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Paleoanthropology Series Part 1 - TAS 208
1.3k Plays1 year ago
We talk a lot about human origins, so we thought this would be a good time time to do an overview of paleoanthropology, and the human evolutionary tree. In this first episode of the series we start with some of the oldest human ancestors including Sahelanthropus tchadensis and Ardipithecus ramidus.
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Transcript
Introduction and Episode Overview
00:00:01
Speaker
You're listening to the Archaeology Podcast Network. You're listening to The Archaeology Show. TAS goes behind the headlines to bring you the real stories about archaeology and the history around us. Welcome to the podcast. Hello and welcome to The Archaeology Show, episode 208. On today's show, we begin a series on paleoanthropology and human origins. Let's dig a little deeper, but stop when you hit rocks because that's people.
00:00:34
Speaker
All right, welcome to the show, everybody. Rachel, how's it going? Hello, pretty good. So we're down here, still hanging out in Mexico. Still here, yeah. We just love it here so much. And I'm actually looking at the Sia Cortez right now, like out the window of the RV. As you're recording. It's not a bad life. It's really not. No. Yeah. No, it's neat.
00:00:53
Speaker
Yeah, and we've got some good friends around us because we've re-situated as some people left the event that we were on and we've moved closer to the beach and it's just really cool. Yeah, it's just we're in this perfect situation right now where I'm like, I don't ever want to leave, but also this is not my country, so I'll have to go eventually.
Driving in Mexico: Observations and Experiences
00:01:11
Speaker
Yeah. Hey, and that just reminds me, you know, we've had to do some driving around here and I got to tell you what, the only real jerk drivers in this country are Americans. Every time somebody passes us on like a double yellow or just does something that's really like not cool, Arizona license plate every time. Or pretends the speed is in miles per hour, not kilometers. Right. Yeah.
00:01:33
Speaker
And by the way, I'm not calling out all Arizonans. It's just that that's the closest, you know, United States border. But it's all Arizonans. Yeah. All the ones that come down here anyway. Oh, my gosh. Yeah. They're just when you go to another country, it's beneficial to, you know, to you and to everybody to just respect their roles and the people. Yeah. And like, honestly, the consequences of breaking the rules here.
00:01:54
Speaker
Like that's not good for anybody. I don't know why people are so, I don't know. I don't know why they speed and don't stop at stop signs and don't follow the rules. But anyway, that's a different rant for a different day.
Introduction to Paleoanthropology Series
00:02:04
Speaker
Yeah, indeed. So anyway, we're going to talk about something and this is going to be a series we're going to do. We're not quite sure how many parts it's going to be because it's a big topic.
00:02:14
Speaker
Yeah. It like keeps growing and growing. So it might go from it's two for sure right now, but it might go to three or maybe even four. I think it's at least three or four. Okay. Yeah. So what we're talking about is paleoanthropology. And this is a podcast that I want to actually have on the archeology podcast network, but I'm not qualified to run it. Yeah. You know, I just have an interest in paleoanthropology and I'd really love it if a paleoanthropologist that happens to be listening that wants to have their own show will provide you the platform. You just bring the content and let's talk about this stuff.
00:02:44
Speaker
Yeah, because what we're going to do today is like a basic overview, kind of like what you get in paleoanthropology 101 in college. Which I don't think is a class that exists. I don't know. I took a class like that in college, but it's an overview because we don't have time to really deep dive every single one of these.
00:03:02
Speaker
We talk about this from
What is Paleoanthropology?
00:03:04
Speaker
a recent Discovery standpoint enough on this podcast that we thought it would be good to just have a well-researched deep dive episode into just what the whole timeline of human ancestors and human origins is. So that's what our goal is here. But overview though, not super into it.
