Episode Transcript
[00:00:05] Speaker A: ID the Future, a podcast about evolution and intelligent Design.
[00:00:12] Speaker B: Welcome to ID the Future. I'm your host, Andrew McDermott. Well, today I'm joined by Dr. Casey Luskin to discuss an intriguing topic he's written on recently. A new study claiming the early and rapid rise of luca, our alleged last universal common ancestor. The study raises some tough questions for evolutionary theorists. Dr. Luskin, in case you don't know, this fine fellow is Associate Director and Senior Fellow of the Discovery Institute's center for Science and Culture. He is a scientist and attorney with graduate degrees in science and law, giving him expertise in both the scientific and legal dimensions of the debate over evolution. He holds a PhD in geology from the University of Johannesburg, where he specialized in paleomagnetism and the early plate tectonic history of South Africa. Casey, welcome.
[00:01:03] Speaker A: Great to be with you, Andrew.
[00:01:05] Speaker B: Well, today we're discussing a paper that came out in Nature, Ecology and Evolution earlier this year that discussed the last universal common ancestor, also known as luca. So what exactly is the last universal common ancestors are supposed to be? Is this a hypothetical organism or something we've actually established?
[00:01:25] Speaker A: Yeah, that's a really important question you're asking, Andrew. And it's important that we kind of set the stage here for. Are we talking about something real or something hypothetical? The last universal common ancestor, which is often called luca, is really a hypothetical organism, which is thought to be, as it says, the last universal common ancestor of all living organisms. And basically what they do is they look at the genes and the traits that are present in the major domains of life that are alive today. Basically, that would be bacteria, archaea, and eukarya. And they say, what are the common features of these genomes that are found throughout the entire tree of life, all the branches of the tree of life? And they say, okay, well, those traits, those genes, those genomic components must have been present in whatever was the last common ancestor that they had. The most recent common ancestor that lived for all of these, you know, supposedly lived for all these basic types of organisms must have had these traits in order to explain why these same traits are now found today among living organisms on these various branches of the tree of life. So it's an evolutionary concept. It's a hypothetical organism. You know, we're not saying this thing actually lived, although I think most evolutionary scientists would say they believe it lived. Of course, if you disagree with certain evolutionary presuppositions, you might question the existence of luca. We can get to that later. But it is not a real thing. It's a hypothetical organism. That represents sort of this common ancestor of all living organisms that was the most recent common ancestor that had all these traits that we find in common among the genomes of living members of all the branches of the tree of life.
[00:03:06] Speaker B: Okay, got it. Now, is this the same as talking about the simplest possible form of life that could exist? And if not, how is it different?
[00:03:15] Speaker A: Yeah, that's also a very good question. We're not necessarily talking about the first life form. What, you know, evolutionary biologists would say was the quote, unquote, simplest life form that ever lived. They would say that this is a life form that lived after the origin of life, but it was the ancestor. It's the basically the most recent ancestor, the most recent organism that lived that was the ancestor of all living organisms that are alive today. Okay. So if you were to trace back every single organism, were to trace back its ancestry, universal common ancestry, this organism would be in the family tree, the ancestral tree of every single one of the organisms that are alive today. Okay. And so it's not necessarily the first or most simple organism that ever lived. In fact, we'll get into this. But, you know, if we talk about the most simple cell that we know of that can live today, it's not simple at all. It actually has about 438 protein coding genes, 35 RNA coding genes, and over 500,000 base pairs in its genome. That's when we look at living organisms that are alive today, and we say, what organism has the quote, unquote, simplest genome? That is the simplest genome that we're aware of that gives you an organism that can live. So that actually is simpler than this last universal common ancestor that they have inferred from this paper that we're talking about today. However, that's not the simplest organism. The simplest organism would have lived before. That would have been more simple. And according to mainstream evolution, life would have then evolved complexity until it got to this last universal common ancestor, luca, which then branched off to all the organisms that we have today.
[00:04:53] Speaker B: Okay, now, when did the researchers in this study at least find that this last universal common ancestor supposedly lived?
