Posted: Jun 24, 2014 8:07 am
Oldskeptic wrote:
Brain does attribute jaw bones at Swartkrans to leopards, but he is wrong. What they are is jaw bones of ancestors of leopards. Leopards had not evolved yet, and what left those jaw bones was no a more a leopard than the bones left by Australopithecus were human.
You don’t say where you get the information to contradict Dr Brain. The Wiki entry on leopards cite Uphyrkina et al(2001) to support the origin of modern leopard lineages 470000-825000 years ago. http://www.biosoil.ru/files/00001386.pdf
That study is based on worldwide genetic differences between living leopards assuming constant-rate genetic changes. The rate of change was calibrated from Turner and Anton (1997) report of leopard and lion fossils from Laetoli, 3.5ma. So it was adopted that lion and leopard lineages diverged at that date. From this calibration, the date of first divergence of living leopards was estimated to be up to 0.825 ma. Please note, Turner reported “leopard” not “ancestral leopard”. Indeed it’s quite tricky to declare some species as ancestral to another, it can easily turn out that that the branch point was earlier. There is no support for your claim that there were no leopards in the days of Australopithecus.
Oldskeptic wrote:
The tooth marks on the skull, if that's what they are and not just a coincidence, is not evidence that the cat killed the Australopithecus, at best it is evidence that the cat may have dragged a dead Australopithecus into the cave by the head. Did the cat kill or scavenge? We don't know.
Just coincidence? The match was a noteworthy discovery. It wasn’t achieved by a random computer search. Here’s the scenario. Bob notices dents on the Kranskop skull. My word thinks Bob. Could these be marks from a leopard’s teeth? He goes along the shelves containing 250 000 fossils from the Kranskop site till he finds the mandible. And gosh, it’s a perfect fit. Of course it could be coincidental, but it’s noteworthy and the ability to note is one of the things that has made Brain a scientist’s scientist; with honorary doctorates from four top universities in his country, in addition to his two professional doctorates.
Yes, it’s possible the Kranskop individual died from natural causes and the leopard just dragged it into the cave.
Oldskeptic wrote:
Saber-toothed cats most likely preyed on large slow herbivores, and were not well suited for catching smaller prey. This is where the evidence leads.
It’s almost incredible that you can say “That’s where the evidence leads” just after you have noted the possibility that the Kranskop leopard just dragged in a scavenged carcass. Well yes it’s also possible that the eagle that put its talons through the eyes of the Taung child had scavenged that.
There has been speculation that the sabretooth was a specialized hominin hunter, using its big teeth to make a quick kill and get away before the troop could concentrate. It may be though that once a habituated cat could get its teeth into a primate it could make a quick kill anyway. Boesch (1991) reports a leopard crushing a chimp’s rib cage
http://www.eva.mpg.de/primat/staff/boes ... dation.pdf
Even if the sabretooth was not an intentional hunter of australopiths it could have denied them foraging space the same way a Abram tank stops bickering between fighters armed with AK47s. It’s unlikely sabretooths were a negligible factor .
Oldskeptic wrote:
The ancestral hyenas of the time were not well suited for catching prey at all. With their strong heavy jaws they were very well suited to scavenge the carcasses of the large prey left behind by saber-toothed cats. This is where the evidence leads.
The evidence leading you seems to be the merest conventional knowledge of hyena. In this National geographic feature, http://ngm.nationalgeographic.com/ngm/0506/feature3/
hyenas are shown to be proficient hunters [i]Hyenas have an undeserved reputation as thieves and scavengers that subsist on the leavings of the larger predator. "But it is far more frequent that the lion will steal a kill from the hyenas," says Kay Holekamp of Michigan State University.
Oldskeptic wrote:
I'm making no assumptions here that Australopithecus wasn't prey to some predator or that it was. It could be either way or somewhere in the middle. We don't know.
Just as we don't know how much time Australopithecus might have spent in the trees or on the ground we don't know if any of the big cats of the time were adept at climbing trees.
You can’t discount Brain’s paleontological evidence that leopards lived with and probably preyed on the robust australopiths- or Paranthropus. Leopards are highly adept at tree climbing- as are felids generally, excepting ground-adapted lion and cheetah. Australopith feet were not adapted to grasping branches. We have tracks of them walking on the ground:
What we can know about the australopiths is that like all species in Africa they faced multiple predation threats and had a set of rules for responding to each. The degree of threat depended fluidly on circumstance; as with baboons, they could sometimes ignore a particular predator, in other circumstances it would prove fatal. They were under adaptive pressure to be able to forage in places as suited them, at times that suited them, in numbers that suited them, in all seasons and in all contexts of availability of alternative prey species.
