Of Chimps and Men

We share 98 percent of our genes. So how come
humans live twice as long as chimpanzees do?

HUMANS HAVE EVOLVED two traits that sharply differ from their great ape relatives and appear to be antagonistic: slower aging despite a major increase in meat eating. Chimpanzees live on average 30 years (and never more than 60), while humans average 80 years (one rare exception has reached 122). Why? Meat eating is not the norm for anthropoid primates. For 25 million years hominids have been mainly vegetarians. However, early man (and to a lesser degree early chimps) began hunting for meat a few million years ago.
One would expect the increase in cholesterol and dietary fat – known factors in the cell-deterioration of aging – to shorten life span. And in chimpanzees, it does; but not in man. A new study by Caleb Finch and USC primatologist Craig Stanford hypothesizes that the evolution of meat-adaptive genes (genes that somehow reduce the risks of high cholesterol, vascular disease and Alzheimer’s disease) in human ancestors accounts for our triple-digit potential life span.

Source: “Lipoprotein Genes and Diet in the Evolution of Human Intelligence and Longevity,” by Caleb E. Finch and Craig Stanford, in Brain and Longevity, IPSEN Foundation, 2002.


All That You Can Bee

There's no better proof that “you are what you eat” than the mysterious life of the honey bee.

BEES PROVIDE a wonderful example of how the same set of genetic factors can yield dramatically different lifestyles and life spans. A queen honey bee will fly only once, on her famous nuptial flight, during which she will mate and acquire enough sperm to last her lifetime – about five years. Worker bees, by contrast, will fly miles a day as adults, quickly wearing themselves out and dying. Interestingly, honey bees from the same batch of fertilized eggs can grow up to become either long-lived queens or short-lived workers. It all depends on the amount and type of food provided by nurse bees. A larva destined to become a queen gets large meals that stimulate the secretion of juvenile hormone. If this hormone is not present at a critical time in development, the larva’s ovaries degenerate and the bee develops into a sterile worker. If this worker hatches in the early summer, it will live only two months. But if it happens to hatch later, it will stay with the queen over the winter, thereby increasing its life span five-fold.

Source: Aging, A Natural History, by Robert E. Ricklefs and Caleb E. Finch.


 Illustrated by Jason Lee
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