Are we homo faber or homo sapiens?

[Laer Carroll]

I read an article a couple of months ago that made an assertion relevant to a story I'm writing now. I wonder what the anthropologists and anthro-savvy in this forum make of it, and what terminology they'd use in discussing the assertion.

It referenced The Naked Ape by Desmond Morris. In his book he said that humans evolved into existence because we use tools so extensively. Not only do they shape the world, but they shape us by evolving us better able to make and use tools.

So instead of growing fur we take it from other animals, or make substitutes for fur. Since some kinds of clothing (bikinis, desert robes, parkas, spacesuits) can be exchanged for other kinds we don't need fur. Which leads to other aspects of humanity. It makes us sensualists and so makes us have sex more. (Morris talked a lot about sex, and I could never understand why or his arguments about why.)

At any rate the recent article said we should be classified homo faber rather than homo sapiens. It suggested that visiting aliens might not think we were sapient, being little more than beavers with hands. Our cities might seem to them more like ant hills, the result of instinctive instead of thinking behavior. And thus they'd be justified in exterminating or enslaving us.

So what? Faber or sapiens? Both or neither? And what is the accepted anthro terms for humans and their ancestors and siblings? Do you agree with the terminology?

 

[Helix]

If this a taxonomic question, the answer is Homo sapiens.

 

[AwP_writer]

I go with sapiens. For one, we are not the only animal to use tools, we're just by far the best at it. Secondly, our tool use is the result, not the cause. Without our bigger brains we'd be using sticks to get ants out of ant hills and probably not too much more. I'm pretty sure the official term for humans and related species is hominid.

 

[Albedo]

The implicit claim we're the only (or even a particularly) sapient hominid is horseshit, but regardless the first-used species name has priority. Unless you could show that technological humans are biologically distinct from pre-technological ones, we're sapiens.

Re: the sex, pop sci writers of a certain era all write with this super-earnest essentialism/reductionism about sex and how we all think it's the best thing since sliced bread (or fur coats, wtf). I'm not quite sure who they're trying to convince.

 

[Albedo]

But wait, isn't Ol' Linnaeus himself the type specimen for H. sapiens? You'd have to prove that modern man is biologically distinct from an 18th century Swedish dude.

 

[Chris P]

Jared Diamond's book The Third Chimpanzee makes the argument that aliens would put us in the same genus, Pan, as chimps and pygmy chimps, making us Pan sapiens. As a biologist, I've learned that taxonomy is largely an academic game that shows relationships, historically based on body form, but with genetic techniques now we can better relate taxonomy to evolutionary history. As for the naming, whether we're Homo sapiens, Pan sapiens, Homo faber or Homo chrispi could be argued any way one would like to.

 

[Albedo]

Mmm, chrispi.

 

[Helix]

Jared Diamond's book The Third Chimpanzee makes the argument that aliens would put us in the same genus, Pan, as chimps and pygmy chimps, making us Pan sapiens. As a biologist, I've learned that taxonomy is largely an academic game that shows relationships, historically based on body form, but with genetic techniques now we can better relate taxonomy to evolutionary history. As for the naming, whether we're Homo sapiens, Pan sapiens, Homo faber or Homo chrispi could be argued any way one would like to.

But the names only have currency if they're within the rules of nomenclature as laid out in the red book, the ICZN. Homo faber is a nomen nudum, I'd think. Homo sapiens would only become Pan sapiens if the genus Pan was described before Homo.

 

[Chris P]

But the names only have currency if they're within the rules of nomenclature as laid out in the red book, the ICZN. Homo faber is a nomen nudum, I'd think. Homo sapiens would only become Pan sapiens if the genus Pan was described before Homo.

So for Homo faber to exist, someone would have to describe a new species as being within the currently described H. sapiens (and have it recognized by ICZN)? The remainder would remain Homo sapiens? I know taxonomists are either lumpers or splitters, and new species are broken out of existing species all the time.

