Another new hominid fossil

[Mallon]

The literal name of the genus is 'southern ape', there is a reason for that. It's 'just an ape' as opposed to being human simply because of anatomical features that are unique to African Apes.

I wouldn't invest too much in the etymology of a name. Hippopotamus literally means "river horse", but it's most certainly not a horse.
Besides, humans are apes, too.

May I remind you that the fossil is dated 1.95 million and 1.78 million years in age. This means that Turkana Boy with a cranial capacity twice that size had already achieved completely human features with a slightly smaller skull. This fossil, while one of the most complete discovered to date, indicates nothing more then Chimpanzee ancestors were bipedal with more gracial features then modern ones. Notice the incisors, the pronounced brow and the other uniquely African Ape features including the chimpanzee size skull.

Turkana Boy actually dates to 1.6 million years, making it 180-450 thousand years younger than Australopithecus sediba. Regardless, even if I grant you that Homo ergaster was contemporaneous with A. sediba, it still makes no difference concerning the identification of A. sediba as an ape with very human features. It may not be a direct ancestor to the human species (we have no way of knowing that), but it is certainly more closely related to humans than to chimps, again, because it shares more features in common with humans. Indeed, all Australopithecus do.

Yea well, so do old world monkeys. It's an ape just like Lucy and the long list of other, falsely so called, 'missing links'. This is yet another instance where a chimpanzee ancestor is mistaken for one of our ancestors in the zeal to evangelize to Darwinism.

What makes Australopithecus a chimp ancestor when it shares more features in common with humans? Are you arguing that chimps are descended from humans?
Check out this article in the American Biology Teacher (specifically, see Table 1):
http://www.nabt.org/websites/instit...y_teacher/2010/February 2010/FebABTonline.pdf
"Lucy" (A. afarensis) shares 14 skeletal characters in common with 'lower' apes, and 22 in common with humans. A. sediba is even more human-like for the reasons I listed above. Australopithecus may have a chimp-like cranial capacity, but it most other respects, it is like a human.

Where are the chimpanzee/orangutan ancestors? We have so many hominids, why don't these lineages. Do you realize that if they had become extinct there would be no record that they even existed, or at least next to none.

We don't know where the chimp ancestors are yet. We've got some teeth, but that's about it. If their current ecology is any clue, chimps likely evolved in the jungles where fossilization is exceedingly rare (too many decomposers, not much in the way of sedimentation). One thing is for sure: Australopithecus isn't a chimp ancestor. It can't be. The genus as a whole takes on a more human appearance with time, not a more chimp-like appearance.

I still don't understand how you can ignore the fact that Australopithecus sediba had a chimpanzee skull millions of years after the mythical split.

As I've shown, A. sediba can only be considered a chimp if you look only at cranial capacity and ignore everything else. In most respects, the skull of A. sebida is very human-like.

 

[juvenissun]

To this curve, there could be many questions. I will start with a basic one:

Why does the capacity increase?

 

[Mallon]

For what it's worth, creation scientist Dr. Todd Wood has a new blog post about this new hominid here:
Todd's Blog: This was predictable
He refers to A. sediba as "one of the most astonishingly human australopiths to date."

 

[philadiddle]

May I remind you that the fossil is dated 1.95 million and 1.78 million years in age. This means that Turkana Boy with a cranial capacity twice that size had already achieved completely human features with a slightly smaller skull.

Hi Mark,

I've read your posts over the years but I need a refresher as to where you stand on a few issues.

Do you think the dating of these fossils is correct?

Do you accept evolution to any capacity at all? (such as all animals evolved but not humans)

 

[lucaspa]

Without the locality info, how do you know it is not a sequential change by time?

But we do have the "locality info". Not only that, but the time info as well.

 

[lucaspa]

The origins of the genus Homo remain as murky as ever," commented Dr. Daniel E. Lieberman, professor of Human Evolutionary Biology at Harvard.(Scientists, Creationists Agree: 'Sediba' is No 'Missing Link')
​

The literal name of the genus is 'southern ape', there is a reason for that. It's 'just an ape' as opposed to being human simply because of anatomical features that are unique to African Apes.

You don't seem to have read the rest of the article you quoted: "But they do claim that “Sediba” shares more derived features with early Homo species than any other australopith species and thus might help reveal the ancestor of that genus."

That destroys the "just an ape" claim. Instead of anatomical features unique to apes, sediba has anatomical features unique to Homo.

May I remind you that the fossil is dated 1.95 million and 1.78 million years in age. This means that Turkana Boy with a cranial capacity twice that size had already achieved completely human features with a slightly smaller skull.

