In “Are we meat eaters or vegetarians? Part II” (21. September 2009, 22:32 Uhr), Dr. Michael Eades says:
In April 1995 an article appeared in the journal Current Anthropology that was an intellectual tour de force and, in my view, an example of a perfect theoretical paper. “The Expensive-Tissue Hypothesis” (ETH) by Leslie Aiello and Peter Wheeler demonstrated by a brilliant thought experiment that our species didn’t evolve to eat meat but evolved because it ate meat.
In keeping with a great scientific tradition, Aiello and Wheeler were able to see what they saw because they stood on the shoulders of giants who came before them. In their case the giant was Max Kleiber, an animal physiologist working at the University of California at Davis, who published a groundbreaking paper in 1947 and a scholarly text titled The Fire of Life in 1961. Kleiber’s work involved the meticulous measurement of the metabolic rates of numerous animals, including humans. As he plotted the various metabolic rates, he discovered an extremely strong correlation between the mass of an animal and its metabolic rate. Kleiber found that this relationship held constant across numerous species. His October 1947 paper in Physiological Reviews simply titled “Body Size and Metabolic Rate” was a classic. By using the equations Kleiber worked out, the metabolic rate of virtually any animal could be determined simply by knowing the animal’s body size.
Since all animals measured have conformed to Kleiber’s law, Aiello and Wheeler postulated that animals now extinct – including our human and pre-human predecessors – would have fallen along the same line. Using skeletal remains paleontologists have been able to calculate body sizes of extinct animals along with pre-Homo and early-Homo species. Then using Kleiber’s law, it is possible to closely estimate the metabolic rates of these creatures. And here’s where it gets interesting.
According to Kleiber’s law, an australopithecine weighing 80 pounds would have the same metabolic rate as a human weighing 80 pounds despite the disparity in brain size between the two. The much larger brain of the human would have 4-5 times the metabolic rate of the brain of the australopithecine, yet would have the same overall metabolic rate. What gives?
The Blog of Michael R. Eades, M.D. © mreades 2009
Read Dr. Eades’ article to find out the answer! And more! It is a fascinating article.
Some of the development and hierarchy of science is made clear in it. But to see where it all came from, we’d have to trace this back to the work to study human metabolism in the first place, to Joule’s work in the mechanical equivalent of heat, to Mayer’s work in the conservation of energy principle, to Harvey applying mathematics to biology. And to the development of the math that made the knowledge possible in the first place.