What about a species changing genus? I'm thinking about Heliothis zea becoming Helicoverpa zea about 30 years ago. Did Helicoverpa have to be described before Heliothis for zea to be moved? Otherwise zea would have remained in Heliothis? They couldn't create a brand new genus? I know this gets complicated, and is part of why I did so poorly in my systematics class (worst grade of my entire college career).

 

[indianroads]

The use of tools altered the way we think and reason - but we first picked up that tool because our brain reasoned a use for it. Seems like a chicken or the egg issue. I'd go with Sapiens.

It suggested that visiting aliens might not think we were sapient, being little more than beavers with hands. Our cities might seem to them more like ant hills, the result of instinctive instead of thinking behavior. And thus they'd be justified in exterminating or enslaving us.

In one of Michio Kaku's books (forget which one) he wrote about why aliens have NOT visited us. He used the analogy of: If you're building a superhighway through the desert, and come across an ant hill at the edge of your construction zone, would you approach the ant hill and offer them trinkets? I laughed, but he's got a point. If I placed a cell phone on an ant hill, would they find any use for it?

IMO life in the universe is probably fairly common - BUT life that is of an intelligence we could understand would probably be rare. We're separated not only by vast distances, but time as well. Humanity has only been 'civilized' for a few thousand years (I'm being generous.. when I watch the news it seems as if we've not reached that level yet), and that amount of time is like a nanosecond in a day, so crossing paths with an alien race we can communicate with seem unlikely to me.

 

[Chris P]

In one of Michio Kaku's books (forget which one) he wrote about why aliens have NOT visited us. He used the analogy of: If you're building a superhighway through the desert, and come across an ant hill at the edge of your construction zone, would you approach the ant hill and offer them trinkets? I laughed, but he's got a point. If I placed a cell phone on an ant hill, would they find any use for it?

IMO life in the universe is probably fairly common - BUT life that is of an intelligence we could understand would probably be rare. We're separated not only by vast distances, but time as well. Humanity has only been 'civilized' for a few thousand years (I'm being generous.. when I watch the news it seems as if we've not reached that level yet), and that amount of time is like a nanosecond in a day, so crossing paths with an alien race we can communicate with seem unlikely to me.

Another theory of why we haven't been contacted (it sounds like maybe an extension of the Fermi Paradox) is that humans have only been able to send and receive electromagnetic signals for about 100 years. In the 15 billion years of the universe, other life forms might have adopted this capability then abandoned it (for better technology that we don't know about yet, or their species died out, etc.), the signals to zip past Earth never to return long before we were able to detect it. Or we are doing it long before others are able to detect it, and we might abandon it (for better technology that we don't know about yet, or our species dies out, etc.) long before they can respond. Basically it would be like throwing two grape seeds into the Grand Canyon and expecting them to collide.

 

[Helix]

I will put my taxonomist's hat on for this. (It's very fetching.) But I'm waiting for the NBN installer, so might have to nip off half-way through.

So for Homo faber to exist, someone would have to describe a new species as being within the currently described H. sapiens (and have it recognized by ICZN)? The remainder would remain Homo sapiens? I know taxonomists are either lumpers or splitters, and new species are broken out of existing species all the time.

It certainly is possible that someone would split off a new species from Homo sapiens and, as long as the description met all the criteria laid down in the Code, it would be a totes legit name.

On lumpers and splitters, sometimes we lump and sometimes we split! It depends on what the evidence says. And how that evidence is interpreted, of course. I've lumped a whole bunch of species in one group and split some others. There's a certain amount of subjectivity required, even in these days of molecular analysis. All taxonomies and phylogenetic trees are hypotheses.

What about a species changing genus? I'm thinking about Heliothis zea becoming Helicoverpa zea about 30 years ago. Did Helicoverpa have to be described before Heliothis for zea to be moved? Otherwise zea would have remained in Heliothis? They couldn't create a brand new genus? I know this gets complicated, and is part of why I did so poorly in my systematics class (worst grade of my entire college career).

