BIO 203.11 Lecture 4s(1)

BIO 203.11 Lecture 4s(1) - BIO 203: Lecture 4 - Temperature...

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1 BIO 203: Lecture 4 - Temperature Regulation Prof. William Collins Office: 534 Life Sciences Building Office Hours: Tuesdays, 11:30 AM - 12:30 PM Thursdays, 4:00 - 5:00 PM Ectotherms Endotherms Regulate T Body Change Physiology (e.g., vasoconstrict) Behaviorally Thermoregulate Insulation Metabolic Rate
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2 Relation Between Metabolic Rate (MR) and Ambient Temperature (T amb ) in Ectotherms MR T amb MR varies with T amb because T B T amb in ectotherms. At low T amb , MR is lower • use less energy • slower (easy prey!) At high T amb , MR is higher • use more energy • faster (better predator) Optimum MR Optimum T Relation Between T B and T amb for Endotherms T B 0 o C 40 o C T amb 37 o C Endotherm T B T B > T amb T B < T amb difference between T B and T amb Potential heat loss to environment Potential heat gain from environment
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3 Relation between MR and T amb in Endoterms T B 37 o T amb MR BMR hyperthermia hypothermia As T amb gets colder, MR increases to produce heat and maintain T B . Thermoneutral Zone (TZ) Basal metabolic rate Sweating requires energy Heat gain by metabolism equal and opposite to heat loss to environment. T B 37 o T amb MR BMR TZ 5 o Heat loss to environment Is equal to Heat gain due to increased MR
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Relationship Between Metabolic Rate (MR) and Ambient Temperature (T amb ) Ectotherms Endotherms T amb MR BMR TZ T B constant As T amb decreases: • T B decreases • MR decreases As T amb decreases: • MR increases to maintain T B T amb MR T B T amb Optimum MR Advantages of being an Ectotherm Need less energy More suited to variations in food supply Can tolerate a less predictable environment Can exploit a broader range of body sizes 80-90% of mammal species are less than 20 gms Length to diameter has higher variability freedom from heat-conserving constraints More efficient in producing biomass ingested food producing biomass not defending high T B . Advantages of being an Endotherm
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This note was uploaded on 02/21/2011 for the course BIO 203 taught by Professor Johncabot during the Spring '08 term at SUNY Stony Brook.

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BIO 203.11 Lecture 4s(1) - BIO 203: Lecture 4 - Temperature...

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