[00:05:02] Speaker A: Well, they say that it lived over 4 billion years ago. Precisely, they say between 4.09 and 4.33 billion years ago. And again, this is all hypothetical. Okay? So don't think that, like, if you're willing to challenge certain evolutionary presuppositions, don't think that you have to accept these numbers. But what's interesting is this pushes the supposed timeline when life existed on Earth into the very, very early reaches of Earth's history. You see, according to mainstream science, Earth supposedly formed about 4.5 billion years ago. As a geologist, I don't have any problem with that date. But now we have life living perhaps as early as 4.3 billion years ago. What that means is that you don't have, you know, hundreds and hundreds and hundreds of millions of years or even billions of years for life to arise on Earth. We have life, according to this study, existing on Earth already in a very complex form within, say, you know, 200 or 300 million years after the Earth formed. That is not what most origin of life theorists want to hear. They want to hear that life first formed on Earth, say, a billion years after Earth formed, maybe 3.5 billion years ago. But according to this study, we are pushing the age of life back to 4.09 to 4.33 billion years ago. Now, it's important to note that this is not fossil evidence of the first life. The first fossil evidence that we have of life, sort of the hard evidence we have of fossilized bacteria, I would say, comes in around 3.7 to 3.8 billion years ago. Now, there are some studies that will say, because we have really large air bars on the ages of some of these rocks containing these early fossils, it may go back to, like, 4.2, 4.3 billion years ago, which would be consistent with what this study is finding. So it's not impossible that life, you know, according to the fossil record, lived this far back. But we're not talking about fossil evidence of life in this study. What they've used in this study is what is called molecular clock techniques. Okay, so, again, this is based upon looking at the different types of organisms that are alive today and sort of making this assumption that there have been sort of random mutations accumulating in the various lineages leading to these various types of organisms. And if you assume that these random mutations just accumulate at a constant rate, then you can infer back, okay, well, then when. How long ago did it take for all these mutations to basically accumulate in these types of organisms that we see alive today? And they infer that this was about, you know, basically 4.1 to 4.3 billion years is how long it would take for these organisms to accumulate all these mutations that we see in these various forms of life? And so it's a molecular clock technique, and there are many, many assumptions that go into molecular clock dating techniques. I personally am quite a big skeptic of molecular clock dating. Number one, not only does it assume that Universal common ancestry is true, a claim that I think is very dubious. And there are many reasons to doubt that, but it also assumes that organisms have been accumulating random mutations at a constant rate over time. And I think there are also many reasons to doubt that assumption as well. So. And there's many other assumptions that go into molecular dating techniques. But it basically, if we just, you know, for the sake of the argument right now, what we want to do is we want to say, look, this is sort of the most cutting edge evolutionary science here, and it is finding that life existed on Earth very, very early. And so if you are an evolutionary scientist, you don't want to hear that life basically arose so quickly on the early Earth. You want, there'd be lots of time for life to arise. And this study is sort of removing that time from the evolutionary timeline to allow for life to not just arise, but hit a very large level of complexity. We'll talk about that soon. You know, how complex was this universal common ancestor? Last universal common ancestor? And we'll see that it actually was quite complex.
[00:08:59] Speaker B: Yeah, yeah. And that was actually my next question was, I mean, this is, you know, this is supposed to be the luca, the last universal common ancestor, but it's really anything but simple. Tell us how complex it actually was.
[00:09:14] Speaker A: Yeah, exactly. Oh, go ahead. Sorry.
[00:09:16] Speaker B: Just allegedly, you know.
