Chapter 40 - Basic Principles of Animal Form & Function Flashcards
Describe negative feedback.
A mechanism of homeostasis; where a change in a variable triggers a response that counteracts the initial change.
Describe positive feedback.
A control mechanism in which a change in a variable triggers a response that reinforces or amplifies the change.
Describe an animal which is a regulator.
The animal’s internal conditions are independent of it’s external environment.
Describe an animal which is a conformer.
The animal’s internal condition changes with it’s external environment.
Describe an animal which is an endotherm.
Generate heat via metabolism which has high energy requirements which enables vigorous activity.
Describe an animal which is an ectotherm.
Uses external sources of heat, require less food, and can tolerate large fluctuations.
Describe an animal which is a poikilotherm.
Their body temperature varies with external temperature (ex: hibernating squirrel)
Describe an animal which is a homeotherm.
Their body temperature remains constant (ex: fish in stable waters)
Describe radiation.
Heat moving down temperature gradient via objects not in contact (ex: sun)
Describe convection.
Heat moving down temperature gradient via flow of moving liquid & gas (ex: cooling off in a river, wind)
Describe evaporation.
Heat moving down temperature gradient via hot liquid molecules escaping (ex: panting)
Describe conduction.
Heat moving down temperature gradient via direct contact between solids (ex: basking on a warm rock)
Describe adaptations that aid in thermoregulation.
- Circulatory
- Vasodilation
- blood flow increases, causes warming
- Vasoconstriction
- reduces blood flow & heat transfer, avoids overheating
- Countercurrent exchange
- Vasodilation
- Insulation
- Fat layer
- Feathers
- Fur
- Cooling by Evaporative Heat Loss
- Panting
- Sweating
- Bathing
- Behavioral Responses
- Avoiding undesired temperatures (moving toward or away!)
- Huddling together (if cold)
- Fanning (if hot)
- Adjusting Metabolic Heat Production
- Endotherms vary heat production (“thermogenesis”) to match changing rates of heat loss
- ex: shivering
- “Nonshivering thermogenesis” causes mitochondria to increase metabolic activity
- ex: “brown fat” specialized for rapid heat production
- Endotherms vary heat production (“thermogenesis”) to match changing rates of heat loss
Describe countercurrent heat exchange.
A mechanism in organisms that utilizes parallel pipes of flowing fluid in opposite directions in order to save energy.
Describe torpor.
The act of decreasing body temperature and metabolic rates to save energy during extreme environmental conditions using stored energy and/or food caches.
