Mystery solved. How and why human ancestors became upright.

[Gawdzilla Sama]

No, I don't think anything is selected for a purpose. They are selected, and that selection has a result. If that result helps eventual reproduction, the genes prosper in the population.
The idea of a purpose would be quite wrong.
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Superfluous period aside, you do realise you just shat over your own presumption with this comment?

I'm not going to attempt to untangle your silly riddles. But at least you speak your mind. Even when there's nothing in there.
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It's not a riddle, it's a simple statement of fact. You just refuted your OP. Congrats.

[mistermack]

I tried to make the OP as simple as possible. But I can't cater just for you two.






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[Gawdzilla Sama]

I tried to make the OP as simple as possible. But I can't cater just for you two.






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Ipso facto simple when you post.

[Trolldor]

I tried to make the OP as simple as possible. But I can't cater just for you two.






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Aye, I tend to like statements that stand on solid ground, have a basis on fact and rely on hard evidence.

You like to rely on "cause I say so".

[mistermack]

Aye, I tend to like statements that stand on solid ground, have a basis on fact and rely on hard evidence.

You're certainly a master of disguise then.
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[Trolldor]

Oh ho, was that an attempt at a witty comeback?

[Gawdzilla Sama]

Oh ho, was that an attempt at a witty comeback?

Half way, I think.

[GenesForLife]

Hox mutations can have remarkably dramatic, disproportionately large effects, again, point being?

[mistermack]

Hox mutations can have remarkably dramatic, disproportionately large effects, again, point being?

I'm not sure I'm with you there. I've never seen any claim by any scientist that bipedalism was the result of homeosis.
If you look at the many varied elements to bipedalism, the change in the entry position of the spine to the braincase, or the changes in the big toe, or the knees, or the pelvic region, it's pretty clear that it's a combination of things, not a unique mutation.
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[GenesForLife]

<facepalm>

Where did I say it was a single mutation?

[Gawdzilla Sama]

<facepalm>

Where did I say it was a single mutation?

Hey! No fair asking him to read the posts he's responding to.

[mistermack]

<facepalm>

Where did I say it was a single mutation?

I wasn't sure exactly what you were saying. But hox can produce big changes from a single mutation, I thought that's what you meant.
It wasn't very clear.

Here are some pictures of chimp canines, to illustrate what kind of weapons our ancestors used to have.

(Link)
(Link)
(Link)

Another sign of a change in fighting methods was the change in body size sexual dimorphism.
Males got more similar in size to females, in our species. .
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[GenesForLife]

The significance of the anatomical adaptations to upright posture and varying degrees of bipedalism seem among the hominoids has been a matter of ongoing interest [54], [55] [56]. Nonetheless, it has been widely accepted that specialization for full time primary bipedal locomotion did not occur in the direct human lineage until the split from chimpanzees had taken place about six million years ago.

However, when the various components of axial anatomical specialization in hominoids are fully identified, and their context in the broader setting of mammalian homeotic evolution is made clear, an alternate sequence of events becomes increasingly compelling. This is the possibility that a distinct and ancient clade within the hominoids can be identified that share a major modification of axial architecture that underlies the upright posture and primary bipedalism of modern humans. This morph appears to persist across the succeeding 21 million yeas to be preserved in primitive form in modern humans. The various other types of specialized locomotion seen among existing hominoids are made possible by comparatively minor secondary and tertiary modifications of the original primitive upright, bipedal architecture. This is the basis for asserting a homeotic transformation is the basis of the origin of humanity.

So, you've now officially seen a scientist attribute the origin of bipedalism to homeosis, nowhere does the author of the paper or do I insist it was a single one.

From the Results & Discussions, I quote...

This study revealed that body configuration modification in the Mammalia often involves emergence and change of homeotic gradients. In a number of instances clusters of multiple different homeotic gradient changes occurred at the stem of a major systematic radiation (Figure 1).

These clusters of homeotic change generally qualify as body plan changes and often relate to significant alterations in the adaptive zone of the descendant groups. These clusters of changes are often preserved as a fixed homeotic set in the descendant group across tens of millions or hundreds of millions of years.

Within individual lineages many of the gradients demonstrate alterations on a sporadic basis (at the level of species or higher level clades). Some lineages (e.g. hominiform hominoids, pilosan xenarthrans) show a very high frequency of homeotic change for some gradients. Other lineages show little or no homeotic change over hundreds of millions of years (Monotremata).

Some homeotic alterations appear to be relatively highly conserved–they fluctuate in their expression among more ancient lineages but eventually become fixed (e.g. lumbar rib suppression). A few homeotic features never change after their initial appearance (e.g. emergence of the laminapophyis, septo-neural approximation).

For more information read the rest of the paper, wherein they discuss the various anatomical features central to bipedalism and human anatomy and how they may have evolved with homeotic gradient changes in context.

The paper is here, by the way. http://www.plosone.org/article/info%3Ad ... ne.0001019

[Gawdzilla Sama]

Here are some pictures of chimp canines, to illustrate what kind of weapons our ancestors used to have.

(Link)
(Link)
(Link)

Why don't you post pictures of what our ancestors actually had instead of what chimps have now?

@Genes, spoiler that fucker, please?

[GenesForLife]

Hox mutations can have drastic morphogenetic impact =/= a single mutation in a hox gene caused the human body plan to be bipedal.