Posted on 11/19/2002 12:54:45 PM PST by PatrickHenry
We humans are strange primates. We walk on two legs, carry around enormous brains and have colonized every corner of the globe. Anthropologists and biologists have long sought to understand how our lineage came to differ so profoundly from the primate norm in these ways, and over the years all manner of hypotheses aimed at explaining each of these oddities have been put forth. But a growing body of evidence indicates that these miscellaneous quirks of humanity in fact have a common thread: they are largely the result of natural selection acting to maximize dietary quality and foraging efficiency. Changes in food availability over time, it seems, strongly influenced our hominid ancestors. Thus, in an evolutionary sense, we are very much what we ate.
Accordingly, what we eat is yet another way in which we differ from our primate kin. Contemporary human populations the world over have diets richer in calories and nutrients than those of our cousins, the great apes. So when and how did our ancestors' eating habits diverge from those of other primates? Further, to what extent have modern humans departed from the ancestral dietary pattern?
Scientific interest in the evolution of human nutritional requirements has a long history. But relevant investigations started gaining momentum after 1985, when S. Boyd Eaton and Melvin J. Konner of Emory University published a seminal paper in the New England Journal of Medicine entitled "Paleolithic Nutrition." They argued that the prevalence in modern societies of many chronic diseases--obesity, hypertension, coronary heart disease and diabetes, among them--is the consequence of a mismatch between modern dietary patterns and the type of diet that our species evolved to eat as prehistoric hunter-gatherers. Since then, however, understanding of the evolution of human nutritional needs has advanced considerably-- thanks in large part to new comparative analyses of traditionally living human populations and other primates--and a more nuanced picture has emerged. We now know that humans have evolved not to subsist on a single, Paleolithic diet but to be flexible eaters, an insight that has important implications for the current debate over what people today should eat in order to be healthy.
To appreciate the role of diet in human evolution, we must remember that the search for food, its consumption and, ultimately, how it is used for biological processes are all critical aspects of an organism's ecology. The energy dynamic between organisms and their environments--that is, energy expended in relation to energy acquired--has important adaptive consequences for survival and reproduction. These two components of Darwinian fitness are reflected in the way we divide up an animal's energy budget. Maintenance energy is what keeps an animal alive on a day-to-day basis. Productive energy, on the other hand, is associated with producing and raising offspring for the next generation. For mammals like ourselves, this must cover the increased costs that mothers incur during pregnancy and lactation.
The type of environment a creature inhabits will influence the distribution of energy between these components, with harsher conditions creating higher maintenance demands. Nevertheless, the goal of all organisms is the same: to devote sufficient funds to reproduction to ensure the long-term success of the species. Thus, by looking at the way animals go about obtaining and then allocating food energy, we can better discern how natural selection produces evolutionary change.
Becoming Bipeds
Without exception, living nonhuman primates habitually move around on all fours, or quadrupedally, when they are on the ground. Scientists generally assume therefore that the last common ancestor of humans and chimpanzees (our closest living relative) was also a quadruped. Exactly when the last common ancestor lived is unknown, but clear indications of bipedalism--the trait that distinguished ancient humans from other apes--are evident in the oldest known species of Australopithecus, which lived in Africa roughly four million years ago. Ideas about why bipedalism evolved abound in the paleoanthropological literature. C. Owen Lovejoy of Kent State University proposed in 1981 that two-legged locomotion freed the arms to carry children and foraged goods. More recently, Kevin D. Hunt of Indiana University has posited that bipedalism emerged as a feeding posture that enabled access to foods that had previously been out of reach. Peter Wheeler of Liverpool John Moores University submits that moving upright allowed early humans to better regulate their body temperature by exposing less surface area to the blazing African sun.
[Long article. Click here for the Next 5 Pages.
(Excerpt) Read more at sciam.com ...
Round Hole? (Reality)
Solution? Bigger Hammer!!! (Creative 'Science')
It's all interrelated. A predator pack needs a large territory, and needs to defend that territory against competitors. Those who are best at utilizing their territory, and in defending it and expanding it, will pass on their genes. Those who are ineffective in defending their territory from encroachment will die out. Somehow, I think there's some applicability here with regards to our current immigration policy...
Or lack of therein..... :)
Like when we were cast out of eden and childbirth would henceforth be painful due to larger crania?
There are so many allusions to evolution in the Adam/Eve scenario.... but pondering them sure starts a lot of fights around here.
When I consider Desmond Morris' The Naked Ape within the context of Genesis, it sure explains a lot. I think he stretches a bit at times, but he's spot on when he restricts himself to zoological interpretation of human evolution.
Then it was noticed that almost the same process made bread. So mankind built cities to provide infrastructure for beer and bread-making. That's about as far as we have gotten so far.
"The problem is that medical science is preventing that step in human evolution. If they keep on doing heart bypass operations to save people, then the genetic superiority of those who can survive "Super Sizing" their fast food meals cannot be exploited. However, if Hitlery takes over the country's medical system and drives it into the ground, people will no longer be able to survive their heart attacks."
Evolution continues as always...and may have even acellerated(sp).
My theory:
If, as has been claimed, that our bodies are now contaminated with drugs, alcohol, nicotine, fats and etc., the sperm and eggs of future humans that cannot cope with these 'pollutants' very simply do not conceive. Females have many unknown abortions through-out their lives and all the 'problems' of modern society are comprehended in this process. Only those that can tolerate present day conditions even make it to being conceived. The high cholestoral and heart attacks are just a minor player in this scenario.
Thus arose the French... :-)
Patrick, say it with some feeling, like:
Wow! Another crevo-thread!!!
Hehe
I've seen more enthusiasm at a Walter Mondale victory party. I guess some threads just don't catch fire. Whatcha gonna do?
Study explores plausibility of bulbs and tubers in the diet of early human ancestors
PhysOrg | Friday, July 25, 2008 | UC Santa Cruz
Posted on 07/25/2008 8:15:37 PM PDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/2051557/posts
|
|
|||
Gods |
Blast from the Past. |
||
|
· Mirabilis · Texas AM Anthropology News · Yahoo Anthro & Archaeo · · History or Science & Nature Podcasts · Excerpt, or Link only? · cgk's list of ping lists · |
|||
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.