I think you meant "between 1.95 million and 1.78 million". Turkana boy is estimated at 1.6 million years old. So H. ergastor is younger. Also, the features are not "completetly human". H. ergastor is firmly within the genus Homo, but the features are not H. sapiens.

However, that is not an insurmountable obstacle for A. sediba being an ancestor of Homo. Under allopatric speciation the older species can survive quite a while into the period of the descendent species. After all, H. erectus lasted until just 20,000 years ago.

This fossil, while one of the most complete discovered to date, indicates nothing more then Chimpanzee ancestors were bipedal

How can sediba be a chimp ancestor with derived homo features?

I still don't understand how you can ignore the fact that Australopithecus sediba had a chimpanzee skull millions of years after the mythical split.

Because the skull is not totally chimpanzee. The flatness of the face is more homo than pan.

 

[lucaspa]

I think it's time we go to the original article rather than the news reports. It would be good to look at Table 1 in it's entirety, but I do not know how to import it here. So we will have to look at the text. First the authors want to distinguish Au. sediba from the other "gracile" Australopithecines.

"Au. sediba can be distinguished from other species of Australopithecus by a combination of characters presented in Table 1; comparative cranial measures are presented in Table 2. A number of derived characters separate Au. sediba from the older chronospecies Au. anamensis and Au. afarensis. Au. sediba exhibits neither the extreme megadontia, extensive cranial cresting, nor facial prognathism of Au. garhi. "

Next is to compare sediba with the closest morphological species, Au. africanus:
"closest morphological comparison for Au. sediba is Au. africanus, as these taxa share numerous similarities in the cranial vault, facial skeleton, mandible, and teeth (Table 1). "

Now the differences with Au. africanus:
"Nevertheless, Au. sediba can be readily differentiated from Au. africanus on both craniodental and postcranial evidence. Among the more notable differences, we observe that although the cranium is small, the vault is relatively transversely expanded with vertically oriented parietal walls and widely spaced temporal lines; the face lacks the pronounced, flaring zygomatics of Au. africanus; the arrangement of the supraorbital torus, nasoalveolar region, infraorbital region, and zygomatics result in a derived facial mask; the mandibular symphysis is vertically oriented with a slight bony chin and a weak post-incisive planum; and the teeth are differentiated by the weakly defined buccal grooves of the maxillary premolars, the weakly developed median lingual ridge of the mandibular canine, and the small absolute size of the postcanine dentition. "

BUT, and this is the kicker, those same differences also happen to be the differences Homo has with Au. africanus:
"These exact differences also align Au. sediba with the genus Homo (see SOM text S2 for hypodigms used in this study)."

The similarities to Homo do not end with the skull.
"Au. sediba differs from other australopiths, but shares with Homo a number of derived features of the os coxa, including increased buttressing of the ilium and expansion of its posterior portion, relative reduction in the distance between the sacroiliac and hip joints, and reduction of distance from the acetabulum to the ischial tuberosity. These synapomorphies with Homo anticipate the reorganization of the pelvis and lower limb in H. erectus and possibly the emergence of more energetically efficient walking and running in that taxon (17)."

The teeth also have similarities to Homo:
"In broad terms, the teeth of Au. sediba are similar in size to teeth of specimens assigned to Homo but share the closely spaced cusp apices seen in Australopithecus. "

 

[philadiddle]

That destroys the "just an ape" claim. Instead of anatomical features unique to apes, sediba has anatomical features unique to Homo.

Isn't "Homo" a subcatagory of "ape"?

 

[juvenissun]

But we do have the "locality info". Not only that, but the time info as well.

Your response will fit the second question on this diagram:

Why does the the capacity of modern human (close to the zero line to the right) have such a wide spread?

 

[Mallon]

Why does the the capacity of modern human (close to the zero line to the right) have such a wide spread?

Because humans are better sampled.

 

[juvenissun]

Because humans are better sampled.

So if chimps could also be better sampled, then they would also show a wider variation? The samples seems were taken on the same time horizon, so, what is the variation of modern chimps? I guess the range would be significantly smaller.

 

[philadiddle]

Why does the the capacity of modern human (close to the zero line to the right) have such a wide spread?

You are pointing out that the standard deviation of the sample set for hominids in modern times is higher than the standard deviation for fossils that we have fewer of. Should that mean something apart from what Mallon said? Or, since this is a statistical graph, shouldn't we be focusing on and trying to explain the moving average that changes in a smooth curve?