I'll have to look at that example to see what the case is. (The NBN people have just called and will be here in minutes!) But there are several reasons that species change genera. The most straightforward case is if it was misclassified in the first place.

(Will be back with a brand new internet connection -- hopefully -- in a while!)

 

[Helix]

I'm back! No NBN, no brand new internet connection.

So, Helicoverpa zea...Had a look and in this case it appears to be a correction to misclassification. That's fair enough, because Heliothis seems to be a grab bag of small pale noctuid moths that smear themselves across the car headlights at night in cropping areas. Not a moth taxonomist, but I reckon that's a lousy diagnostic characteristic.

When you see a species with the author's name in brackets, it means that the species has been moved to another genus.

No need to create a brand new genus if the species fits into an already existing one. Taxonomy (and especially systematics) should reflect relationships.

 

[neandermagnon]

So instead of growing fur we take it from other animals, or make substitutes for fur. Since some kinds of clothing (bikinis, desert robes, parkas, spacesuits) can be exchanged for other kinds we don't need fur.

Human's had already lost their thick body hair long before clothes were invented. The modern pattern of human hair didn't evolve because of clothes. The most likely explanation is the need to stay cool while running (though there are other possible explanations).

Unlike most mammals, humans are adapted for long distance running (as opposed to sprinting) and early humans (Homo ergaster or thereabouts) are thought to have hunted using the persistence hunting method (still in use by some modern hunter-gatherers, e.g. !kung San) where you run after your prey repeatedly, not by sprinting, but by keeping on tracking it down never letting it rest for hours or even days until it dies of heat exhaustion. Humans' bipedal posture and pattern of hair growth (thick hair on the head, not much hair on the rest of the body) combined with the fact that we sweat over our whole bodies (most mammals don't) is perfect for keeping cool under the midday sun, giving humans a big advantage over the animals they were hunting, who were a lot more susceptible to heat exhaustion. Most mammals stay out of the midday sun, but it's thought early humans learned that other animals were easier pickings if they hunted at midday.

This sort of thing probably goes back nearly 2 million years and is lower palaeolithic. Humans didn't begin to process animal skins until the middle palaeolithic era and it's likely that the earliest processing of animal skins was more for carrying things (babies, gathered food etc) than clothes. The Neandertals very likely made clothes. They lived in Europe during the ice ages (sub-arctic climate) so it's not really surprising, but it wouldn't be a case of them losing body hair because they worse clothes. It's more likely that they re-evolved thicker body hair and wore clothes as well (in addition to various other cold-adapted traits they evolved) because it was bloody cold. They didn't have needles or any evidence of stitched clothing. The more warm-adapted, probably less hairy early Homo sapiens invented stitched clothing.

Even though there are other possible explanations given for why we evolved the pattern of body hair that we have, there's no doubt about the fact that it evolved long before humans started wearing clothes. Same as how hominins were fully bipedal millions of years before they started making stone tools (contrary to the earlier belief that our ancestors became bipedal to free up the hands for tool use). Human evolution is a very fast moving field and I personally would recommend being very careful that any book or article is based on up-to-date information (by up-to-date I mean from the last ten years or so).

Regarding your point about the name of our species, I've always considered that our species is anything but wise. I think it's hilarious that we named ourselves that, especially having the subspecies name "sapiens" as well, making us wise, wise man, as though saying it once wasn't enough. In my story about the cloned Neandertal, he regularly takes the blatant piss out of Homo sapiens for naming themselves that when it so obviously isn't true. I once wrote a blog post where I gave our subspecies the name Anthropos ingeniosa arrogans (arrogant, ingenious man) - we are ingenious. We're just not wise. And we're pretty arrogant.

