3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia
bbc.co.uk
bbc.co.uk
This seems to be the rule, rather than the other exception, at least in human evolution. Erectus overlapped with more modern archaics, for example. Habilis overlapped with afarensis.
A lot of these are more about the semantics than the substance. Words like "species" get tricky, when you're dealing with chronspecies, introgression and such.
In any case, our evolution since speciating from chimps is extremely bushy. There are lots of species, and several families. The process involved lots of innovation/speciation and extinctions. Ie, The australopithecine family that this species may have founded produced many species, including at least two that formed their own families with multiple species of their own (paranthropous & homo).
I think this is characteristic of fast evolutionary processes.
"You could fit it all into the back of a pickup truck if you didn't mind how much you jumbled everything up." - Ian Tattersall
https://www.goodreads.com/quotes/6578939-since-the-dawn-of-t...
It also seems like every time they find a new fossil, they change their mind about how everything fits together. I am not an expert in this field, but if I had a small dataset and I fit a very complex model to it with literally hundreds of free parameters and I found that the model completely changed every time I added a few new data points and re-fit, then I would conclude I was dealing with a high-variance model that was overfitting the data and either use a simpler model or wait until I had collected much more data before trying to fit such a complex model.
So... keep digging!
I'm reading "The Greatest Show on Earth" (which is a fantastic book for a broad overview of the evidence for evolution. The evidence is truly astounding and awesome). Dawkins spends a bit of time arguing that the distinction between micro and macro isn't that meaningful. However, I just skimmed the Wikipedia pages and it seems the terms may have some legitimate usage? Perhaps his unfortunate dealings with creationists have simply spoiled the terms for him.
This species is now the oldest known australopithecine, by a hair. It is a contemporary and possible ancestor of afarensis. It's true that we don't know (and probably won't because it's too old for DNA) if these fossils just represent diversity in a species, subspecies or several species. We do know that they're similar to each other. We also know that they existed 4mya. Divergence from chimps is thought to have happened around 6-7mya (also controversial, and subject to change). So... all the australopithecines at that time were probably genetically compatible, considering apes slow breeding and how long it takes most large mammals to completely speciate.
Considering how different they are from chimps and similar they are to each other, it's a decent guess that they are closely related. We know that the genus had at least 5 types/subspecies/species, 6 if we include habilis.
Baboons occupy a similar niche to australopithecines. There are 5 closely related species. They hybridize often, but still maintain these separate species/types, probably because it's adaptive in their respective ecosystems. It's meaningful that australopithecines had a similar pattern.
An interesting side point is that there's some speculation that baboons emerged once australopithecines (inc habilis) declined, homo (erectus) emerged and the ecological niche became free.
So yes, we can't tell exactly which of these extremely closely related types represent distinct "species" and which of these is our immediate ancestor. But, that's more semantics than substance. We have pretty strong evidence that early homo was an australopithecine type, within a closely related (recently emerged) genus.. and that there was probably a lot of hybridization within the genus.
There's a lot to the difference between definitive knowledge and no knowledge.
We can see multiples things:
- Disregard the 2010, it is indeed up-to-date. These past few years new bars have been added regularly.
- A single homo species is a new development and is an exception and not the rule
- Not only did different species live at the same time they sometimes lived in the same places
- There is no edges between the groups to represent ancestors as a simple "single ancestor" link is not easy to establish.
[1] https://www.college-de-france.fr/media/jean-jacques-hublin/U...
Homo habilis started its career as an australapithicine, and could probably reproduce with "non-homo" species.
A lot of the classification only makes sense after the fact. If habilis hadn't produced the homo genus, it would just be an australapithicine, and we wouldn't consider it separate from them.
Horses & donkeys have a different number of chromosomes. They're also separated by an estimated 4m years of evolution, which is around the rule of thumb limit for large mammal hybridization so it makes sense that they're borderline hybridizable. They have shorter generations than us apes.
Anyway, mules are healthy. No survival issues. They are mostly infertile, but not 100% of the time.
It seems pretty clear that rather than various "species" and isolated lines that there is all sort of mingling of the lines and trees, and to some extent you can expect it happened in places that you otherwise might not have assumed before.
I love my boy Steve!
