> The populations from which the Moroccan and Tanzanian fossils come from may have died out without contributing to the gene pool of living humans.
I find this highly unlikely. The groups inhabited the same continent, potentially for thousands of years. There would almost certainly have been some degree of interbreeding, even if some groups didn't end up contributing very significantly to our modern genome.
Do we know for a fact that all life derives from one organism? Could the conditions that allowed it to come into existence not have occurred in multiple places?
> Do we know for a fact that all life derives from one organism? Could the conditions that allowed it to come into existence not have occurred in multiple places?
In the sense that we have directly observed this organism and can directly trace all life to it? No.
However, the evidence for the LCA is pretty strong. All doubts in my mind were removed when I took molecular genetics of procaryotes in college. Without going into details of finding relevant citations, and hence a fairly lay (and several years divorced from me learning about this stuff), the fact that all domains of life (procaryota, eucaryota, and archaea) share common genetic code and operate similar RNA- and protein-based molecular machinery strongly implies that a single "master template" originated all subsequent life on the planet. Considering how complex a ribosome is, for instance, the fact that all domains of life have similar, but not identical, ribosomal structures seems exceedingly unlikely. Molecular machinery is as complicated as it is because it evolves randomly to fulfill specific tasks. It's highly unlikely that two organisms would evolve the exact same piece of machinery which similar construction and composition to solve a novel task. On the other hand, when evolving from common machinery (i.e. shared ancestors), it's feasible to imagine that two organisms sharing an LCA might independently evolve similar proteins to adapt to a common stimulus. Consequently, eucaryotic cells function broadly similarly to other eucaryotic cells, archaeal cells function broadly similarly to other archaeal cells, and prokaryotic cells function broadly similar to other prokaryotic cells. Finally, archaeal cells function more closely to eucaryotic cells than do prokaryotic cells. Thus, it implies that archaea and eucaryota are more closely related than prokaryota and eucaryota. Hence, the phylogenetic tree. This implies that the most elegant (but not necessarily correct) solution to the similarity between different domains of life is a single unicellular ancestor.
I don't think that actually makes any difference. The earliest common ancestor of humans would still be a single-celled organism, even if we were a composite of several such life forms that evolved totally independently of one another.
Let's say that life arose independently on three separate occasions, and each of these groups evolved as far as a fish completely independently of one another, and these three fish populations were by some miracle similar enough genetically to produce fertile offspring, and they mated, and we're the result. Each of the single-celled organisms that eventually gave rise to these fish would still be a common ancestor of humans, in that all of today's humans are descended from it. Whichever of these organisms appeared first would win the crown of "earliest" common ancestor.
I was going to complain about the (mis)use of the preposition choice “on” over “in”, then I remembered this is the NYT, and in NYC people “stand on line” rather than “stand in line”.
It also follows “Did you work on the computer?” Which asks if you used a computer to do something as well as “Did you work to fix the computer”. I however contend that in the context of the article “in” would be clearer. As in “ghost in the machine”.
Except that "in" would be incorrect – "with a computer", or "using a computer" would be less ambiguous than "on", but unless it was hidden inside the case, "in a computer" doesn't sound right at all.
Similarly, "reconstruct" would be less ambiguous the "find".
>In the title’s structure it suggests to me that they found it physically on top of a computer.
Pheew, good to know it wasn't just me.
I had already imagined an ancient skull found in an abandoned room in the underground of some museum on top of a (as well abandoned) IBM mainframe terminal.
My own nitpick is that 'humanity' is the condition of being humane — and a condition has neither ancestors nor skulls. The correct phrase IMHO would have been 'the skull of man's ancestor' or 'the skull of mankind's ancestor.' Or if one just really really wants to be So Woke It Hurts™ I suppose one could go for 'the skulls of the earliest human ancestor' or somesuch.
> The populations from which the Moroccan and Tanzanian fossils come from may have died out without contributing to the gene pool of living humans.
I find this highly unlikely. The groups inhabited the same continent, potentially for thousands of years. There would almost certainly have been some degree of interbreeding, even if some groups didn't end up contributing very significantly to our modern genome.
i thought this was going to be one of those "i saw Joe had this skull ontop of his screen, and did a double take, i realised it was the missing ..."
