Why do Individuals Differ in their Metabolic Rate?

Date: Monday 8^th August 2016

Time: 7pm

Venue: the Victorian Bar, Tron Theatre

Speaker: Neil Metcalfe

The term ‘metabolism’ is in common usage, but what does it actually mean? In fact there are many different definitions of metabolism and metabolic rate, but all relate to the way in which the body uses food to create the energy needed for fuel its chemical processes. We usually measure metabolic rate by recording the rate at which oxygen is consumed or carbon dioxide produced. Metabolic rate varies over time, from a minimal (basal) level when inactive to a maximal level when the body is working at its hardest (for instance through combinations of physical activity, growing fast, digesting big meals, and even breast feeding). However, in all cases it is notable that individuals vary in their metabolic rate even under the same conditions – a phenomenon that has been found right across the animal kingdom.

Why should this be? Why should some individuals use up far more food and oxygen than others when doing the same task? What are the consequences? Why has evolution and natural selection not led to all individuals having the same ‘optimal’ metabolic rate? This discussion will use examples from other animals as well as humans to explore the reasons for this variation in metabolism, and will show how metabolic rate is linked to many other traits such as aggressiveness, digestion rate and even the rate of ageing.

About the speaker:

Professor Neil Metcalfe is a behavioural and physiological ecologist at the University of Glasgow. His research focuses on variation among individuals, in particular understanding how small behavioural or physiological differences in early life can have major lifelong effects. Much of this work has been done on fish (especially salmon and trout), although he has also worked on birds and mammals. He is a Fellow of the Royal Society of Edinburgh and a Member of the Academia Europaea.