"There's a whole bunch of land, let's dig... [throws dart at map] here."
The fact that we can still derive meaningful knowledge out of that compounded fraction of fraction of a percent is amazing; and the quantity of mind blowing things that happened that we will never get to know because they weren't "recorded" is humbling.
The discoveries also make it seem like they just found a hominid skull, but in actuality they find hundreds of fossils (animals mostly, a few hominids) and it takes years to sort and identify the fossils. It always amazes me that the expert can take a small bone fragment and determine hominid vs deer vs monkey. Even further, which type of hominid they found, even from something like a skull fragment.
At the time, an expedition co-led by Haile-Selassie was digging at Woranso-Mille, a field site in Ethiopia’s Afar region less than three miles from Miro Dora, where Bereino was herding. According to Haile-Selassie, Bereino had tried for years to get himself hired on Haile-Selassie’s team. He sometimes claimed that fossils emerged from eroded rock; when Haile-Selassie had visited in the past, he hadn’t see any.
On this particular day, Bereino was digging an addition to a temporary goat pen when he noticed a bone exposed in the sandstone surface. Bereino got in touch with a local government official, who agreed that it might be something Haile-Selassie would find interesting.
When the official called Haile-Selassie, he remained skeptical, replying that Bereino should mark where he found the fossil and walk it over to his camp. When Bereino and the official arrived, Haile-Selassie soon realized the magnitude of the find. Bereino had found a maxilla, or upper jawbone, belonging to an ancient hominin.
https://www.nationalgeographic.com/science/2019/08/unprecede...
We have Neanderthal DNA, that we inherited through interbreeding.
Why can't both we and the Neanderthals be descendent from a varied group of very similar apes that interbred as well? Isn't this the most likely scenario?
Sometimes I think scientists fall for the same simplistic patterns of thinking that the men on the street fall for every day.
Like, there is only one solution, there is only one cause, there is only one reason, when in fact reality is much more complex than that.
It doesn’t. That is the crux of this article and almost all the scholarship I’ve encountered on the question over the past few decades.
> Isn't this the most likely scenario?
No. The human genome is unusually homogenous, in part thanks to recent Ice Ages inducing bottlenecks. The simplest explanation, to our proximate evolution, is linear. (The simplest explanation is wrong.)
The fossil evidence, for that matter, while it shows significant overlap, does, broadly, present a remarkably-linear path over about 4 million years, with a series of branching-then-consolidating phases.
Such a group would simply be one species. Having many different species as ancestors also wouldn't explain the exceptional homogeneity of the human genome.
The present discovery though doesn't change things as much as the article tries to imply. It just means the speciation (from the appearance of A. afarensis to the disappearance of A. anamensis) lasted longer than previously thought, or at least that the A. afarensis species appeared earlier than we thought.
All the rest is complete speculation and the discovery doesn't really give any reason to think our ancestry tree might be different than previously thought.
They have first to geographically split to live and evolve in two separate similar environments and then merge while still being compatible.
Sometimes I think that BBC articles don't do a perfect job of precisely explaining the patterns of thinking of scientists.
They don't know better, they try to understand better. Why not?
To me it sounds like someone who clearly has a deeper understanding of the topic than those scientists. And I love that.
It paints a blanket picture, with no qualifications (read a few articles at best), and belittles what the scientists in general "do".
Practising scientists are loath to speculate without good evidence; it lays them open to criticism by peers, and damages their credibility with reviewers. Unfortunately this means that there is often a lot of inertia that slows the change of focus and means that there is some waste as the wrong work gets done (work that is known to be irrelevant by most of the community, but passes review). On the other hand this reticence does mean that there is less flailing around and hype than you see in other areas - such as business IT fads (Big Data, ML, AI, Serverless, Microservices...)
From the article:
>The term "missing link" drives anthropologists crazy when they hear anyone, especially journalists, use it to describe a fossil that is part-ape and part-human.
>Indeed Dr Henry Gee, a senior editor at Nature, once threatened to "rip my liver out and eat it with onions, borlotti beans and a glass of claret" if I did so when reporting a previous discovery.
>There are many reasons for Henry's irritation, but chief among them is the recognition that there are many links in the chain of human evolution and most if not nearly all of them are still missing.