00:03:25
Speaker
Exactly. Yeah. So discussing the term real quick, paleoanthropology, it's basically the study of fossilized humans and human ancestors and the stuff they left behind. Yeah. Yeah. That's basically all it is. I mean, it means old human. That's what paleoanthropology means. Yeah. So the study of old humans. And it's like they're fossilized for sure. So these are rocks. So they're like
00:03:47
Speaker
chipping rocks out of rock in order to find these things, which makes it very difficult. And it means that the preservation conditions need to be exactly right. And I think the paleoanthropologists these days have gotten really good at knowing where to look, where they might find the right kind of stuff, you know, the right kind of
00:04:06
Speaker
preservation to find things, but it's still really hard to find. It's like that one in a million find is going to be the thing that like fills in a hole on the tree of humans and human origins. Which is the first thing I want to talk about. Yes, let's talk about that. The human evolutionary tree is not a tree at all, it's a bush. Yes, very true. There are lots of parts to it. We live kind of in the only time in the human ancestral history where there's only one species of humans alive.
00:04:34
Speaker
Yeah, that's a good point. One hominid species. Yeah. Right? And that's it. These are all overlapping by like millions of years. So, yeah. There were sometimes, I mean, potentially even, you know, six, seven, eight, nine different species of hominid like creatures roaming the planet. Yeah, true. At the same time.
00:04:51
Speaker
I would say one caveat to that is that this is our eyes looking backwards at what we have found. So we're assigning all these different species to things based on the fragments that we're finding in the fossil record. And so we could be wrong. We could definitely be wrong about how many there were, what they date to and stuff like that. Well, we definitely don't have a complete picture.
Do Humans Evolve from Modern Primates?
00:05:15
Speaker
Yeah, it's a puzzle for sure.
00:05:17
Speaker
And that's the next thing I was going to talk about. Like, how do we know that we're talking about paleoanthropology and not primatology? You know, when you see something that's seven million years old and you're like, well, how do I put this on the human family tree and not on the, say, you know, chimpanzee or a gorilla family tree or something like that? And one of the reasons is because
00:05:36
Speaker
Well, first off, chimpanzees, gorillas, those types of things, they also evolve like every species does, but they haven't evolved in the way that the human line has, right? Chimpanzees are still walking on all fours. They've been doing that for 20 million years or more, and their common ancestor with us did. We'll talk about that in a minute. But what makes it something that we end up putting it as far as an ancestral line to current humans is was there some sort of
00:06:04
Speaker
evolutionary adaptation or some sort of change that we can note within this fossil that was found, that is a trait that humans have today or that led to something that humans have today, like upright walking, an opposable thumb, other kinds of things like your legs starting to shape so you can stand upright more often. Chimpanzees and gorillas and stuff can stand upright, but not for very long and it looks uncomfortable.
00:06:28
Speaker
the shape of the face is another one, whether the front part of it protrudes more like a monkey or it's flatter like a human. So those sorts of things are what they're looking at. And of course it always means finding the right piece of the fossilized skeleton in order to even assess that kind of stuff too. It's a hard business.
00:06:47
Speaker
I know we can have finger bones of unidentified hominid species right now that maybe we think are something else or sitting in the I don't know box, right? But it could be a completely different species of hominid. Yeah, without the rest of it though, it's hard to say and you have it out of context too. You're never going to be able to place it with the rest of that species. You just can't.
00:07:06
Speaker
The other thing we have to talk about in this segment, of course, is the, you know, the, the image that actually all anthropologists even love. I even love it. I love it too. You have to love it. It's the image of something like a monkey and then there's usually like eight or so steps and it turns out to be a human. Yeah. Some of my favorites are it then like, like hunches down and is that a computer or something like that or, you know, whatever goes on to like Bigfoot or Sasquatch or something. These ones are always funny too.
00:07:33
Speaker
But while we do appreciate that image and we like it, it's not accurate. Because humans definitively, and there's no debate or question about this, did not evolve from monkeys, chimpanzees. Chimpanzees aren't monkeys, by the way. Get that straight. Monkeys have tails, chimpanzees do not. And we didn't evolve from any of the current primate species that are alive today. But we have a common ancestor with all the primate species that are alive
Genetic Similarities with Primates
00:08:00
Speaker
today.
00:08:00
Speaker
We have a common ancestor that goes back, I think the last I heard was about 20 million years is the thought just from genetic. Really? Does it go back that far? Yeah, just from looking at the genetic code of the two species. There's a relatively well-known book by John Marks who's been interviewed on this show called Being 98% Chimpanzee.
