Regulation of Heat and Energy Bioenergetics… flow of energy through an animal – determines the behavior, growth, and reproduction of an organism. Allocation of Energy – Energy obtained through hydrolysis of food is distributed according to the following needs production of ATP 1st biosynthesis for growth and repair second storage in the form of starch and fat third excess energy is released as thermal energy

Metabolic Rate Amount of energy used per unit time is the organism's metabolic rate – measured in 2 ways energy consumed compared to heat loss - measured with a calorimeter O2 consumed compared to the CO2 produced both require a closed system to measure cannot simply use calories consumed (fat 9Cal/g, carb 4 Cal/g, & protein 4Cal/g) due to the fact that excess calories are used for storage – Metabolic rate determines bioenergetic strategy birds and mammals have high metabolic needs which makes them endothermic – heat obtained from within fish and reptiles have low metabolic needs which makes them ectothermic – heat obtained from an outside source

Metabolic Rate – Metabolic rate and size are inversely related (in mammals) due to the need to regulate body temp and the larger surface area to volume relationship of smaller animals – Metabolic rate and activity are directly related basal metabolic rate (BMR) is the resting/non- stressed metabolic rate of an endotherm standard metabolic rate (SMR) is the resting /non-stressed metabolic rate of an ectotherm at a specific temperature the max metabolic rate is inversely related to the duration of activity – due to the debt that must be paid for the contribution of anaerobic respiration average daily metabolic rate is influenced by the time of day, sex, age, size, temperature (internal & external), food (quality and quantity), activity, O2 uptake, & hormone balance of an organism – most terrestrial animals have a average metabolic rate of times their BMR/SMR – Humans average is ~1.5 x BMR (unusually low)

Energy Budget compares the amount of energy needed by an organism to complete the tasks necessary for sustaining life and to reproduce – examples of categories are: BMR reproduction temp regulation growth activity costs

Homeostasis Regulation if the internal environment – managed through he interstitial fluid of an organism pH, blood sugar, & temp are the key components all must be maintained in a very narrow range regardless of the outside environment – strategies regulators - maintain internal environment regardless of the outside environment conformers - alter their internal environment with changes in the outside environment most organisms do a combination of both

Mechanisms of homeostasis - 3 functional components receptor - detects a change in the internal environment and sends a message to the control center control center - processes the information and relays a message to the effector effector - acts to change the condition 2 basic mechanisms – negative feedback positive response from the effector switches off the control center most mechanisms are like this as they prevent small changes from having an exaggerated effect on the organism – positive feedback positive response amplifies the action example: cervical pressure and strength of contractions in child birth under most circumstances the regulation on homeostasis in incompatible with a positive feedback loop