To me this is the gist of the article as well of the stream of recent discoveries and papers released. It's also a pattern that permeates computer science nowadays, applying to different realms, from system design to DevOps to team collaboration.
See:
https://en.wikipedia.org/wiki/Ground-penetrating_radar
https://en.wikipedia.org/wiki/Reflection_seismology
https://corporate.exxonmobil.com/energy-and-environment/tool...
What's the point?
--
I'd love a layperson's identification guide.
Why is a homo floresiensis (aka "hobbit") not just a small person? Surely there are people alive today that could mistaken for "hobbits".
https://en.wikipedia.org/wiki/Homo_floresiensis#Anatomy
Maybe a visual diff tool.
I did just found some charts showing the evolution of select skulls. Hmmm. I guess I want more.
http://wutheringexpectations.blogspot.com/2012/08/this-is-he...
That’s the one great invention, I think: Chicken Little, the giant pulsing living blobs of meat that feed the planet. Pohl and Kornbluth understand the value of their own idea well enough to know that just talking about Chicken Little is not enough. They have to rig the plot so we meet it. Sensitive eaters, avert your gaze:
He swung open her door. “This is her nest,” he said proudly. I looked and gulped.
It was a great concrete dome, concrete-floored. Chicken Little filled most of it. She was a gray-brown, rubbery hemisphere some fifteen yards in diameter. Dozens of pipes ran into her pulsating flesh. You could see that she was alive.
Herrera said to me: “All day I walk around her. I see a part growing fast, it looks good and tender, I slice.” His two-handed blade screamed again. This time it shaved off an inch-thick Chicken Little steak. (Ch. 9)
http://www.technovelgy.com/ct/content.asp?Bnum=1002
Chicken Little, a huge mass of cultured chicken breast, was kept alive by algae skimmed by nearly-slave labor from multistory towers of ponds surrounded by mirrors to focus the sunlight onto the ponds.
"Scum-skimming wasn't hard to learn. You got up at dawn. You gulped a breakfast sliced not long ago from Chicken Little and washed it down with Coffiest. You put on your coveralls and took the cargo net up to your tier. In blazing noon from sunrise to sunset you walked your acres of shallow tanks crusted with algae. If you walked slowly, every thirty seconds or so you spotted a patch at maturity, bursting with yummy carbohydrates. You skimmed the patch with your skimmer and slung it down the well, where it would be baled, or processed into glucose to feed Chicken Little, who would be sliced and packed to feed people from Baffinland to Little America."
-From The Space Merchants, by Frederik Pohl (w/CM Kornbluth). Published by St. Martin's Press in 1952.
It's quite difficult to pin down a precise definition for species. Even genetic definitions don't work so well. Depending on how it is measured chimps hit around 99% genetic similarity with humans. Nature isn't so kind as to provide clean and concrete delineations for us, at least not that we're currently capable of measuring.
Of course if hybrids are infertile they would be considered different species.
If hybrids are fertile, like your example of camels and llamas, then according to what reason would they be considered the same species? Did their evolution diverge and then reconverge?
I guess it depends on your definition of "often".
Also, a Computer Science professor has no business arguing about evolution. Or rather, his opinion is as informed as yours or mine, i.e. not very.
So it's fundamentally dishonest. If this CS professor said "I'm a conservative religious guy [as is the case], I fundamentally believe in Creationism and mainstream science gets in the way of my beliefs" it'd be one thing. We could safely disregard his beliefs in evolution while acknowledging he was honest about choosing his religious beliefs over current science.
It should be noted that another lie of Intelligent Design is that it constantly re-invents itself as the "new thing" but it's as old as the science of evolution. It's essentially Creationism wrapped in new language, but even in this guise it's pretty old. It has been discredited again, and again, and again.
For someone "outside a discipline" to be worth paying attention to, he/she must:
- Accurately describe the current state of the art in said discipline, and explain why they chose to pursue a line of thought at odds with it.
- Take pains not to misrepresent the field they are talking about, and accurately address current beliefs and not outdated views. They must not engage in demolishing strawmen.
- Explain how their current expertise relate to the field they are talking about.
- Be honest about their intentions. If it's about religion, they should say so upfront, so people interested about science can decide whether they find religious arguments relevant.