00:08:19
Speaker
Just 98% chimpanzee, I think it's called. Oh, is it? Yeah, yeah. 90% chimpanzee. Great book. Because he mentions that we are, of course, we share 98% of the genome with the chimpanzee. That 2% makes us very different. But that's all it takes, right? Because the human genome and the chimpanzee genome are massive. Millions and millions of pieces of code here. And it only takes 2% of that to make us that much different. Because when it comes right down to it,
00:08:45
Speaker
We're both mammals. We both have hair. We just have less of it. We both reproduce the same way. We both have brains. We both have hands and fingers and toes. Yeah, even use hands the same way. There's a lot of similarities. It's just those little bit of changes in the genetic code make our brains a little bigger.
00:09:02
Speaker
make them structured a little bit differently and change our anatomy a bit. And that changes everything. Yeah, for sure. And just going back to the common ancestor idea, in case that's a phrase that it's super obvious when you learn about it, but it's not totally obvious when you first hear it. What does that mean exactly? But what we're talking about is an ancestor that
00:09:23
Speaker
is shared with another species. In this case, we're talking about chimpanzee or probably bonobo would be the closest one to humans, I think. But what happens is we share this point way, way far ago, 20 million years or whatever it is. And then from there, we branch off in two different directions.
00:09:39
Speaker
So rather than this linear thing where it's like this unbroken line bound to chimpanzees, it's this point where we break. And then, you know, in the one direction goes human and it's this crazy bush, like we talked about, like spreading in a bunch of different directions. And in the other totally different direction goes to chimpanzee line with all of their ancestors, which are completely different to what they are today as well. So that's the thing to keep in mind here. It's not linear. It's this branching
00:10:08
Speaker
Bush idea. And if you go back far enough, everything has a common ancestor with everything else. Sure. Because one of the things I always remember from that book from Dr. Marks is that we're also something like 74% daffodil. Because if you go back far enough,
00:10:26
Speaker
all living animals have a common ancestor with all living plants. Because we all go back to single-celled organisms. So when you go back to single-celled organisms, all multi-celled organisms have a common ancestor with single-celled organisms. And then those multi-cellular organisms started to change. They became fish eventually. I mean, they became a lot of amoeba and stuff like that in between.
00:10:47
Speaker
But then that started branching out and all you had to do was be successful in breeding. That's the only requirement for having your line continue. So if you had a genetic mutation or adaptation that was advantageous and by advantageous meant you could have sex because it doesn't mean you're even able to survive in your environment better.
How Do Genetic Traits Affect Human Evolution?
00:11:05
Speaker
It just means you're able to survive in your environment long enough to have sex and reproduce. That's literally all this means. It's true.
00:11:11
Speaker
Yeah, I mean, sometimes they even call it sexual evolution because it's that's the only thing you need to be able to do. Yeah. Right. And that's why your genes get carried along. And and that's why some have argued that our evolution has probably stopped because we're able to.
00:11:27
Speaker
not select out people that may have been selected out in the past. Like maybe somebody is born with a mutation or born with some sort of genetic disorder that would have made them unfavorable to be around for whatever reason. And then they wouldn't have been mated with and then they would have died without children. But now it doesn't really matter what you have. You can find a partner.
00:11:46
Speaker
And then you can have sex with that partner and if you can have kids Well, whatever you were born with that made you the way you are is now part of the genome It's getting passed on for good or for bad really interesting point and it's like the beauty of humanity in one way because you can be whoever you are and find a place that accepts you and be happy and have a lovely life but from a genetic standpoint and
00:12:09
Speaker
I suppose, yeah, everything is always being carried down, so nothing's being selected for, not really. There's probably small examples, and genetic drift is when you have a smaller population with various things going on genetically. That's a very bad explanation, but that's very, very simple, but yeah.
