The Stress of Cold Temperatures Extends Lifespans

In 1986, John Holloszy of Washington University immersed his lab rats in shallow, cool water for four hours each day. They burned so many extra calories that they ate half again as much as control rats, but weighed less. The cold rats lived 10% longer, on average. Holloszy framed his report on this experiment not as a hormetic effect of cold exposure, but as a refutation of the “rate of living” hypothesis. In 2006, Gordon Lithgow of the Buck Institute for Aging Research exposed lab worms...

 Humans are Like Deer in the Anthropocene

I asked Rooney about the remarkable ability of deer to thrive in their home range—most of the U.S.—while producing ecosystem simplification and a biodiversity crash. In his own studies of deer habitats in Wisconsin, Rooney found that only a few types of grass thrive under a deer-dominant regime. The rest, amounting to around 80 percent of native Wisconsin plant species, had been eradicated. “The 80 percent represent the disappearance of 300 million years of evolutionary history,” he s...

 The HANDY Model is Based On Predator-Prey Cycles

As indicated above, Human And Nature DYnamics (HANDY) was originally built based on the predator-prey model. We can think of the human population as the predator", while nature (the natural resources of the surrounding environment) can be taken as the prey", depleted by humans. In animal models, carrying capacity is an upper ceiling on long-term population. When the population surpasses the carrying capacity, mechanisms such as starvation or migration bring the population back down. However, ...