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ORIGINAL: eyesopened

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ORIGINAL: Rule

I agree (from a spiritual perspective) - but mammals surviving where dinosaurs became extinct doesn't have anything to do with the evolution of the sight pathway, does it?

As far as science is concerned, the mammals mostly surviving was coincidence, though.

Yes, survival is random.  I cannot stand to hear Evolutionists spout on about how the eye evolved or how an organism evolved to adapt to its environment like the oranisms had a meeting and said "we would be just so much cooler than the other orgaisms if we had an eye" and someone suggested hell let's grow two eyes!  There are successful mutations and unsuccesful ones.  The giraffe did not grow a long neck cuz it likes the leaves on the treetops, it eats the leaves because it has a long neck and there isn't any competion for that food source.  It lives in an area that suits its mutation and where the mutation is successful, it did not mutate to fit the environment it found itself in.  Damn Evoltionists can be as fucked up as the religions nuts, in my observation.

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ORIGINAL: eyesopened

The giraffe did not grow a long neck cuz it likes the leaves on the treetops, it eats the leaves because it has a long neck and there isn't any competion for that food source.

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ORIGINAL: NihilusZero

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ORIGINAL: eyesopened
The giraffe did not grow a long neck cuz it likes the leaves on the treetops, it eats the leaves because it has a long neck and there isn't any competion for that food source.

Actually, the males developed those sturdier necks to win over the mate when necking (giraffe-fighting), and the genes got passed on in that manner.

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ORIGINAL: Rule

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ORIGINAL: NihilusZero

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ORIGINAL: eyesopened
The giraffe did not grow a long neck cuz it likes the leaves on the treetops, it eats the leaves because it has a long neck and there isn't any competion for that food source.

Actually, the males developed those sturdier necks to win over the mate when necking (giraffe-fighting), and the genes got passed on in that manner.

You are both wrong. The animals on the African plains, including our ancestors, evolved because of one new and utterly cruel condition: heat! Without the shade provided by the trees that disappeared when the Great Rift Valley started to form, all animals in the area east of the Rift were exposed to the implacable tropical sun. It caused our ancestors to stand up, to evolve thin, short body hairs, to evolve curly hair on their skulls, to sweat, to evolve ever larger and ever deeper grooved brains. It also selected against giraffes with short necks: the shorter their necks, the earlier their brains boiled. It is HOT near the ground. The higher above the ground, the less hot it gets. (Presumably the long necks of some dinosaurs evolved for the same reason.)

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ORIGINAL: willbeurdaddy
In moist air as in the tropics the lapse rate (change in temperature for an increase in altitude) is about 1-2 degrees centigrade per thousand feet. Assuming a linear decrease its 3 hundreths of a degree at 20 feet. (Its probably less than linear because the closer to the ground the larger the effect of the earth's heat radiation, which I assume would follow an inverse square kind of rule.) that kind of change wouldnt do jack for "brain boiling" heat.

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ORIGINAL: Rule

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ORIGINAL: willbeurdaddy
In moist air as in the tropics the lapse rate (change in temperature for an increase in altitude) is about 1-2 degrees centigrade per thousand feet. Assuming a linear decrease its 3 hundreths of a degree at 20 feet. (Its probably less than linear because the closer to the ground the larger the effect of the earth's heat radiation, which I assume would follow an inverse square kind of rule.) that kind of change wouldnt do jack for "brain boiling" heat.

That is sufficient for natural selection to take hold and cause evolution at an ever increasing - exponential - rate.

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ORIGINAL: Rule

You are both wrong. The animals on the African plains, including our ancestors, evolved because of one new and utterly cruel condition: heat! Without the shade provided by the trees that disappeared when the Great Rift Valley started to form, all animals in the area east of the Rift were exposed to the implacable tropical sun. It caused our ancestors to stand up, to evolve thin, short body hairs, to evolve curly hair on their skulls, to sweat, to evolve ever larger and ever deeper grooved brains. It also selected against giraffes with short necks: the shorter their necks, the earlier their brains boiled. It is HOT near the ground. The higher above the ground, the less hot it gets. (Presumably the long necks of some dinosaurs evolved for the same reason.)

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ORIGINAL: Rule

That is sufficient for natural selection to take hold and cause evolution at an ever increasing - exponential - rate.

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ORIGINAL: NihilusZero
what physiological weakness do giraffes have that the remainder of the savanna creatures don't (leading to not having hyenas with stilts for legs or lions that shave their manes to cool off)?

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ORIGINAL: Rule

Show me a temperature graph of the first ten metres above the African plain.

As for our ancestor, it is simply the ratio of two dimensional, horizontal surface exposed to the sun versus total body (and brain) volume. (That might also apply to the neck of a giraffe? Yes.)

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ORIGINAL: NihilusZero
And also the reason that the zebras went extinc...wait...

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ORIGINAL: willbeurdaddy
Dont need a graph.

"The rapidity with which temperature decreases with altitude. The normal lapse rate is defined to be 3.6 degrees F per 1000 feet change in altitude. The dry adiabatic lapse rate is about 5.5 degrees F per 1000 feet, and the wet adiabatic lapse rate varies between 2 and 5 degrees F per 1000 feet."

Again, since the closer to the "heat sink" of earth, the hotter its likely to be, very little of the 2-5 degree/1000 wet lapse rate will be closer to the earth. Even giving it a linear change though means that at most 1 tenth of a degree change from ground to giraffe top.

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ORIGINAL: Rule

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ORIGINAL: NihilusZero
And also the reason that the zebras went extinc...wait...

I quote: "[Zebra] Brain temperature consistently exceeded blood temperature, on average by 0.2-0.4°C"

Zebra apparently transfer heat from their brain to their larger blood volume, I conclude. If so, I would expect them to evolve smaller brains, or larger bodies. (I have no idea is that reflects reality.)

I am now starting to wonder about the function of zebra stripes. It has always been assumed that its sole purpose is camouflage from predators, yet zebra are the only animals that camouflage themselves this way.

Can it be that the predominant function of the stripes is to cool the zebra? White areas reflect light and are relatively cold. Black areas absorb light and are very hot. Air will be heated by the black areas and rise. Cold air will fall down on the white areas, and be sucked onto the adjacent black areas, cooling them and then rising again. Thus the body of the zebra is cooled by circulating air. Neat. Paint zebra all white or all black and their brain will boil.

Eureka!

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ORIGINAL: willbeurdaddy
The difference in brain vs body temperature has nothing to do with height which was why you claimed giraffe necks and upright walking evovled.

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ORIGINAL: willbeurdaddy
Brain tissue metabolism creates more heat, and while selective brain cooling in other animals solves that problem, Zebras dont have a carotid rete to accomplish it. The primary reason why is because, at least in Zebras and other equids brain tissue is no more sensitive to heat than other tissue, and they employ other methods for cooling during hypothermia.

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ORIGINAL: willbeurdaddy
The idea of stripes for thermal control is nothing new, but it isnt due to any heat exchange mechanism that you theorize. The theory biologists maintain is related to the heat capacity of fat, and the stripes vary with the fat content underneath the skin,

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ORIGINAL: pyroaquatic
So what does this have to do with the definition of God?