Bio 316 Energy Metaboloism

Which molecule(s) is(are) generated during aerobic metabolism?

CO2 and H2O

large animals

Consume 1/3 body mass weekly

thermodynamics first law

Energy cannot be created or destroyed But it can be change •Chemical energy -> mechanical energy •mechanical energy -> kinetic energy (heat)

Specific Dynamic Action (SDA)

Increase in metabolic rate following food consumption

small animals

On a mass-specific basis, small animals require more food than larger animals. (Consume 6 x body mass weekly)

Thermodynamic principles

Physiological systems require energy inputs to maintain structural/functional organization Energy is necessary to create and maintain animals' essential internal organization

Metabolic rate

Rate of converting chemical or potential energy to cellular/organismal work and heat Rate of energy consumption (use)•units = calories or joules per unit time, or watts (1 cal =4.186J W=J/s

SDA

SDA reflects the added energy needed for digestion, absorption, and assimilation

Whole animal methabolic rate

Whole-animal metabolic rates do not increase linearly, because mass-specific metabolic rates decrease with increasing body mass

"high-grade" energy

chemical, electrical, mechanical enegy

Which of these animals has the lowest mass-specific metabolic rate

lizard

Suppose you discover the fossilized gill arches from a previously unknown species of fish. The gill arches have long, closely packed gill rakers. This fish most likely obtained its energy from

suspension feeding.

Factors that affect metabolic rate

•Activity level •Environmental temperature• Endotherms vs. ectotherms •Nutritive status: digestion and absorption require energy -Specific dynamic action (SDA)•Body size: whole-body and mass-specific relationships •Other: age, gender, time of day/season, etc.

Levels of metabolism

•Basal metabolic rate (BMR): Endotherms•Fasting and resting•Within thermoneutral zone •Standard metabolic rate (SMR): Ectotherms•Fasting and resting•At specified body temperature •Field metabolic rate (FMR)•Any conditions and activities of free-living animals in nature

Metabolic rate and body mass

•Larger animals have higher whole-body rates of metabolism than smaller animals. •Smaller animals have higher mass-specific rates of metabolism than larger animals. •Mitochondria per gram of tissue •Heart rate relative to body mass• The metabolic rate of endotherms exceeds that of ectotherms.