Oldskeptic wrote:
How about admit that you don't have enough information to build a model. Never mind that there were no leopards at the time, and what saber-toothed cats there were preyed on large slow herbivores, and the ancestors of modern hyenas at the time had jaws suitable for bone crushing and scavenged what the saber-toothed cats left behind.
I’m not obliged to admit your jury-rig. Whether it’s a fossil australopith, T. rex or an algal mat, as soon as you see the fossil you can start to build a picture of its relation with its environment and it’s natural to do that. With the australopiths you start with a recognition that they lived in the larder of a cohort of proficient predators who had also alternative prey- and the alternative prey were proficient at avoiding predation. That’s the essential context and your blindness to it is astonishing, it requires an explanation. My explanation involves the influence of atheist ideology.
Oldskeptic wrote:
JayJay wrote:
There were leopards, and you are taking a simplistic view of hyena. In this study of predation on livestock in Tanzania Kissui(2008) “A total of 396 attack events were reported on cattle, goats/sheep, donkeys and dogs during the 19-month study period: 58% (n= 231) were by hyenas, 25% (n= 99) by lions and 17% (n= 66) by leopards.
http://www.cbs.umn.edu/sites/default/fi ... ersion.pdf
I'm just using what I've read about leopards and hyena ancestors, and not simplifying anything.
Tell me what modern African predators and livestock they kill and how they are killed as retaliation has anything to do with what is being discussed.
The modern context is a usable proxy for the African context a couple of million years ago. The link above demonstrates that hyenas are active predators, not just scavengers.
Oldskeptic wrote:
JayJay wrote:
The hidden contrary assumption you are making is the australopiths didn’t have any significant predators. Uniquely in their biome, they paid no forfeit in biomass to the top of the trophic pyramid, they could go anywhere at any time of their choice in any array as suited them without fear of predation. None of that is reasonable.
I didn't make any assumption. I said we don't know, and that is not an assumption.
You are doing a very interesting thing, which is choosing to not picture the australopiths at all, and calling that not making any assumption.
Oldskeptic wrote:JayJay wrote:
I certainly don’t admit that[that I simply don't know if they even used weapons]. It’s a strong inference that the australopiths used hand-held weapons against predation, maybe as strong as the inference originally made of T. rex, that it was a meat eater.
Of course you don't admit it because you want to make inferences and assumptions based on nothing but your wishful thinking.
Make up your mind. You say I admit, then that “of course” I don’t admit. Get it straight. I don’t admit
Oldskeptic wrote:
JayJay wrote:
From the inference one can predict that these weapons will be found, taphonomy permitting.
See, no weapons found, but you still want to assume that they were used.
Nope, no weapons found, just the fossil of the body that used the weapons. Just like, when the first T. rex was found, it was inferred from its body that it ate meat.
Oldskeptic wrote:
JayJay wrote:
The inference is drawn (again) from the australopiths eye teeth being unsuitable for tearing in conjunction with the use of the arms, from general primate use of biting, from lack of branch-grasping by their hind feet, their apparent lack of sprinting ability and from their descendant’s known use of hand weapons against predation.
Inference drawn from more baseless assumptions. Who says that australopiths couldn't climb trees or weren't fast sprinters? Some evidence suggests otherwise. That they were well suited for walking on tree branches and walking and running on land.
I’m sure australopiths could climb trees and did climb them to escape from some predators some of the time. And to get away from irritable buffalo etc. But their feet were not adapted, as tree-adept primates are, for grasping branches, which is useful for avoiding predation by adept climbing predators. Darwin recognised this difference by calling apes “quadrumana”.
The ostrich is a bipedal adept sprinter. Its high-mass muscles are at the top of its legs, with relatively thin, long lower legs. Quadruped antelope prey species that are good sprinters embody the same logic of lowered inertia in the lower limbs. Modern man, who has inherited the gross features of australopiths, is known to be a poor sprinter, see this extract from a table by
http://www.infoplease.com/ipa/A0004737.html
Cheetah70.00mph, Thomson's gazelle50.00, Wildebeest50.00, Cape hunting dog45.00, Hyena40.00, Ostrich40.00, Zebra40.00, Jackal35.00, Rabbit (domestic)35.00, Giraffe32.00, Cat (domestic)30.00, Wart hog30.00, Human27.89, Elephant25.00, Black mamba 20.00
Glad to hear we can outsprint an elephant and a mamba. Seems we can also outsprint a squirrel, chicken, house mouse, spider, three-tailed sloth and garden snail.
Oldskeptic wrote:
JayJay wrote:
It’s standard atheist operating procedure to reserve weapon use to a creature with “smarts”, as part of their origin myth of man-the-atheist. In doing that, atheists have managed to fuck up the history of human evolution, inverted it from the truth that our ancestors were led by the nose through the logical implications of creative relations between African species.