[00:09:17] Speaker A: Yeah, exactly, allegedly. Of course, really all of this is in the context of, you know, very subjunctive tense, allegedly. You know, if we make a bunch of assumptions, evolutionary assumptions. But again, if you want to take an evolutionary view, this is cutting edge evolutionary research. This is where you have to go. Okay, so according to this study, the last universal common ancestor had a genome that was about 2.5 megabases. That's 2.5 million base pairs in size. And it had at least 2,600 genes. Okay. About 2,500 protein coding genesis or 2,600 protein coding genes, depending on exactly who you ask. So we're looking at, you know, basically 2.5 million base pair genome, at least 2500 genes in this organism's genome. That is very, very complex. In fact, that's far more complex than the sort of minimal bacterial genome size that we're aware of today, which is about 531,000 base pairs encoding about 438 protein coding genes. So this is very complex. So clearly, this is not the first life. Life had to originate far earlier than this last universal common ancestor, which pushes the origin of life even further back. And you've got to have enough time to evolve from that first organism, whatever it was, to this last universal common ancestor with these 2.5 million base pairs and, you know, 2,500 protein coding genesis. And it's thought that it was capable of basically synthesizing the building blocks of life. This last universal common ancestor, luca, could synthesize nucleotides, it could synthesize proteins. It had a cellular envelope. It used ATP as its energy currency, much like life that is alive today. It had basic metabolic processes. It probably. It had a diet of hydrogen gas and carbon dioxide and even had a basically a what was called a rudimentary immune system for fighting off viral invaders. So this is not a simple. Of course, even, you know, the simplest known organism is not simple at all. It's probably more complicated than any technology that humans ever made. But this is far more complex than even the simplest known organism that we were just talking about. You know, with that 530,000 base pairs, 438 genes. This had 2.5 million base pairs in its genome, and it had about 2,500 genes. So it was not a simple organism. It was very complicated, and yet it lived within, say, you know, 200 to 400 million years of the origin of the Earth. Okay, so that's a lot of complexity arising very, very quickly. And I think that this has sort of caused some consternation for origin of life theorists. And I should also add that this organism had genes to protect itself against ultraviolet radiation damage. So there's a lot of complexity in this organism's genome, and that's a lot of complexity to evolve very quickly. In fact, there was a scientist who commented on this research in the Washington Post and talking about, you know, the early Earth being a very hostile place for life. Okay. There were lots of huge asteroid and meteorite impacts, bolide impacts that were constantly impacting the early Earth. And these are thought to probably be sterilizing early Earth. And so according to this scientist who combat that, he said that is a lot of evolution to happen within 100 million years or less. And I would say, yeah, that's exactly right. You're going from basically, you know, no life to life, which of course is not simple, but at least it was there to a very complex form of life, as complex as many living members of bacteria or archaea, basically, many prokaryotes that are alive today have genomes that are just as complex as this organism. And it happened in perhaps less than 100 million years, certainly no more than a couple hundred million years. So we're talking about basically A very, very rapid origin of life. And again, this is not what origin of life theorists want to hear. They want to hear simple life at the early stages of the Earth and lots of time for it to evolve. But this study is showing complex life at the early stages of the Earth history and not a lot of time for it to evolve. This is not good for evolution in the origin of life.
[00:13:40] Speaker B: Okay. And, you know, established media doesn't really make it easy for the educated layperson to learn about this or at least see the dimensions in the debate. You know, with headlines like meet the surprisingly complex ancestor of all life on Earth. You know, Washington Post, I mean, they just sort of toe the line. They just kind of take that and run with it. Is that helpful? I mean, how do, how does the everyday layperson tap into the nuance in this debate?
[00:14:14] Speaker A: Yeah, exactly, Andrew. It's not helpful. And this is something, of course, we've commented on many times here at Discovery Institute that when you just read the technical literature and sort of the mainstream, you know, media, it's not going to give you a full picture of what's going on. This article was published in the journal Nature Ecology and Evolution, and that was where this technical paper came out. So if you dig into that paper, you're going to appreciate just how complicated this organism was and how little time there is for the origin of life on Earth. When you read the mainstream media commentary, I think that you're not going to see people really acknowledging, oh, this actually could pose a problem for the origin of life. I think that this Washington Post story did thankfully acknowledge, hey, that's, that's very rapid evolution. But they're not saying this actually poses a problem. You know, you really have to, I think, look at the implications of this. And this is why we have ID the future and evolution news, to help people appreciate and understand what the implications of the science is really saying.
[00:15:10] Speaker B: Yeah, yeah. Such an important resource. EvolutionNews.org? well, can we trust the conclusions of this study? I mean, what were the methods? You've, you've mentioned it a little bit, but how did they come to their conclusions of the nature of this luca?