00:12:27
Speaker
And here's the other thing about the
The Complexity of Human Evolution
00:12:30
Speaker
human family tree. We're just going to keep calling it the family tree because that's what people call it. If you want to look up clades and like cladism, that's really what it is. Clades are just, it's almost like a diagonal line with little things coming off of it. That's really what the tree is these days. That's how geneticists talk about it. Either way, it's not really a tree. It's more of a bush. There isn't one single branching. And the reason for that is I was always taught that
00:12:53
Speaker
Things that were different species couldn't breed. They could have sex that's different than breeding. They couldn't breed and have viable offspring. It's like, um, I think the donkey or the mule, I always get them mixed up, but one of those can't actually breed. You can cross a horse and a donkey, I think, and get a mule.
00:13:09
Speaker
I think that's how that works. Yeah. But that mule can't reproduce it sterile. Right. But that doesn't mean that some of these branches of proto humans are hominids. We call them these things that are barely human. They're barely, you know, primate like they're, there's something in between. Some of them could breed. Yeah.
00:13:27
Speaker
and have viable offspring. And that way, you can have this one line and line one and line two breed and have viable offspring, and then line two and line three breed, because they all live at the same time, and have a viable offspring. And then now lines five and six, which are part of those, are now breeding and having viable offspring, or four and five, or whatever the numbers are. But you know what I mean? The kids are now breeding.
00:13:48
Speaker
not realistically, but maybe. And they're now having viable offspring. So because of that, you can have multiple species living at the same time with their own genetic mutations and differences, and then coming together and producing these crazy things that could also breed and then have their own. And then pass on that genetics down to the next generation, basically. And as the world changes, some things may become more favorable. Like, for example, they call
00:14:16
Speaker
the, uh, they call it the, oh, what do they call it? The, the aquatic ape theory, which is basically, you know, animals coming down from the trees, uh, like chimpanzees still largely live in trees. But as the Savannah encroached on Africa and the jungle like atmosphere kind of went away, they had to start coming out of the trees a little bit in order to hunt. And that way, you know, bipedalism, things that could walk upright and maybe throw something were a little more advantageous because they could live longer, have more kids.
00:14:45
Speaker
And then the whole aquatic ape thing is maybe they started spending a lot more time in and near water sources to get those animals. And that's why they maybe lost some of their hair and became more slick and hairless than their ancestors. I don't really know a whole lot about that. But either way, there's a lot of different theories on why certain mutations happened. And not why they happened, they happened because of random mutations, but why they were favored enough to propagate.
00:15:12
Speaker
Most would agree that it's because maybe you have some weird mutation, but maybe you only have one child. But if you're a male, to be honest with you, and you impregnate many females, and you have many children, whatever trait you have is moving on.
00:15:30
Speaker
If you're strong and you're seen as somebody who the women want to mate with, the females of the species, the females can only have so many kids, but the males can have sex with as many women as they want. And so it was often the male traits that were passed on that way because they could propagate a lot faster and a lot more than the females could. That's just biology.
00:15:50
Speaker
Anyway, we're going to spend the rest of this series basically talking about a number of examples and it's not an exhaustive list. It's not a thorough search. It's just some of the things that have contributed to the hominid family tree that were found and that were important and that we just want to talk about.
00:16:07
Speaker
Yeah, we're gonna kind of start from the oldest and then move to the youngest and sort of fill in the tree from there just to give an idea, an overview of who contributed to the genetics that we have today, possibly, possibly contributed their genetics.
Structure of the Paleoanthropology Series
00:16:26
Speaker
Like, you know, some of these might've died out without ever adding to modern, what became modern humans, but they have,
00:16:34
Speaker
Modern human they have characteristics that you see in modern humans or or the beginnings of them So yeah, yeah, there's some really cool cool ones to talk about here
00:16:44
Speaker
All right. Well, since we're not experts on this, we're going to take a break. And on the other side, we're going to talk to Chad and see what he thinks back in a minute.
Who is Sahelanthropus Tchadensis?
00:16:50
Speaker
Welcome back to the archeology show episode two oh eight. And we're talking paleoanthropology, oldest human ancestors. Yeah. And yeah, now we're going to go to Chad, which is in west central Africa. And we're going to talk about sah, hellenthropus chadensis.