It's extremely unlikely that Homo sapiens sapiens is going to be renamed. The fact that we're anything but wise is not a reason to rename a species. Species only get renamed if it turns out they're not really a species after all, for example Homo habilis, Homo ergaster and Homo rudolphensis are now thought to be a single species which is a lot more varied than previously thought (as evidenced by the amount of variation found in a single archaeological site (Dmanisi in Georgia - the Georgia in Europe that is). If they all get subsumed into a single species then obviously some will be renamed, but they won't get a new name. They'll all be reclassified under one of those names. I think the tradition is to use the name that was coined first in these circumstances (biologists are very traditional about these things) though IMO Homo ergaster is the most fitting name.

And as Helix mentioned upthread, there are "lumpers" and "splitters" so there is debate about whether these should all be subsumed under one species - I'm in favour of lumping them.

Fitting doesn't come into renaming species. Common chimpanzees are Pan troglodytes. Troglodytes means cave dweller, and chimps don't live in caves, but no-one cares about that. It's their name and they will only change it if they turn out not to be a species. Pan paniscus (bonobos) got a new name when it was established that they were a different species. If you identify a species or genus, you get to name it. Homo erectus started off being called Pithecanthropus erectus but when later it was determined that it should be in the same genus as modern humans, it got renamed as Homo erectus. Similarly, there's some debate about whether Neandertals should be Homo neanderthalensis or Homo sapiens neanderthalensis - but that's not about the name, it's about whether they're technically the same species as us (same species, different subspecies) or a different species altogether.

Anyway, due to the established rules and traditions surrounding the naming system for species, our species name isn't going to get changed.

 

[Laer Carroll]

I can't help thinking that our use of tools is so crucial to our survival that this must have had some effects on our bodies, and those effects made their way into our genes. I'd guess our hands and eyes especially would be affected.

I'd guess even more changes would have affected our brains and the parts of the body which support our brains. Those would be harder to assess, not being readily observable, and the fossil evidence so sparse. Was our visual cortex affected more by tool use, or by our evolution from tree climbers who needed good 3D and color judgment?

 

[neandermagnon]

I can't help thinking that our use of tools is so crucial to our survival that this must have had some effects on our bodies, and those effects made their way into our genes. I'd guess our hands and eyes especially would be affected.

We were already fully bipedal, however the human hand is adapted for flintknapping (as in several differences between chimp hands and human hands come from the fact that human hands have become less adapted for climbing and more adapted for flintknapping). The main thing is having both strength and control in the hands to hit the flint very precisely yet hard enough to break the rock. Lower and middle-palaeolithic flintknapping techniques require the rocks to be hit together pretty hard, at exactly the right point and angle to break the rock in the right way. The way you have to hold the rocks - well human hands are just the right shape for it. Human hands the same shape as modern hands evolved in the human lineage not long after human ancestors started flintknapping - this strongly suggests natural selection in favour of this hand shape for flintknapping.

Bear in mind that other ape species and quite a few other species not even related to humans make and use simple tools. However, flintknapping is specifically human as in austalopithecines started doing it shortly before evolving into early humans, and all human species have done it*. IMO it definitely shaped our evolution. Not just directly (such as the evolution of the shape of the hand) but indirectly as in the stone tool users were able to break bones to get at the brains and marrow (an excellent source of calories and protein that doesn't require much chewing) and this led to the expansion of human brains because a large temporoparietalis muscle was no longer needed - the muscle controls the jaw and in chimps and gorillas it is big so they can chew up coarse foods (gorillas especially) and this is a constraint on brain size. Softer food = smaller muscle = brains can get bigger.

*so much so that it's a defining characteristic of the human genus, along with brain size and a few other characteristics.

I also think that we have become somewhat neurologically adapted for flintknapping. It requires a lot of focus on the task at hand, and also breaking rocks - even the sound and feel of chips of rock being broken off in the right way - is very satisfying. Like there's an inbuilt neurological reward for doing it. Human brains have evolved to be better at sustained, focused attention and as flintkapping stared just before the brain started getting bigger, this may be part of the reason why, along with the thing about the chewing muscles.

