Posted: Jul 25, 2014 6:56 am
by Jayjay4547
Sendraks wrote:

I will respond to a few points though, just to further demonstrate the levels of ignorance on JayJay's part.

Well let’s see how you go then.
Sendraks wrote:
Jayjay4547 wrote:You don’t explain why the variety of predation threats the australopiths faced should be irrelevant.

Because density matters more than variety, when we're discussing the density of the predators most like to predate on australopiths to which your stick hypothesis applies.

I don’t like to call it a hypothesis, it’s an inference drawn from the morphology of the australopiths- including their eyeteeth but also their bipedalism arched feet and hands adapted to throw and club, plus the abilities of their sympatric predators, and alternative alternative prey and the skills of their descendants. The inference is that the australopiths defended themselves with objects they carried around continuously. It’s a staringly obvious inference that was actually drawn decades ago, but instantly diverted into the “hunting hypothesis” Now it has been airbrushed out though a focus on social behaviour of modern apes.

There is a strange attractor present when the human origin narrative is drawn and I call it atheist ideology. That ideology can be mapped by looking at the particular bias it has placed on the narrative.

As to your reply it’s unacceptably crude to to claim that variety of predator is irrelevant because “density matters more than variety” Both matter. For example to defend against a leopard at a roosting place at night, an australopith would need good night vision and good co-ordination of defenders. To defend against a pack of hunting dogs in the day they would need also endurance against being harried into exhaustion.

Sendraks wrote:
Unless you're going to give us all a good laugh by claiming a 1.4m high australopith is going to successfully deter a Lion with a stick, anymore than a juvenille impala would deter one?

I don’t know really, but two or three australopiths armed with sticks and stones might well have if they were good enough at it. And all African mammals are good at what they are adapted to do and presumably were so then. An adult primate of 30kg can be assumed to be a lot more dangerous than a juvenile impala if only because generally speaking, primates have an inclination to fight whereas impala are inclined to flee.

Sendraks wrote:
Jayjay4547 wrote:So here Myers doesn’t claim that the savannah has lower predator density than the forest which is what you claimed, just fewer leopards. The data suggests that the savanna has higher mammal predator biomass than the forest. (32.4 to 95.7 kg/km^2 in savannah, 30kg/km^2 in forest)

A few points here.
1) We are talking about Leopard predation of chimps here, which appears to be our best existing analogue to demonstrate the relationship between australopiths and leopards. So leopard density is key.

Leopard density is significant sure. But suppose it is low in the savanna, leopards still create a burden on savanna baboons in Botswana. Predation by leopards and lions is the primary cause of mortality among juvenile and adult baboons in the Okavango (Busse 1980; Cheney et al. 2004). Predators are known or suspected to be responsible for up to 96% of adult female deaths

it is also important whether a primate troop is specifically targeted by a particular habitual predator, as seems to have been the case for a while with Boesch’s chimps in the Tai forest. Judging by the Indian man eaters, such an animal might be 100 times more able to harvest biomass off the troop, besides dramatically inhibiting the troop’s foraging.

The presence of non-habituated predators –( possibly lions) can also restrict foraging. The simplest adequate factoring of predation stress on australopiths should include highly skilled habituated predator, (most likely leopard), large predators to whom they might have reacted by climbing trees (sabretooth s?) - and who could restrict foraging to areas with climbable trees- and smaller predators to whom they had to “often” prove their unsuitability as prey, and to whom they might have become vulnerable in times of stress.

Sendraks wrote:
2) The Ngorongoro Crater park is a singular environment and can not be consider an example of a.n.other savannah environment. I'll leave you to work out what that might be.

No Sendraks, I’ll leave you to work that out with Myers, who gave that figure as one limit of the range of predator biomass on the savanna, in his attempt to get some handle on possible predator biomass in the forest. I also used that value as a limiting one.

You claimed that when hominoids left the forest they entered a “low predator environment” That is complete balderdash as you really should have known. The predator biomass is at least as great in the savanna (as stands to reason from the mammal-edible savanna grass, that is the primary producer). The variety of savannah predators is higher and finally the visibility of prey on the savanna is higher, where sight, sound and smell carries further. I’ve raised these with you before, so far you have ignored it, instead you obdurately continued with the balderdash.

And the whole point of your “low predator environment” balderdash is to take the australopiths out of the trophic pyramid, out of their context embedded in necessities imposed by the African biomes. Well you aren’t alone in that.

Sendraks wrote:
3) The density of predators in the crater is in correlation to the density of prey. And that prey in the crater is predominantly not chimpanzeees.

So what. Three million years ago the crater was already there and doubtless the australopiths traipsed through it.

Sendraks wrote:
and finally.
4) Australopiths could climb trees. Almost certainly better than homo sapiens can.

That’s scarcely the issue, which is, could australopiths climb better than leopards? Because if they couldn’t (and they definitely couldn’t) , then a treed australopith would have been harvested by leopards like apples from a tree. Because australopiths didn’t have fangs to bite with. And they couldn’t climb while holding a stick or a stone or even fight effectively in a tree. And primates as a group don’t allow themselves to be harvested like apples, we are k strategists, our flesh is precious to us and expensive to access.