Thermoregulation and Osmoregulation
Temperature Regulation
Costs and Benefits
Balancing heat loss and gain
Related to Environment
Extreme Temperatures
Related to Organism
Ectotherms: fluctuate depending on environment temperature
Endotherms: internal regulation
Homeotherms: body temperature relatively stable regardless of environment (organism can be endo or ectothermic)
Poikilotherms: body temperature varies with environment (organism can be endo or ectothermic)
Ectotherms
Endotherms
Enzymes optimized for near constant internal conditions
remain active in spite of poor environmental conditions (benefit)
Optimized enzymes always run at high efficiency
Expend a lot of energy to maintain internal temp (cost)
Enzymes function under a range of internal conditions
Inactive under poor environmental conditions (cost)
Costly to maintain multiple enzymes
Need little energy to maintain temp (benefit)
Evaporative Heat Loss
Behavioral Responses
4 major processes
Conduction: lose or gain heat by contact
Radiation: emission of electromagnetic radiation
Convection: lose or gain heat by air removing/adding radiated heat
Evaporation: loss of heat by evaporation of water
sweat glands and panting aid this
heat is carried away along with water in evaporation from body surface
lizard to sun, scorpion to burrow, etc
cooling or warming oneself based on heat source
behavioral adaptations
Torpor (short hibernation ie hummingbirds)
frogs with anti-freeze in blood
Hibernation (body temp varies greatly, lowers metabolic rate significantly)
Energy Requirements of Thermoregulation
Minimum Metabolic Rate and Thermoregulation
Influences
Related to Animal Size, Activity, and Environment
Ectotherms have a SMR not a BMR
BMR measured under comfortable temp range
Size
Activity
Torpor/Hibernation
Takes more energy to maintain BMR of smaller animal per kg than bigger animals
bigger animals require more energy, but BMR per kg is lower than in small animals
Maximum metabolic rate an organism can sustain is inversely related to duration of activity
Consumes energy beyond BMR and SMR
Osmoregulation
In environment
Land Animals
Osmoconformors and Osmoregulators
Hyperosmotic
Hypoosmotic
Isosmotic
most likely an osmoconformor
water in organism = water in environment
live in fresh water
Gains large amounts of water through osmosis, has to pee a lot
water in organism < water in environment (water moving in, salt moving out)
salt water environments
Makes them dehydrated
water in organism > water in environment (water moving out, salt moving in)
Constantly processing salt in sea water
constantly drinking seawater to stay hydrated and compensate for water loss
Adaptations to Prevent Water Loss
Obtain water through eating and drinking, lose through excretions and secretions (pee and sweat)
Amniotic egg protects embryo from dessication
Thicker skin doesn't allow water out as easily