Posted on 12/09/2004 10:44:58 AM PST by Helms
- 03-22-2004, 07:40 PM
By Gilien Silsby and Gia Scafidi
When our human ancestors started eating meat, evolution served up a healthy bonus - the development of genes that offset high cholesterol and chronic diseases associated with a meat-rich diet, according to a new USC study. Those ancestors also started living longer than ever before - an unexpected evolutionary twist.
The research by USC professors Caleb Finch and Craig Stanford appeared in the Quarterly Review of Biology.
"At some point - probably about 2 1/2 million years ago - meat eating became important to humans," said Stanford, chair of the anthropology department in the USC College of Letters, Arts and Sciences, "and when that happened, everything changed."
"Meat contains cholesterol and fat, not to mention potential parasites and diseases like Mad Cow," he said. "We believe humans evolved to resist these kinds of things. Mad Cow disease - which probably goes back millions of years - would have wiped out the species if we hadn't developed meat-tolerant genes."
Finch, the paper's lead author, and Stanford found unexpected treasure troves in research ranging from chronic disease in great apes to the evolution of the human diet. They also focused on several genes, including apolipoprotein E (apoE), which decreases the risk of Alzheimer's and vascular disease in aging human adults.
Chimpanzees - which eat more meat than any other great ape, but are still largely vegetarian - served as an ideal comparison because they carry a different variation of the apoE gene, yet lack human ancestors' resistance to diseases associated with a meat-rich diet.
While chimpanzees have a shorter life span compared to humans, they demonstrate accelerated physical and cerebral development, remain fertile into old age and experience few brain-aging changes relative to the devastation of Alzheimer's seen in humans today. Finch and Stanford argued that the new human apoE variants protected the chimpanzees.
In a series of "evolutionary tradeoffs," the researchers said, humans lost some advantages over those primates, but gained a higher tolerance to meat, slower aging and longer lifespan.
Still, if humans developed genes to compensate for a meat-rich diet, why do so many now suffer from high cholesterol and vascular disease?
The answer is a lack of exercise and moderation, according to the researchers.
"This shift to a diet rich in meat and fat occurred at a time when the population was dominated by hunters and gatherers," said Finch, a USC University Professor and holder of the ARCO-William F. Kieschnick Chair in the Neurobiology of Aging.
"The level of physical activity among these human ancestors was much higher than most of us have ever known," he said. "Whether humans today, with our sedentary lifestyle, remain highly tolerant to meat eating remains an open question researchers are looking into."
Stanford, co-director of the university's Goodall Research Center, said that modern-day humans "tend to gorge ourselves with meat and fat."
"For example, our ancestors only ate bird eggs in the spring when they were available," he said. "Now we eat them year-round. They may have hunted one deer a season and eaten it over several months. We can go to the supermarket and buy as much meat as we want."
"I think we can learn a lesson from this," Stanford said. "Eating meat is fine, but in moderation and with a lot of exercise."
No, it wasn't that. Actually mushrooms and fungus do not belong to Kingdom Animal or Plantae. They are Kingdom Fungi, and they feed directly on dead materials.
Plants only feed on what the fungi leave behind in the ground.
What do vegetarians think about that ? Is it edible or not ? Especially considering that fungus is actually some of the most efficient lifeforms around as far as converting food to body mass metabolisms.
To be honest I am a complete omnivore with a preference for meat; I am rather curious as to what drives some people to eat vegan though. Personally I have never felt that much compassion for anything dead on my plate other than to hope it died cleanly.
I'm convinced that veganism is unhealthy. Every one I've met has had some kind of health problem, which they have to deal with through some sort of supplement, which means there was something wrong with their diet in the first place. Fruitarians are the freakiest, though. Like, WTH? The next step is to follow the Vulcan example, and just eat one-celled organisms? And the next step after that...to hang upside down on tree limbs for the rest of one's life. But I digress...
I'm not kidding when I say that the kid didn't have hair until he was 5 years old!
I saw it here on the Free Republic..."If God didn't want us to eat animals, He wouldn't have made them out of meat!"
Crab Eating Macaques
Diet: Crab eating macaques have the habit of inserting their hand in small burrows or holes to find crabs or other animals. In the mangrove swamp they have learned to feed on crabs, crustaceans, shellfish and other small animals exposed by the low tide.
That explains our use for K-9s and our apparent build for sucking the marrow out of bones. How does this explain a habit of red meats?
"...red meat..."
I would suspect that red meat eating would be a later development of a more "cultural" type than physical that an already meat digesting, longer living, and intelligent primate would turn to.
The creature that can eat fish that wash up or are grabbed from tidal pools has a wider food selection than the one who can just eat shellfish and are therefor less susceptible to food shortages and competition. The ones capable of properly digesting the fatty fish have even less competition and a wider range of places to live. One of them finds a crippled mouse and gives it a try. Soon its offspring are moving inland to "hunt" by intentionally reach into rodent dens the same way previous generations reached into crab holes. The progression of food sources, habitats, and intelligence levels just continue but the critical meat eating and fat digesting ability of this proto-humanoid is already present from earlier forms.
FTR. Lest some reader think Im trying to pass myself off as some sort of paleoanthropologist, Im not, nor did I sleep in a particular hotel last night, Im just trying to use logical commoners SWAG.
"I suppose it could. You can see here that our canines are rather atrophied compared to our existing more vegetarian primate relatives so Im not so sure theres a connection to meat eating with the canines."
The connection with canines and meat eating is that if you eat meat... you normally use canines. They cut and pierce the meat, making it easy to swallow and digest. Primates with an apparent canine set are going to be hunting and using those teeth as hunting weapons. Yes, some use tools, but there is a trend (IMHO) that the more ingenuitive the primate is, the smaller their teeth are.
This would suggest that intellect (and the evolution thereof) would compensate for a lack of natural tools. Either that, or we were built this way for simplicity's sake.
The idea of red meats being a "cultural" type over a "physical" one overestimates human nature. If I knew there was a rabbit in a bush, and saw a deer 20 paces off as well, I would try to take down the deer first. This isn't to say "look at me, I can eat red meat" this is to say "I can provide enough food for a while now. Thank goodness." It would be a need more than a development of culture. More meat for a social creature insures survival of the group, and thus the individual.
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