00:17:06
Speaker
Yeah. So one of the first and most important physical characteristics that, that puts a species in the human line is the ability to walk upright bipedalism. Right. So Sakhalinthropus chadensis lived approximately 7 million to 6 million years ago. And they definitely show some of those characteristics.
00:17:29
Speaker
Yeah, and I think this one was discovered when I was in college, or at least published, because I remember it being a big deal and people talking about it. I do. I remember that as well. Same thing. Yeah, that would have been the early 2000s. Yeah, and we only have cranial bones so far for this species, but this is how they determine or they think that this species walked upright is that
00:17:50
Speaker
In the cranium, the position of the foramen magnum is further forward than it is in apes. Now the foramen magnum is where your spinal column comes in and joins with your skull. That's where the head bone connects to the backbone. Yeah, exactly. And all of the nerves and everything going into and out of the brain are kind of going through that area.
00:18:10
Speaker
So it's a really important part. And if you can imagine on a human, it's further back and that allows the head to sit upright more. It's what you would see in a species that is walking upright, right? Whereas in apes, it's forward and it's more in what you would see in a species that is not upright. It's on their hands and feet or even swinging in the trees or whatever.
00:18:33
Speaker
Yeah. And they need their heads right there because they're, they walk on all fours. Yeah. Mostly they, their head has to be further forward and they need that. But for bipedalism, which just means walking on two legs most of the time, you have to be able to look out in front of you. You don't want your head way out there. You don't want to, you know,
00:18:50
Speaker
You don't want to be looking down towards the ground either. You're up and facing forward. So that's one really good indication of whether a species walks upright. So I thought that was really interesting because you usually think of walking upright as looking at the pelvis or at the leg bones to get an idea of whether or not they're upright. But the position of the frame and magnum is another great way to look and make an assumption or a guess as to how they walk.
00:19:15
Speaker
Right. The cool thing about this is it's not it's not a human. Yeah. No, it's not hominid. It still has characteristics and ape like features as well. Yeah. And some of the ape like features where it's a smaller brain and even a little bit smaller than a chimpanzees for that matter. And this would have probably been a shorter creature as well. Yeah, definitely. Yeah. It had a sloping face, prominent brow ridges and then an elongated skull, you know, and probably like prognathic they call it where your face like sticks out a
Introduction to Orrorin Tugenensis
00:19:44
Speaker
little
00:19:44
Speaker
bit. Like you imagine a chimpanzee or any other sort of ape species. But it also had other human-like features, which included small canine teeth, short middle part of the face, and the frame and magnum, as you mentioned. So that's really cool. And these crossover species, of course, is what you see all the way up until Homo sapiens, sapiens, we call it, right?
00:20:04
Speaker
Almost all of them are a mix of human and ape. They have to be, otherwise they'd be human. Yeah, exactly. So it's very interesting to see what parts are human-like and what are more ape-like or whatever. So the next one dates to, the fossils we have date to somewhere between 6.2 and 5.8 million years ago. So kind of overlapping with the sahelanthropist chadensis a little bit too. This is the aurorin tugenensis.
00:20:30
Speaker
Yeah, and this was found in Eastern Africa, the Tuggan Hills. That's where that comes from. Most of these are named for sometimes a person and sometimes the place where they're found. And it's just, yeah. So either way, Tuggan Hills of central Kenya, and you're going to find that a lot of stuff was found in East Africa. Yeah.
00:20:47
Speaker
We'll probably get into that later, but there's a lot of reasons why things were found in East Africa. It has to do with the geology and the way things are exposed. Either way, this was found in East Africa, and this one was small, approximately the size of a chimpanzee. Again, most of these early species were coming from that smaller primate line.
00:21:06
Speaker
You know, once they started walking upright and getting bigger brains, they started getting physically taller and bigger, but it took millions of years for that to happen. Yeah. Right. I mean, we still have small humans. I knew somebody who was, you know, four feet, 11 inches tall. Totally. Right. And it's another thing to keep in mind, like.
