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3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

bbc.co.uk

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Re: 3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

#111

Post by dwaltrip »

not_a_cop75 wrote: post #80
olooney wrote: post #73

Earlier quoted context omitted.

My impression is that we just don't have enough data to draw an accurate timeline, much less a tree, and are an order of magnitude away from being able to study second-order phenomenon like introgression. I think fewer than 10,000 early hominid individuals have been found, most with very partial skeletons. And they aren't distributed uniformly across time and space; you might find a dozen in one cave, then nothing fo…

Is it wrong to believe at this point that instead of macro evolution, we could be looking at several differing extinction points?

I believe "macro evolution" is a bit of a controversial term, as it that term and the corresponding "micro evolution" have been co-opted by creationists, who obtusely claim that there is no evidence for macro evolution, but that they accept micro evolution.

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.

Re: 3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

#112

Post by Robotbeat »

dalbasal wrote: post #19
vanderZwan wrote: post #3

The impression I got from a recent PBS Eons video on the non-existing missing link[0] is that interbreeding happened all the time and that a very realistic possibility for the answer is "most, possibly all of them" . [0] https://www.youtube.com/watch?v=pwW40Dj5Sro

At >4mybp, this species may have been genetically close enough to interbreed with chimp ancestors. If it overlapped with afarensis and other australopithecines, hybridisation almost certainly would have been possible. These guys were as closely related (at least in the earliest periods) to eachother as we were to Neanderthals, denisovans and the other undiscovered species who we know our ancestors mixed with. Homo ha…

To what extent does number of chromosomes matter, here? I'm still confused about how species with different number of chromosomes can successfully interbreed without major problems in their offspring and thus I am still confused about the process of how a species can change its number of chromosomes (since the genetic problems that might occur with such crossbreeding would not likely be terribly helpful in survival). Is there any really good explanation for this that someone can point me to?

Re: 3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

#113

Post by Balgair »

vanderZwan wrote: post #3

The impression I got from a recent PBS Eons video on the non-existing missing link[0] is that interbreeding happened all the time and that a very realistic possibility for the answer is "most, possibly all of them" . [0] https://www.youtube.com/watch?v=pwW40Dj5Sro

PBS Eons is an amazing show! Their other episodes on Purple Earth, the Devil Hogs, etc are great!

I love my boy Steve!

Re: 3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

#114

Post by the_af »

barking wrote: post #107
the_af wrote: post #88

Earlier quoted context omitted.

Ugh, no. Intelligent Design strikes again I see. Almost everything in that article is wrong (and also, the same tired pseudoscientific arguments), starting from the fact he claims "Darwinism" is a "credo". Also, Stephen Meyer is not brilliant and he is a quack. 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.

Sometimes it's no harm to have eyes from outside a discipline have a look at things.

But this guy mostly took a look at things from widely discredited and dishonest Intelligent Design and Creationist sources (every single person he mentions in his article). ID organizations like the Discovery Institute (of which he quotes people related to) is known to be fundamentally dishonest in trying to hide religious beliefs and pass them as science.

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.

Re: 3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

#115

Post by the_af »

siempreb wrote: post #106
the_af wrote: post #99

Earlier quoted context omitted.

> Well established? It's simply not proven, period. You should only teach kids what you are 100% sure about Forget teaching science at all, then. That's not how scientific knowledge works. Evolution is not "proven". No empirical science theories are ever "proven". But evolution as a theory is pretty much as good as it gets. Yes, some details get reworked from time to time, but the fundamentals are our best bet. > Gra…

> Other people have told you multiple times no-one believes apes evolved into humans You're kidding me? That's what I see with most ape -> human believers, they are 100% sure about things they assume or cannot know. Typical example, thx for that.

Me:

> Other people have told you multiple times no-one believes apes evolved into humans, so please stop arguing against this strawman

You:

> That's what I see with most ape -> human believers

Do you see the problem in this exchange?

Re: 3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

#117

Post by dalbasal »

olooney wrote: post #73
dalbasal wrote: post #16

>The reason for this likely elevated status is because we can now say that anamensis and afarensis actually overlapped in time. 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…

My impression is that we just don't have enough data to draw an accurate timeline, much less a tree, and are an order of magnitude away from being able to study second-order phenomenon like introgression. I think fewer than 10,000 early hominid individuals have been found, most with very partial skeletons. And they aren't distributed uniformly across time and space; you might find a dozen in one cave, then nothing fo…

Definitely not enough to draw an accurate timeline, but enough for educated guesses. As you say, guestimates shift with major discoveries, but not quite as much as pop-science press would have you think.

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.

Re: 3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

#118

Post by dalbasal »

Robotbeat wrote: post #112
dalbasal wrote: post #19

Earlier quoted context omitted.

At >4mybp, this species may have been genetically close enough to interbreed with chimp ancestors. If it overlapped with afarensis and other australopithecines, hybridisation almost certainly would have been possible. These guys were as closely related (at least in the earliest periods) to eachother as we were to Neanderthals, denisovans and the other undiscovered species who we know our ancestors mixed with. Homo ha…

To what extent does number of chromosomes matter, here? I'm still confused about how species with different number of chromosomes can successfully interbreed without major problems in their offspring and thus I am still confused about the process of how a species can change its number of chromosomes (since the genetic problems that might occur with such crossbreeding would not likely be terribly helpful in survival).…

Having a different number of chromosomes is a hurdle, but not an absolute barrier to offspring reproductive viability. It's not necessarily an issue for animal health.

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.

Re: 3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

#119

Post by lurquer »

the_af wrote: post #114
barking wrote: post #107

Earlier quoted context omitted.

Sometimes it's no harm to have eyes from outside a discipline have a look at things.

But this guy mostly took a look at things from widely discredited and dishonest Intelligent Design and Creationist sources (every single person he mentions in his article). ID organizations like the Discovery Institute (of which he quotes people related to) is known to be fundamentally dishonest in trying to hide religious beliefs and pass them as science. So it's fundamentally dishonest. If this CS professor said "I…

Let me get this straight... a noteworthy CS professor points out some obvious and undeniable flaws in the current theory or protein 'evolution.' He also points out that is difficult to get serious researchers to grapple with this issue because Darwinism has turned into a dogma where people are viciously attacked if they point out some fundamental flaws with the idea.

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.

Re: 3.8M-year-old skull of an early ape-like human ancestor discovered in Ethiopia

#120

Post by michaelmrose »

siempreb wrote: post #60
tspiteri wrote: post #45

Earlier quoted context omitted.

Are you implying that if we don't know all the details of something, then we just don't know it? That is, are you implying that if we don't know all the details about our evolution, then we should just say that we know nothing and ignore all the things we actually do know are very very likely? That would leave you without any empirical sciences, because there has always something we do not know. When Newtonian mechan…

> if we don't know all the details about our evolution, then we should just say that we know nothing and ignore all the things we actually do know are very very likely? Nothing wrong with studying and figuring out how things work, you should not look at it with an all or nothing attitude. But assuming from the very start that all human species ancestors are some kind of ape is just so ridiculous that it can only sink…

There is no notable and credible alternative theory that doesn't involve rearranging a graph of apelike creatures.

How about you come clean and admit you aren't advocating for a different theory about the shape of life's family tree but the abdication of the need to make one to a "higher power", an unscientific theory that literally possess the most notable flaw you are ascribing to biology. That one must indoctrinate kids at a young age in order to convince anyone.

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