|Feature Article - October 2013|
|by Do-While Jones|
The fight over diet-driven evolution
According to evolutionists, changes in diet caused the evolutionary split between apes and humans. In particular, it is now believed (by some) that eating grasses caused humans to evolve from their apelike ancestors.
The traditional story about how apes evolved to humans is nearly 90 years old.
Humans, like children, are the products of their environment. The famous anatomist Raymond Dart recognized that back in 1925, when he described the first hominin skull found in Africa. The evolution of this "Man-Ape," he wrote, markedly differed from that of earlier apes. While apes lolled about in "luxuriant" tropical forests that posed relatively few survival challenges, the "Man-Ape" had to compete for scarce food and water with saber-tooth tigers and other dangerous beasts of the arid savanna—and ended up sapient. "For the production of man a different apprenticeship was needed to sharpen the wits and quicken the higher manifestations of intellect—a more open veldt country," Dart wrote.
This "savanna hypothesis" suggested that as a drier climate caused grasslands to spread, our ancestors moved out of the trees and began walking upright in order to spot predators and prey in the waist-high stems. That freed their hands to use tools and spurred the development of big brains.
Today, no serious paleoanthropologist believes that particular evolutionary tale. 1
New research, however, is reviving that old tale. Scientists have been taking core samples from places they believe to be habitats of ancient hominins, and measured the carbon isotopes in the remains of grasses found at various depths. Based on these carbon isotopes they classify the plants as “C3” or “C4.” Using assumptions about how these carbon isotopes relate to time, climate, and vegetation, they conclude,
As went plants, so went the animals that grazed on them: By 6 million years ago, C4 grasses had replaced C3 plants as the most significant component in the diet of African grazers, Cerling says, according to studies of carbon isotopes in the tooth enamel of horses, elephants, antelopes, and other animals.
This suggests that hominins were born when grasses were on the rise. In fact, Cerling and his colleagues think that the first hominins had more grass in their environment than initially proposed—40% to 60% of the vegetation at nine Ar. ramidus fossil sites was C4 plants, Cerling suggests (Science, 28 May 2010, p. 1105).
Recent data now show that later hominins responded to the rise of grasses by broadening their diets. Species that arose more than 4 million years ago, including Ar. ramidus and the oldest australopithecine, Australopithecus anamensis, subsisted on an apelike diet of at least 90% leaves and fruits from C3 plants, Cerling and his colleagues reported in June in the Proceedings of the National Academy of Sciences. By 3.5 million years ago, a descendant of Au. anamensis—Au. afarensis, whose most famous member is the skeleton named Lucy—apparently adapted to the widespread grasslands by also munching on many C4 plants, according to Cerling's analysis of carbon isotopes in the tooth enamel of seven hominin species. Au. afarensis—a leading candidate for the ancestor of Homo—and another hominin, Kenyanthropus platyops, still ate mostly C3 woodland plants, but about 22% of their diet was also made up of these C4 plants, making them the hominins with the most varied menu. Their meals included grasses and sedges such as water chestnuts and papyrus and perhaps animals that fed on those plants. 2
In other words, a variety of vegetables made us human.
So, 3.5 million years ago, eating vegetables made us human. But, 1.8 million years ago, eating meat made us human—at least that’s what evolutionists tell us.
Nearly two million years ago our ancestors began to barbecue. And those hot meals, Richard Wrangham argues, are what made us human.
With our supersized brains and shrunken teeth and guts, we humans are bizarre primates. Richard Wrangham of Harvard University has long argued that these and other peculiar traits of our kind arose as humans turned to cooking to improve food quality—making it softer and easier to digest and thus a richer source of energy. Humans, unlike any other animal, cannot survive on raw food in the wild, he observes. “We need to have our food cooked.”
Based on the anatomy of our fossil forebears, Wrangham thinks that Homo erectus had mastered cooking with fire by 1.8 million years ago. 3
But the article isn’t really about evolution. Wrangham’s conclusion is,
If you just say, “Well, animals eat their food raw, and humans are animals, then it should be fine for us to eat our food raw,” and you bring your children up this way, you’re putting them at very serious risk. 4
There is an ulterior motive for the article. He is using the “scientific” proof that eating cooked meat caused apes to evolve smarter brains in order to frighten vegetarians into feeding meat to their children by warning them about the “very serious risk” of eating raw, unprocessed foods.
Here’s how to tell real science from pseudo-science. Real science isn’t affected by personal belief. That is, a spark will cause hydrogen and oxygen to explode regardless of whether or not the scientist thinks it should. Science is based on experimental verification.
Pseudo-science is based on wishful thinking and is supported by rhetoric and politically biased interpretation of data.
Some scientists say eating a variety of raw grasses stimulated brain growth. Other scientists say eating cooked meat stimulated brain growth. Neither group has any experimental proof that they are right. It is all speculation, camouflaged by data interpreted by biased assumptions.
If evolution really was responsible for the origin of all the different forms of life, there would not be so many different, contradictory scenarios for how it must have happened.
When pointing out these contradictions, evolutionists usually retreat to an argument like this one: “Well, scientists may disagree on the details of whether it was eating meat, or eating grass, that caused man to evolve—but all scientists agree that diet caused man to evolve, so it must be true. The details don’t really matter—it’s the general principle that is important.”
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Ann Gibbons, Science, 2 August 2013, “How a Fickle Climate Made Us Human”, http://www.sciencemag.org/content/341/6145/474.full?sid=4f9e8fd3-dcc3-4294-8d27-ca23161a4f5a
3 Kate Wong, Scientific American, September 2013, pages 66-69, http://www.scientificamerican.com/article.cfm?id=case-for-very-early-cooking-heats-up