I thought it was going to be more like Zoolander:
"In the computer": https://youtu.be/L_o_O7v1ews
or
https://youtu.be/H2uHBhKTSe0
Trivial nitpick, from picture caption:
> A computer reconstruction of a skull that may have belonged to the earliest common ancestor of living humans.
The earliest common ancestor of living humans didn't have a skull, it would have been a single-celled organism.
Do we know for a fact that all life derives from one organism? Could the conditions that allowed it to come into existence not have occurred in multiple places?
> Do we know for a fact that all life derives from one organism? Could the conditions that allowed it to come into existence not have occurred in multiple places?
In the sense that we have directly observed this organism and can directly trace all life to it? No.
However, the evidence for the LCA is pretty strong. All doubts in my mind were removed when I took molecular genetics of procaryotes in college. Without going into details of finding relevant citations, and hence a fairly lay (and several years divorced from me learning about this stuff), the fact that all domains of life (procaryota, eucaryota, and archaea) share common genetic code and operate similar RNA- and protein-based molecular machinery strongly implies that a single "master template" originated all subsequent life on the planet. Considering how complex a ribosome is, for instance, the fact that all domains of life have similar, but not identical, ribosomal structures seems exceedingly unlikely. Molecular machinery is as complicated as it is because it evolves randomly to fulfill specific tasks. It's highly unlikely that two organisms would evolve the exact same piece of machinery which similar construction and composition to solve a novel task. On the other hand, when evolving from common machinery (i.e. shared ancestors), it's feasible to imagine that two organisms sharing an LCA might independently evolve similar proteins to adapt to a common stimulus. Consequently, eucaryotic cells function broadly similarly to other eucaryotic cells, archaeal cells function broadly similarly to other archaeal cells, and prokaryotic cells function broadly similar to other prokaryotic cells. Finally, archaeal cells function more closely to eucaryotic cells than do prokaryotic cells. Thus, it implies that archaea and eucaryota are more closely related than prokaryota and eucaryota. Hence, the phylogenetic tree. This implies that the most elegant (but not necessarily correct) solution to the similarity between different domains of life is a single unicellular ancestor.
I don't think that actually makes any difference. The earliest common ancestor of humans would still be a single-celled organism, even if we were a composite of several such life forms that evolved totally independently of one another.
Yeah but a "common ancestor of humans" would imply some sort of convergence, which could have happened at any point
Let's say that life arose independently on three separate occasions, and each of these groups evolved as far as a fish completely independently of one another, and these three fish populations were by some miracle similar enough genetically to produce fertile offspring, and they mated, and we're the result. Each of the single-celled organisms that eventually gave rise to these fish would still be a common ancestor of humans, in that all of today's humans are descended from it. Whichever of these organisms appeared first would win the crown of "earliest" common ancestor.
Could you be any more pedantic?
Is it pedantic? I can't read it any other way, what's 'earliest' supposed to mean?
I was going to complain about the (mis)use of the preposition choice “on” over “in”, then I remembered this is the NYT, and in NYC people “stand on line” rather than “stand in line”.
It also follows “Did you work on the computer?” Which asks if you used a computer to do something as well as “Did you work to fix the computer”. I however contend that in the context of the article “in” would be clearer. As in “ghost in the machine”.
Except that "in" would be incorrect – "with a computer", or "using a computer" would be less ambiguous than "on", but unless it was hidden inside the case, "in a computer" doesn't sound right at all.
Similarly, "reconstruct" would be less ambiguous the "find".
They found it in the computation performed by a computer rather than they found it on the computation.
In the title’s structure it suggests to me that they found it physically on top of a computer.
>In the title’s structure it suggests to me that they found it physically on top of a computer.
Pheew, good to know it wasn't just me.
I had already imagined an ancient skull found in an abandoned room in the underground of some museum on top of a (as well abandoned) IBM mainframe terminal.
My own nitpick is that 'humanity' is the condition of being humane — and a condition has neither ancestors nor skulls. The correct phrase IMHO would have been 'the skull of man's ancestor' or 'the skull of mankind's ancestor.' Or if one just really really wants to be So Woke It Hurts™ I suppose one could go for 'the skulls of the earliest human ancestor' or somesuch.
Humanity has multiple definitions. According to Merriam-Webster, #4 would be the applicable one in this context.
https://www.merriam-webster.com/dictionary/humanity
Please don't post stuff with pay walls infront of it...