Monthly Features
Faculty Profile: Mark Haussmann, Assistant professor of biology
In asking the question, "Why do we age?" Mark Haussmann has studied everything from saguaro cactus to Galapagos tortoises.
Avoiding predators leads to a longer life.
That might seem obvious, but Mark Haussmann, an assistant professor of biology, thinks the effect goes deeper than simply not becoming somebody's lunch.
In asking the question, "Why do we age?" Haussmann has studied everything from saguaro cactus to Galapagos tortoises, but he has focused on birds. Pound for pound, birds live much longer than most mammals, despite their small size and high metabolic rate. For example, small seabirds called Leach's storm-petrels can live almost 40 years. A mammal of the same size might be lucky to celebrate its first birthday.
Haussmann thinks flight might be the secret to birds' relatively long lives. Because birds can fly, they are better at escaping predators than is, for example, a mouse. A lower chance of being killed translates to a longer life, which in turn gives natural selection more time to act on any traits that counter the effects of aging.
For instance, flight requires a lot of energy and therefore a high metabolism – not usually a good thing in life span terms.
"We know that having a fast metabolism results in having more free radicals generated, which can cause oxidative damage," Haussmann said. "Currently, oxidative damage and free radical generation is thought to be the main determinant of aging. But despite having a high rate of oxygen consumption, birds produce fewer free radicals and have more antioxidant defenses, translating into lower levels of oxidative damage compared to terrestrial mammals."
Haussmann studies some of the mechanisms that birds have developed which result in their exceptional longevity, including elevated levels of antioxidant activity, DNA damage and repair, and telomere dynamics (telomeres are tips on the ends of DNA strands implicated in cell division and cancer). Haussmann and other biologists think that these traits have not evolved in species like mice, because mice are so limited by predation pressure. Chances are a mouse will be eaten before it could reap the benefits of any free-radical fighting mutation.
Haussmann takes a simple – and tasty – approach to bringing home the lessons of his research. He eats a healthy, well balanced diet full of foods high in antioxidants such as blueberries, strawberries, raspberries, red wine and, yes, a daily dose of dark chocolate.