WFC 130 Final

1. Futile cycling - Chemical potential energy is spent to generate heat.

2. Shivering thermogenesis - Heat production through uncoordinated stimulation of skeletal muscle contractile units

• 1. Behavioral regulation
• 2. *Insulation
• 3. Coloration
• 4. *Regulation of heat loss by changing circulatory patterns
• 5. *Thermogenesis

The relationship between a physiological rate and a 10C incremental change in temperature

• 1. Metabolism
• 2. Conduction
• 3. Convection
• 4. Radiation
• 5. Evaporation

The transfer of thermal energy from one region of an object or fluid to another

The transfer of thermal energy between an object and an external fluid that is moving

The emission of electromagnetic energy from an object

When water molecules from the surface of an object absorb thermal energy from an object

increased

decreased

decreases

Animals living in cold environments tend to be larger

Animals in colder climates have smaller extremities

creating a stagnant air boundary around an animal, resisting heat transfer

1. Alter the "effective" concentration or activity of an enzyme

2. Modify substrate concentration

3. Change the energy supply for the reaction being catalyzed

4. Alter the intracellular environment to improve the enzyme's effects

1. Alter the amount of protein (quantitative) - Increases as temperature decreases

2. Isoform switching (qualitative)

1. Alter the amount of constitutively expressed protein

2. Modify protein/enzyme structure for "optimal" function (alter km and/or kcat)

Rate of substrate turnover

Affinity for the substrate.

As km decreases, affinity increases

1. Thermal stability

2. kcat

3. km

warm

Molecular chaperones that catalyze protein folding and help refold denatured proteins

An increase in the levels of heat shock proteins in response to extreme temperatures

Membrane fluidity stays constant across large temperature changes.

greater

1. Age

2. Length of exposure

3. Recent history

4. Evolutionary history (adaptation)

1. Intracellular ice formation

2. Chemical reaction rates drop

3. CNS control, integration reduced

Higher solutes lower the freezing point

Isosmotic, freezing point equals that of seawater

No

hyposmotic

Yes

hyperosmotic

No

1. Lower freezing point by adding solutes

2. Elimination of ice nucleating sites

3. Produce antifreeze

The ability to remain unfrozen when body temperature drops below freezing point

Only occurs in deep water marine teleosts because won't encounter ice

Bind to ice crystals

Intertidal invertebrates

Overwintering insects

Amphibians

1. Shivering

2. Nonshivering thermogenesis

3. Allow portions of the body to cool (regional heterothermy)

1. Active evaporative water loss

2. Hyperthermia

1. Insulation

2. Change in posture

3. Erection of insulation

4. Alter blood flow

A thermoregulatory strategy in which regions of an animal's body exhibit significantly different temperatures

Limit heat loss by letting appendages cool

Exacerbate heat loss by increasing blood flow to area

1. Reduces gas exchange

2. Reduces waste removal

The extremities of an animal

Ex: legs or flippers

Complex of vessels that keeps the brain cool

Allows animals to tolerate adaptive hyperthermia in rest of the body

Increases surface area, thus increasing contact with outside air, cooling blood

- Increased aerobic metabolism = higher level of activity

- Increased nerve transmissions and visual acuity

- Warm stomach allows for fast digestion

- Freedom of movement through thermocline to chase prey

- Range expansion into polar waters