There are a lot of changes that all happened at once so it's very hard to link specific changes in anatomy with specific behaviours but the shape of our hands appears to come from flintknapping, and also our love of making things and crafts generally is a side effect of neurological changes that were selected for when the ability to make stone tools was crucial for survival. This is why IMO flintknapping is the mother and father of all crafts. But the overall picture is definitely that flintknapping shaped humans... so much so that I'd argue that if rocks like flint* didn't break in a predictable way to leave a sharp edge, humans wouldn't have evolved.

*any knappable rock, it's not just flint

I'd guess even more changes would have affected our brains and the parts of the body which support our brains. Those would be harder to assess, not being readily observable, and the fossil evidence so sparse. Was our visual cortex affected more by tool use, or by our evolution from tree climbers who needed good 3D and color judgment?

Primates see in colour and this evolved mainly to recognise ripe fruit (as in the specific wavelenths we see as different colours relate to ripeness of fruit) but also as trees are a complex 3D environment, many aspects of primate (including humans) visual system (both eyes and brain) evolved to navigate this. I'm not aware of any major adaptations to this in humans compared to other great ape species. But more subtle changes, yeah it's very plausible.

 

[Curlz]

Homo Ludens

 

[indianroads]

I can't help thinking that our use of tools is so crucial to our survival that this must have had some effects on our bodies, and those effects made their way into our genes. I'd guess our hands and eyes especially would be affected.

I'd guess even more changes would have affected our brains and the parts of the body which support our brains. Those would be harder to assess, not being readily observable, and the fossil evidence so sparse. Was our visual cortex affected more by tool use, or by our evolution from tree climbers who needed good 3D and color judgment?

I've read somewhere that our brains are working differently because of all our cell phone use. How many of us had all our friends phone numbers memorized when we were young? Now, I struggle to remember my wife's cell number. So I think our tools (technology) is already having an affect on our evolution - now whether we're evolving or devolving might be a matter of contention.

 

[Laer Carroll]

I ... think that we have become somewhat neurologically adapted for flintknapping. It requires a lot of focus on the task at hand, and also breaking rocks - even the sound and feel of chips of rock being broken off in the right way - is very satisfying. Like there's an inbuilt neurological reward for doing it. Human brains have evolved to be better at sustained, focused attention and as flintkapping started just before the brain started getting bigger, this may be part of the reason why...

There are a lot of changes that all happened at once so it's very hard to link specific changes in anatomy with specific behaviours but the shape of our hands appears to come from flintknapping, and also our love of making things and crafts generally is a side effect of neurological changes that were selected for when the ability to make stone tools was crucial for survival.

Primates see in colour and this evolved mainly to recognise ripe fruit (as in the specific wavelenths we see as different colours relate to ripeness of fruit) but also as trees are a complex 3D environment, many aspects of primate (including humans) visual system (both eyes and brain) evolved to navigate this.

I suspect you have answered a question I've sometimes wondered. If beauty is unimportant, why are so many businesses devoted to creating and selling beautiful sights, sounds, smells, sensations, and so on? Because beauty brings us back again and again to activities which reinforce important survival skills.

(And so we writers are front and center in human evolution. How's that for a self-serving rationalization?!)

I've read somewhere that our brains are working differently because of all our cell phone use.

I'm sure you're right. We can expand that idea to EVERY device we use that helps us remember, think, communicate, or learn.

Smart phones are only the latest "mind tool." Earlier ones include calculators and abacuses, clay tablets, paintings on cave walls, pen and ink, Post-it notes, and other kinds of hardware. Many kinds of software residing in computers also expand our minds' abilities. So does the kind of software that resides within our brains. We might call that "brainware": multiplication tables, mnemonic rhymes, Arabic and Roman numerals, musical notation, and so many more.

