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