 

[juvenissun]

You are pointing out that the standard deviation of the sample set for hominids in modern times is higher than the standard deviation for fossils that we have fewer of. Should that mean something apart from what Mallon said? Or, since this is a statistical graph, shouldn't we be focusing on and trying to explain the moving average that changes in a smooth curve?

Modern human skulls (fossils) have higher S.D. in capacity because of more samples. (Mallon suggested)
--> Chimps skulls (fossils) have smaller S.D. due to fewer samples.

1. If the amount of samples (of different object) are not the same and all are plotted on the same diagram, then the the so-called "smooth curve" is simply deceptive.

2. One of my question is: Are modern chimp skulls (many samples are available) also have higher S.D. in capacity? My guess is no. It would still have smaller S.D. than human skulls.

3. My earlier (main) question is: why does the curve rise in value (cranial capacity)?

The meaning of #3 is that if we could not answer this question, then the index of cranial capacity is basically meaningless. First, we do not know if the curve is true (#1). Second, we do not know how to interpret it.

So, according to my speculation, this curve should have an obvious kink somewhere close to the modern time. All fossils to the right (younger) side are human skulls and all others to the left (older) are chimp fossils. The appearance of human is sudden and should be clearly seen, rather than a smooth change, on the cranial capacity.

 

[Mallon]

Modern human skulls (fossils) have higher S.D. in capacity because of more samples. (Mallon suggested)
--> Chimps skulls (fossils) have smaller S.D. due to fewer samples.

The fossil skulls don't come from chimps as explained above, juvie.

1. If the amount of samples (of different object) are not the same and all are plotted on the same diagram, then the the so-called "smooth curve" is simply deceptive.

That's not true. The sample means still likely form an exponential curve.

2. One of my question is: Are modern chimp skulls (many samples are available) also have higher S.D. in capacity? My guess is no. It would still have smaller S.D. than human skulls.

Ok. I don't agree, but I don't see why it matters, either.

3. My earlier (main) question is: why does the curve rise in value (cranial capacity)?

Because bigger brains were being evolved.

So, according to my speculation, this curve should have an obvious kink somewhere close to the modern time. All fossils to the right (younger) side are human skulls and all others to the left (older) are chimp fossils. The appearance of human is sudden and should be clearly seen, rather than a smooth change, on the cranial capacity.

Your speculation is wrong. There is no "obvious kink" in the trend line. It's a smooth curve.

 

[juvenissun]

Because bigger brains were being evolved.

Why? Why all of a sudden the size of brain became important?

 

[Mallon]

Why? Why all of a sudden the size of brain became important?

Because intelligence is adaptive.

 

[juvenissun]

Because intelligence is adaptive.

Why didn't it happen to other animals?

 

[Mallon]

Why didn't it happen to other animals?

It did happen to other animals. Birds have bigger brains than their reptilian ancestors, for example. They just didn't develop them to the degree we developed ours. Evidently, they don't need to. They're doing fine as-is.

 

[juvenissun]

It did happen to other animals. Birds have bigger brains than their reptilian ancestors, for example. They just didn't develop them to the degree we developed ours. Evidently, they don't need to. They're doing fine as-is.

Does the cranial capacity of all animals (for those who have it) increase with time?

 

[philadiddle]

1. If the amount of samples (of different object) are not the same and all are plotted on the same diagram, then the the so-called "smooth curve" is simply deceptive.

From my experience with the statistic classes I've taken it would seem that there is no reason to say that the smooth curve is deceptive because of a variation in sample sizes. But it's not like I have a PhD in statistical analysis so if you can make a strong case for your point then please do so.

It would be dishonest to find a skull that's three million years old with a capacity of 1200ml and intentionally leave it off of the chart. Has that happened?

2. One of my question is: Are modern chimp skulls (many samples are available) also have higher S.D. in capacity? My guess is no. It would still have smaller S.D. than human skulls.

Ya, so?

3. My earlier (main) question is: why does the curve rise in value (cranial capacity)?

One explanation of this could be THE THEORY OF EVOLUTION.

The meaning of #3 is that if we could not answer this question, then the index of cranial capacity is basically meaningless. First, we do not know if the curve is true (#1). Second, we do not know how to interpret it.

The curve is true until we find fossils that fall on the chart contrary to the curve. This could potentially falsify the theory of evolution that I casually alluded to earlier.

So, according to my speculation, this curve should have an obvious kink somewhere close to the modern time. All fossils to the right (younger) side are human skulls and all others to the left (older) are chimp fossils. The appearance of human is sudden and should be clearly seen, rather than a smooth change, on the cranial capacity.

Where is this kink that you speculate should be there and why don't we see it?