[00:15:26] Speaker A: Yeah, again, they used basically comparative genomics and molecular clock techniques to infer just how complicated was this last universal common ancestors genome. And again, what they did is they compared the genomes of living members of the basic domains of life, bacteria, archaea and eukarya, and they found what genomic components or genesis are in common among those three major domains of life. And then they said, okay, well, those had to then be in existence in this last universal common ancestor. Well, of course, this whole method assumes the universal common ancestry is true. It assumes that, you know, that there's no other way to explain why we have similar parts among the various domains of life other than inheritance from a common ancestor. But if we take an intelligent design perspective, then of course, it could be that the various domains of life share these similarities due to common design. The designer found it expedient to put these very useful and necessary genes that are necessary for living, you know, in a DNA based, protein based organism. You need these genes. And so that's why these various domains of life have these genes for, you know, metabolism, synthesizing the building blocks of life, a basic immune system, et cetera. That's why we see these genes so widespread. So, but then if you take an evolutionary perspective, you have to assume, oh, that means that the last universal common ancestor had to have had all these genes in common. So as a ID proponent, I would be skeptical of, you know, I don't have to necessarily accept the conclusions of the study that there had to have been a last universal common ancestor that was complex like this. Okay, fine. But I also want to ask the question, is an evolutionary story, you know, really making sense here? And from an evolutionary perspective, probably you should trust these conclusions because then you're going to accept universal common ancestry and you have to accept, you know, that these genes probably were in the last universal common ancestor. Otherwise you have them arising independently in different domains of life, which is very, very unlikely. And so if you accept these conclusions as an evolutionist, you then have to accept that, you know, what, life was very complicated very early in Earth's history. And that implies, you know, as the scientist said in the Washington Post, a lot of evolution happened very quickly. And I think that that kind of makes people feel a little bit squirmy and nervous. They don't want to hear that. They want to hear that you have loads of time for the origin of life to take place and studies like this are taking that away.
[00:17:50] Speaker B: Yeah, yeah. So the origin of life landscape is, you know, having some troubles as it is, as we've heard from Dr. James T. And Dr. Stephen Meyer. What does this imply for the origin of life on Earth in general?
[00:18:06] Speaker A: Yeah, it implies that the origin of life happened very quickly on Earth and also that life was very complex very quickly. And again, none of this is what you want if you're an origin of life theorist. You want lots of time for complexity to originate very slowly. But we don't have that. If you're an evolutionist, you've got to acknowledge that there was not a lot of time and the complexity built up very, very quickly. And so from an idea theorist perspective, this is exactly what we do expect.
Large amounts of information appearing in a very complex organism's genome very early in the history of life on Earth. And of course, we have a good explanation for where that information comes from because in our experience, information always comes from an intelligence, from a mind. So intelligent design does not have any problems whatsoever with lots of genetic information appearing very rapidly on the early Earth. It's when you're an evolutionist, I think, that you want to get lots of time to have for that happen very slowly, but that's just not what the evidence is showing. So ID theorists, although you might be skeptical of the evolutionary methods and assumptions used in this study, I think that we can still say, look, life was very complex very early in Earth history. And that's a conclusion that we could agree with.
[00:19:16] Speaker B: Yeah. Well, I'm sure glad you've covered this at Evolution News just to highlight this new study and the problems that it brings up for a Darwinian view of life. Now, Casey, where can listeners learn more about this topic?
[00:19:31] Speaker A: Yeah, they can go to evolutionnews.org where I wrote a couple articles about this paper in Nature, Ecology and Evolution. We have a link to that paper and also link to some news stories. So go to Evolution News and you can read all about it.
[00:19:43] Speaker B: All right, Casey, thanks for turning up here and talking about this. It's great.
[00:19:48] Speaker A: All right, well, it's the day before Thanksgiving. I'm going to go home, get some sleep, have some turkey tomorrow.
[00:19:52] Speaker B: Hey, good plan. I'm going to do that, too. Well, thank you for joining me, Casey, and listeners. It's always a pleasure to have you along for the Ride for ID the Future. I'm Andrew McDermott. Thanks for listening.
[00:20:04] Speaker A: Visit us at idthefuture.com and intelligentdesign.org this program is copyright Discovery Institute and recorded by its center for Science and Culture.