Over millennia the people who inherited better ability to use mind tools survived better than those who did not, causing our brains to evolve.

How many of us had all our friends phone numbers memorized when we were young? Now, I struggle to remember my wife's cell number.

That's a good thing, not a bad one. A perfect memory is a handicap, despite movies and TV shows and books that portray mental prodigies as having a perfect memory. It's just the opposite. Successful prodigies have better-than-average "forgetters." Because every second we take in over a million bits of information. Most of that is unimportant, or if important only for a short time, maybe even seconds. When memories of unimportant stuff fades, the important memories rise like islands emerging from the sea as the tide rolls out.

I'll bet that everyone here has had a common experience. We take a break from a problem, maybe overnight, maybe for a week or a month, and when we return to the problem, it has become simpler. So much perhaps that the solution is obvious.

Another ability successful prodigies have is the ability to see patterns. Several experiments in the '50s with chess masters showed they do not have an extraordinary memory. Instead what they have is the ability to divide a game into "chunks" at several levels of play. Near the lowest they can almost literally see how individual pieces form combinations such as a fork where one piece threatens two or more pieces. At the middle level how several combinations like forks command (or don't) the middle of the board. And at the highest level how a game divides into begin-game / mid-game / end-game, each requiring different strategies.

Bottom line: our future was written when the first wo/man took up a clay tablet and stylus to aid hi/r memory, an abacus to aid hi/r computing power, and bestrode a horse to aid hi/r muscles. S/he was the first cyborg. Only instead of having hi/r mechanical aids being surgically implanted, they can be put on and taken off. And replaced with a pocket supercomputer and a Tesla runabout - or a spaceship with a symbiotic super-AI.

 

[PorterStarrByrd]

An arriving alien would quickly recognize humans as the dominant species on earth (except for may cockroaches) while finding all life inferior to theirs unless they evolved without war in their development. Ahead of us in technology who knows where they would stand in terms of strategy development or many other things. We might or might not be edible, The concept of what they would consider us would devolve from things we can't imagine and perhaps observations we don't anticipate. Leaving that aside we are homo sapiens because we can say we are homo sapiens, a term meaningless anywhere but on this planet.

 

[Chris P]

Thanks for looking into the Heliothis issue, Helix!

There are two points discussed in this thread that go against my understanding of evolution.

First, the adaptation always comes first, and those adaptations that increase the likelihood of the individual survivng to reproductive age get passed on. That's why there is some genetic resistance to the childhood killer malaria in the African tropics (which unfortunately is caused by the same adaptation that leads to sickle cell anemia that kills after reaching reproductive age) and no known genetic resistance to later-life conditions such as cancer or Alzheimer's. So the idea that tool use altered us isn't correct; adaptations that allowed tool use to develop were preserved, and further adaptations of the adaptations allowed even more tool use. The use itself doesn't cause adaptations that are preserved or selected out, only allows selection to work.

Second, natural selection isn't the only force at work. Darwin himself described sexual selection, or the preservation of traits that don't increase success in the survival of the fittest sense, but increase reproduction by the possessor having more sex. Survival of the cutest, if you will. Whatever standards of beauty that persist for multiple generations in a society will be preserved. I had a conversation once with someone who said men stereotypically like large breasts because it indicates higher milk production and therefore higher infant survival. I countered this argument by saying that Southeast Asian women are stereotypically small breasted yet are the most populous people in the world. This of course doesn't mean that small breasts are evolutionarily favorable (and I'm sure someone's done studies correlation breast size and milk production and infant survival) but that for whatever reason those populations favored a certain breast size while others favored other sizes. There is much more on play here, such as Founder's Principles, etc., and because humans have the power of reason the random factor is through the roof. This is a greatly simplified example, to be sure.

