Carleton biology professor answers real world questions

The following story, written by Larisa Schieven, appears in the December, 2009 issue of Glebe Report.

Ottawa – Some of us may have wondered why we age. Answers vary from “inevitable wear and tear” to “making room for future generations.”Carleton Biology professor Dr. Tom Sherratt has recently come up with his own theory for aging which he suggests better explains the facts.

On December 9, Sherratt will be hosting a lecture at Carleton’s biweekly science café in the Glebe, organized by the Faculty of Science entitled “Why do we age?”

The lecture aims to explain a number of theories of aging, including Sherratt’s own. According to Sherratt, the idea for the research came primarily from wondering why his own body was gradually falling apart.

His arguments are described in his new book, Big Questions in Ecology and Evolution (Oxford University Press) which addresses a number of evolutionary and ecological questions such as “Why do we age?” and “Why are the tropics so diverse?”

Sherratt says that his theory of aging, conducted with postdoc Rob Laird, began with a growing suspicion that none of the most popular and commonly accepted theories are completely accurate. “It is easy to think that living organisms age for much the same reason that household appliances eventually break down -bad things happen and then you die,” says Sherratt, “but that’s not the real answer.”

Sherratt’s theory assumes that all organisms have evolved mechanisms to prevent and repair the chemical and physical damage that they receive during their lifetimes. However, some forms of mortality (e.g. death by accidents, or predators) are ultimately unavoidable, so the prevention and repair mechanisms that have evolved in organisms do not have to be perfect.

Instead, “they just need to be sufficient to keep the organism alive for long enough until the inevitable happens.” “Biologically speaking, a Reliant Robin engine in your car will be just as dependable as a Rolls Royce engine, if it has to go to the scrapyard after one year,” says Sherratt. “So, aging arises as a consequence of accumulated damage.”

In a nutshell, Sherratt argues that aging occurs because natural selection “does not care about the fate of old individuals.” “Aging is one of the most universal properties of living organisms, but on a personal level, it is nice to know why I haven’t evolved to last forever,” says Sherratt.

“Why do we age?” will take place on December 9, at the Wild Oat Café at 817 Bank Street, from 6:30-7:30 p.m. Seating is limited.

For more information on this and other science cafés, please visit http://www.carleton.ca/science/cafe/index.html.