00:21:23
Speaker
Yes, there are large primates. Gorillas are very big. Orangutans can get really big. But they're not in the same line. We have a common ancestor with them, obviously, but it's way, way further back. Apes, chimpanzees, and bonobos. Those are our closest ancestors, and they're much smaller primates. So you can imagine that anybody in our human evolution line, our pre-human evolution line, is gonna be much smaller. And these guys definitely were.
00:21:50
Speaker
Yeah, some of their other human-like characteristics were small teeth and thick enamel. So for this species, we have a femur that shows evidence of the bone buildup on a femur that is typical of bipeds. And honestly, that's really all we need, right? We may not have more of this that we've identified as definitely belonging to this species, unless you find it in association with other bones. It's really difficult to tell that.
00:22:13
Speaker
So we may have more examples of the species, but they may be called something else, or they may be called nothing at all, or they may be called the wrong thing. You need those perfect pieces to tell you what species you're looking at, or if it's something that is in the pre-human evolutionary line.
00:22:29
Speaker
But while you think everybody looks different that's sitting around you right now, or people you see on the street, people you go to work with, we all have a lot of the same internal stuff that looks exactly the same. The only thing that would make a femur look really different between two identical humans standing next to each other is some sort of pathology, right? Some sort of disease or something they had that altered their femur. But when you get down to the bone level,
00:22:53
Speaker
you can really tell a species and even sometimes the sex depending on the bone and then sometimes the age depending on how the bone developed.
Identifying Early Human Species
00:23:02
Speaker
Those things, age and sex are usually something that you can tell pretty well from the bones, but yeah.
00:23:08
Speaker
And like there's been some really bad like pseudoscience that has happened over the years where people saying that they can tell what race somebody is. But but really like you can't. You just cannot because there might be certain characteristics that are more common in certain regions of the world than in other regions. But that is the closest you can get to saying that kind of thing.
00:23:27
Speaker
But that being said, because somebody probably heard of this, there have been really good AI facial reconstructions done of like skulls and things like that. And once you have the actual face, you can start to see features that may be regionally specific, you know, racial, if you will, but regionally specific.
00:23:44
Speaker
But it's really difficult to tell that just by looking at the bones. You really need a computer to put it all together and pull those little pieces together and say, yeah, your cheek looks like everybody else's, but in reality, it kind of looks like this a little bit. There's these things that you just can't tell until you build it up and you have that data set.
00:24:02
Speaker
That's why the features like the protruding face and stuff like that are really easy to distinguish between primates and humans because that's a very obvious difference. And when you get primates like these kind that we're talking about that have this sort of mix of human and ape characteristics, it looks kind of protruding like a chimpanzee, but maybe not quite as far and that kind of stuff. That's how you know you're looking at something that's in that line somewhere along the way, probably. Yeah.
00:24:31
Speaker
Yeah, and this one probably walked, but also climbed trees. They get a crossover species. Yeah, definitely. I mean, we climb trees now.
What are Ardipithecus Species?
00:24:38
Speaker
So climb trees better. I mean, we shakily climb trees, or at least I do. All the times that I try and climb trees. All right. Well, Chad didn't get us too far, so we're going to take a break and see what Artie can do with us on the other side of the break. Back in a minute.
00:24:54
Speaker
Welcome back to the archeology show. Two Oh eight is the episode number. And this is our first paleoanthropology series. Yeah. And we are talking about a few fossils and we're back. I mean, 4 million years plus. Yeah. And that's how far back we're going here. And there's, there is stuff that's been found that's much older, but we're talking about, you know, really specific things that show definable traits that led to what became modern humans.
00:25:21
Speaker
Yeah, and these are fossils and species that most of the paleoanthropology world agrees are at least somewhere in the human evolutionary tree. So there are others that are outliers, but these ones are pretty well established as being part of it.
00:25:38
Speaker
Right. And I mentioned arty at the beginning. It's only because when this genus was first announced, it was called Ardipithecus, right? And there's a number of fossils in the Ardipithecus line. Yeah. And the genus that makes it Ardipithecus, that's some of the more common traits. And then you add on the extra little bit and this generally gets down to where it was found.