 

[AwP_writer]

I don't think the change in brain wiring is actually evolution, it's just adapting to the current environment. If a lot of tech just disappeared overnight, we'd all have problems, but young kids and those born after would be fine because they'd wire their brains for their current environment. It's not an evolutionary change, it's not even genetic drift. A good chunk of our brains evolved long ago to have "blank" areas meant to be filled in by the current environment.

 

[Roxxsmom]

I don't think the change in brain wiring is actually evolution, it's just adapting to the current environment. If a lot of tech just disappeared overnight, we'd all have problems, but young kids and those born after would be fine because they'd wire their brains for their current environment. It's not an evolutionary change, it's not even genetic drift. A good chunk of our brains evolved long ago to have "blank" areas meant to be filled in by the current environment.

Nope, wouldn't be evolution. Evolution happens as genetic changes occur in a population across generations, and (assuming Darwin was correct, as all evidence suggests), as a result of differential survival and reproductive success.

So it's possible that cell phones might affect the evolution of the human nervous systems across many generations (far more than the technology has been available) if there is a way they allow people with certain genetically determined brain configurations to have more children, who in turn inherit said configuration and experience greater reproductive success and pass it on to their kids and so on.

The problem is, even if this is possible, the technology is currently changing in a much faster timeframe than our ability to pass on genes that would confer differential success in the presence of such technology. Changes in neural wiring is a proximal effect that occurs within the lifetime of the person using the technology, which isn't evolution.

 

[Beanie5]

I think Homo ludicrus is the most apt.

 

[neandermagnon]

Thanks for looking into the Heliothis issue, Helix!

There are two points discussed in this thread that go against my understanding of evolution.

First, the adaptation always comes first, and those adaptations that increase the likelihood of the individual survivng to reproductive age get passed on. That's why there is some genetic resistance to the childhood killer malaria in the African tropics (which unfortunately is caused by the same adaptation that leads to sickle cell anemia that kills after reaching reproductive age) and no known genetic resistance to later-life conditions such as cancer or Alzheimer's. So the idea that tool use altered us isn't correct; adaptations that allowed tool use to develop were preserved, and further adaptations of the adaptations allowed even more tool use. The use itself doesn't cause adaptations that are preserved or selected out, only allows selection to work.

When you look at the fossil record, the behaviour comes first, i.e. tool use happens first, then the anatomy changes soon after (soon, in evolutionary terms, which is not "soon" in a normal context) - what happens is that animals (a species of australopithecus in this case) start doing something (making flint tools to break bones to get at brains and marrow in this case) which gives them a survival advantage. They are within the normal range of variation for their species (bear in mind that all species have variation).

Over time, those who are better adapted to do the behaviour well (hands and brain wiring that make learning to knap flint easier) have a bigger survival advantage, generation upon generation of the better adapted survivors breeding with better adapted survivors leads eventually to changes in anatomy that can be observed in the fossil record (in this case, the emergence of the earliest members of the genus Homo - slightly bigger brains/skulls, hands more like modern human hands, smaller teeth and smaller chewing muscles).

It's likely that the first australopiths to make flint tools had above average intelligence for their species, but still within the normal range. Nothing special. It's possible an environmental change led to the change of behaviour, e.g. food being a bit scarcer than usual. All extant great ape species use basic tools and were highly likely to be doing so before hominins split from the chimp lineage (which was about 7 million years ago - the time when Australopithicus was doing all this stuff was approx 3 million years ago). The new behaviour is just a tiny extension of existing ape behaviour. It gave the australopiths that knapped flint enough of a survival advantage to set them on an evolutionary trajectory that led to the evolution of humans.

It's not that different to the way that a change in environment results in adaptations to the new environment... the change happens first, then the evolutionary changes happen after. But in this case the change of behaviour and the survival advantage that comes from it that results in evolutionary change further down the line.

Also bear in mind that evolutionary adaptation isn't one big change. It's the sum total of a lot of tiny changes.