with that we we conclude on this on on just giving you this basic background on on uh introduction of what is abiogenesis and so from here we'll just take it on to the next step and we'll talk about uh the primordial soup after this okay thanks for joining us thanks for joining us if you want to subscribe just click right here subscribe and we'll give you a shout out when the next video in this series comes out thank you.