00:25:57
Speaker
and maybe some slight differences in what we're talking about. So we're gonna talk about two from the Ardipithecus range right now, but yeah, they were nicknamed Artie early on, the first one that was found. The first one was Artie, yeah. Which we'll talk about in a minute. But the first one here that we're talking about now is Ardipithecus cadaaba.
00:26:13
Speaker
Yeah, and Ardipithecus cadauba was somewhere in the 5.8 to 5.2 million years ago range. And I don't think they have that many examples of it. So when we give a range like that, it's probably the best range that they could get from the dating. Whatever dating they were able to do on it, that's the range that's...
00:26:34
Speaker
And that's something we might include in this series, because you can't date fossils. No. But what you can date, and in 99% of the time, what they dated here was the volcanic deposits above and below it. And there's uranium-thoron dating. There's a number of others. Potassium argon dating. Potassium fluoride is what you brush your teeth with. Potassium argon dating.
00:26:55
Speaker
I should never say things without researching first. Where's Google? Right, potassium argon dating. And what that means is these are radioactive elements. And when they decay, they decay from one thing into the other. And when you measure the ratio of those chemicals within something, then you know basically how much time has passed because you know what the half-life is of that radioactive element. Right.
00:27:18
Speaker
So either way, that's how they date these things. And they usually have a layer up here and a layer down here, and you know it's somewhere in the middle. So when you say 5.2 to 5.8, there must have been a 5.2 million layer of volcanic material, and then a 5.8 million layer of volcanic material, usually basalt. These flows happen all over Eastern Africa, and that's why we have such
00:27:38
Speaker
Really such good dating on these things is because these volcanic flows happen all the time for millions of years Yeah, so anyway in the middle of Wash Valley in Ethiopia is just so to speak a wash with Hominid remains. Yes. So it definitely is I think we're gonna be talking about this area and yeah, you know in the next couple of episodes too Like there's just so much going on there and we have talked about it on other episodes like news episode, too They're they're always finding stuff here. So
00:28:02
Speaker
Yeah, so this one was similar in size to a chimpanzee. Again, we don't really get bigger than this until we start hitting around the two million year range. Yeah, definitely. But we only have a few post cranial bones, some teeth and a large toe bone in the fossil record for this one. Not a whole lot.
Challenges in Reconstructing Fossils
00:28:18
Speaker
No, but the toe bone is the important one here and the one that makes them think that it's part of the Ardipithecus species and that it would have been bipedal ish, probably a combination. And it's broad and robust and it could have been used for what they call the bipedal push off, which is exactly what you think. Like when you take a step with your foot and you're pushing forward with that front part of your foot and your toes, that's the bipedal push off.
00:28:45
Speaker
Yeah, and feel it. You can feel it if you just walk barefoot. Feel where your big toes are. You can feel that just kind of dig in and keep you upright. You need that strength and that feet and that shape in order to help you walk upright, basically. It's the one thing that robots can't seem to get right when you see them try to walk bipedally. Oh, they always walk heel first, don't they? Yeah. Well, they just can't do it. It's really hard to do.
00:29:09
Speaker
The canine teeth also resemble later hominins, which is pretty cool. But again, we don't have much about this species. So these are going to be pretty short conversations. Yeah, they are. There's not a whole lot else to say. But we know that it's from in that space within the two lava flows. So if somebody wanted to go looking for more of this, they at least can pinpoint what layer they might find them in. That doesn't guarantee you'll find anything. But you can at least pinpoint that. You know what you're looking for. Yeah.
00:29:34
Speaker
Now, the next one is Ardipithecus ramidus, and this is the first Ardipithecus species that was defined and dates to about 4.4 million years ago. Again, Eastern Africa in the middle of Wash region of Ethiopia and also in Gona in Ethiopia. So a couple of different places there.
00:29:51
Speaker
Yeah. And this one is the one that's nicknamed Artie. And I feel like this might have been discovered recently. Well, when we were in college, it was a more recent discovery because there was a lot of emphasis put on it. I just remember it being like one of the big ones that we covered in college.