- Be honest about how they represent the fringe views purportedly backing their own opinion. For example, he claims "Stephen Meyer demolished Darwinism", but Meyer did nothing of the sort -- he is widely thought of as a fringe creationist quack, with no scientific reputation at all within the field of biology. He could instead have argued "Stephen Meyer, contrary to mainstream scientific thought, argues that [something]" instead of saying he "demolished" something (which a cursory search would reveal he didn't). This is a huge red flag.
Your response:
"Almost everything in that article is wrong "
"pseudoscientific arguments"
"Stephen Meyer is not brilliant and he is a quack"
" Computer Science professor has no business arguing about evolution"
"widely discredited and dishonest "
"known to be fundamentally dishonest"
"So it's fundamentally dishonest."
"another lie"
"fringe views"
"fringe creationist quack"
In short, you've proved his point. Your comments -- in any other area of discussion on HN -- would probably get you flagged.
All of this is wrong.
A noteworthy CS professor has zero relevance in a discussion about evolution or biology, particularly when he quotes people who aren't notable in the relevant field and tries to "demolish" strawmen. The word "demolish" is itself a huge red flag.
The sources he quoted are creationist crackpots linked to the Discovery Institute, a notoriously dishonest organization who disguises religion as science.
It is a mistake for the scientific community to engage with crackpots.
> Your comments -- in any other area of discussion on HN -- would probably get you flagged.
No, calling crackpots crackpots -- the mainstream consensus -- won't get me flagged. A big indicator of quackery is a persecution complex ("everyone is against me because of dogma", "they want to suppress dissenting views"). I think it's even in Carl Sagan's baloney detection kit. Sometimes people will call someone a crackpot because they've heard their arguments again and again, debunked them, and still that person insists, with a heavy dose of "the world is conspiring against me". It's ok to call that person a crackpot.
One last thing: in the US the term "Darwinism" (which the article uses) is almost always used by Creationists, and in a pejorative way. From Wikipedia (https://en.wikipedia.org/wiki/Darwinism#Other_uses):
"The term Darwinism is often used in the United States by promoters of creationism, notably by leading members of the intelligent design movement, as an epithet to attack evolution as though it were an ideology (an "ism") of philosophical naturalism, or atheism. For example, UC Berkeley law professor and author Phillip E. Johnson makes this accusation of atheism with reference to Charles Hodge's book What Is Darwinism? (1874). However, unlike Johnson, Hodge confined the term to exclude those like American botanist Asa Gray who combined Christian faith with support for Darwin's natural selection theory, before answering the question posed in the book's title by concluding: "It is Atheism." Creationists use the term Darwinism, often pejoratively, to imply that the theory has been held as true only by Darwin and a core group of his followers, whom they cast as dogmatic and inflexible in their belief."
He doesn't. He showcases his lack of knowledge of biochemistry.
> that is difficult to get serious researchers to grapple with this issue
It is difficult because serious researchers have found out that explaining these issues doesn't lead to understanding for those who refuse to understand these issues.
If I would illustrate that "Nonsense sequences are essentially random" is not true or that "Your task is to invent a new gene by mutation" is a thought experiment completely unrelated to the discussion, would you change your mind, or would you ignore it and focus on some other "obvious and undeniable flaw"?
At this point, why would any serious biologist bother explaining something to people who feel their very existence depends on that something not being true?
https://ncse.com/creationism/legal/cdesign-proponentsists
> For years, "intelligent design" (ID) proponents denied that ID is just a new label for creationism. However, it is now well-known that the first intelligent design "textbook," Of Pandas and People, is just a revised version of a classic "two-model' creationism vs. evolution book named Creation Biology. As Barbara Forrest showed during her testimony in Kitzmiller v. Dover, Pandas was remade into an intelligent design textbook in 1987, in a few months after the Supreme Court ruling against creation science in Edwards v. Aguillard came down.
> The most striking example of the transition was discovered by Dr. Forrest as she compared the drafts of Creation Biology and Of Pandas and People. Not only had "creationism" and "creationist" literally been replaced, apparently via a word processor, with "intelligent design" and "design proponent" in passages that were otherwise unchanged, but she even found a transitional form between the two labels!