Which atheist said that it takes human intelligence to use a stick or a rock as a weapon? It wasn't me. And what is this atheist origin myth, did I miss a meeting? How have atheists fucked up the history of human evolution, by leaving God out of the process?
You said, á propos of australopiths supposedly not having had an optimized defensive weapon using :
And with a brain the same size a chimp you think that australopithecus had any more of a clue than chimps do today? You're projecting human like traits on a primate with a brain 1/3 the size of the human brain, a brain only 2/3 the size of homo habilis; the first rudimentary tool maker.
Your post illustrates this fuck-up . You consistently discount the ability of any predator to have acted on the australopiths. According to you hyena were mere scavengers, sabretooth too big and slow, leopard weren’t there at all. In this way you avoid discussing how other actors could have impacted on the morphology of human ancestors. Without such driving factors, the human origin narrative becomes an act on a stage as opposed to a process acting on a creature embedded in a set of relations. You claim it’s impossible to model the relationship between our ancestors and the biome they lived in. But it’s the relations between things in this biome that worked together in just such a way as to create the australopiths- and in turn Homo out of them. I say “create” because this process produced more out of less- a talking animal where a billion years earlier there had only been algal mats. You might agree with some of that in the abstract, but the actual narrative you dismiss is the one of embeddedness and intimate relations within a greater context.
Another aspect of the fuckup has to do with the role of role of mindfulness in the human origin narrative. You insist on associating tool making with the brainier Homo although we have been discussing the ecology of Australopiths, who according to Wiki, do appear to have chipped pebbles to make Oldowan tools. The essential element you aren’t admitting into the origin narrative is that of mindlessness - that our ancestors could have been mindlessly led by the nose along a creative path- No Clarke/Kubrik-style ape epiphany, no narrative of the intellectual awakening of Man.
Oldskeptic wrote:
What does this [the pom-pom crab] have to do with anything except you trying to refute something I didn't say?
You did say this: ”And with a brain the same size a chimp you think that australopithecus had any more of a clue than chimps do today? You're projecting human like traits on a primate with a brain 1/3 the size of the human brain, a brain only 2/3 the size of homo habilis; the first rudimentary tool maker.”
An animal doesn’t need a brain of any size to speak of, to optimize its use of a found object to defend itself. If chimps are clueless at it and australopiths were proficient, that had nothing to do with their brain size but with the particularities of their relationship with other creatures.
Oldskeptic wrote:
JayJay wrote:
There is a characteristic mean-spiritedness or selfishness behind this intent to pull every animal ability towards the present exalted humanity. Animals as simple as caddis worms use materials in well-chosen sophisticated ways, It’s absolutely endemic throughout nature, up to crows winkling food out of bottles using wires.
What the fuck are you talking about?
I was trying to identify an aspect of the character of the atheist origin narrative that has been constructed over the last decades.
Oldskeptic wrote:
JayJay wrote:
Come, take up my challenge to visualize a better body plan than Australopithcus, for applying simple hand-held weapons against predators.
No one is disputing that Australopithecus had hands capable of grasping sticks or stones or tree branches so I don't know what you're going on about.
Optimisation of a weapon-using defense would go further than just a hand-grip, it would work on the whole body. Picture the following non-optimal forms:
Picture a knuckle-walking ape having to carry a stick and a stone everywhere, in case it’s attacked while foraging. Compare that with a bipedal hominin, tucking a stick under its arm and holding the stone while walking.
Picture an ape confronting a leopard eye to eye, compared with a tall australopiths, ready to smash a stone down on the leopard’s skull.
Picture a ground-living ape, good at sprinting so with spindly shanks, confronting a hyena that darts around the side
Picture a curve-backed chimp smashing a stone onto a hyena’s skull, compared with a long-straight- backed australopiths doing that.
In a nutshell, what makes us better at tennis than a chimp is having inherited some of this optimisation.
Oldskeptic wrote:
Chimps on patrol groups don’t carry sticks and stones. What would happen if a hominoid species needed to do so while foraging? The great doors of logic would shift around them into a new of co-evolution with those sticks.
What are these great doors of logic shifting then? Were you talking about the sticks thinking logically?
Carrying a stick around and using it in a context that optimizes it’s quick and forceful use in a group defense of a primate troop, would dramatically change the constraints determining morphology. For example if the eye teeth are not used to rip chunks out of the predator that allows the teeth to lie in a plane and so the jaw can adapt to move sideways, grinding hard seeds.- as with Paranthropus. More portentously, a thinking head that doesn’t double as a war-head has different constraints. Socially a successful fighting defense allows for longer nurturing of young.
No the sticks don’t think logically.