00:30:06
Speaker
Anyway, it's a partial skeleton with foot bones and a crushed pelvis that they were able to reconstruct, right? And that's important because that's like that's a lot of pieces for a fossilized Skeleton to have foot bones pelvis and you know various other fragments to them
00:30:23
Speaker
And here's the thing, there could have been traits that were passed along that didn't necessarily make it into what we would call modern humans today, but also didn't make it into anything else. Yeah, they just died away. We're not saying that all of these traits that came about were ultimately successful, right? They weren't. And this is probably an example of that because the foot bones here have a divergent large toe
00:30:45
Speaker
with a rigid foot. And this isn't very human-like, but it's also not very chimpanzee-like or ape-like. And by divergent, they mean like the toe kind of like... Kind of like shot out. Yeah, like shot out away from the rest of the foot. So that wouldn't have made walking super easy, I would imagine, right?
00:31:01
Speaker
It could have made gripping trees very easy, though. So it's hard to say what this being would have done. And you might be thinking, well, maybe this was a deformity. Maybe this was a non-standard version of a member of the species. But the general theory in paleoanthropology is you're going to find the average representative sample of that species. Because there were millions of them alive. And if you found one of them, the chances of that one you finding being something that had some sort of genetic deformity,
00:31:29
Speaker
that none of the others had is so unlikely. So unlikely. The possibility is not zero, but it's so close to zero that it's almost not worth talking about. So it very well could be this, but we need more examples. So.
00:31:42
Speaker
So like I said, they were able to reconstruct the pelvis and from that reconstruction, they say that it has adaptations for both bipedalism and also tree climbing. So maybe doing a mix of both based on the shape of the pelvis that they reconstructed.
00:31:59
Speaker
However, there's always a however, right? There is criticism of the conclusions that are drawn from the reconstructed crushed pelvis. Yeah. Which makes sense. I mean, like it's a crushed pelvis, a crushed fossilized four million year old pelvis. Right.
00:32:18
Speaker
that a bunch of modern human scientists looked at and said, this piece goes here. I mean, they might have done it perfectly correctly, but there definitely is some room for error there. And also like you're interpreting something based on crushed pieces and you don't know when that crushing happened. And I don't know, there's just, there's just a lot of room for error there. So I can see being skeptical of whether or not
00:32:44
Speaker
These adaptations are actually truly for bipedalism or even tree climbing. Who knows?
00:32:50
Speaker
Yeah, but it does have some other human like features like the canines again. Sounds like canine teeth evolved pretty early on to be similar to what we have today or became what we have today. Yeah, for sure. If you look at them in a picture, you can see that human canines tend to be smaller and more diamond shaped than than ape or primate ones. Well, just imagine a chimpanzee with like smiling. They have like fangs almost. Yeah.
00:33:14
Speaker
Yeah, I mean they're they're pretty stout canines we used for like ripping flesh Yeah, but you need that when flesh isn't cooked right these guys were cooking stuff back then but we're starting to get to the point where You know you you could eat different foods based on you know what you were doing So anyway, this is about all we're gonna talk about today, but we're gonna continue this series and
00:33:37
Speaker
bring you a lot more paleoanthropology.
Episode Closing and Contact Information
00:33:39
Speaker
There's so much more to discuss. And once we start getting down into some of the really nitty gritty here, it gets really fun. And then I can talk about my experiences digging two million year old fossil bed layers in Africa. Yeah, for sure. Yeah. So all right. Well, with that, we will see you guys next week with some more paleoanthropology. Bye.
00:34:05
Speaker
Thanks for listening to The Archaeology Show. Feel free to comment and view the show notes on the website at www.arcpodnet.com. Find us on Facebook, Instagram, and Twitter at arcpodnet. Music for this show is called, I Wish You Would Look, from the band C Hero. Again, thanks for listening and have an awesome day.
00:34:29
Speaker
This episode was produced by Chris Webster from his RV traveling the United States, Tristan Boyle in Scotland, Dig Tech LLC, Culturo Media, and the Archaeology Podcast Network, and was edited by Chris Webster. This has been a presentation of the Archaeology Podcast Network. Visit us on the web for show notes and other podcasts at www.archapodnet.com. Contact us at chris at archaeologypodcastnetwork.com.