2.4 Criteria Flashcards
What is metabolic rate affected by?
Abiotic factors including temperature, salinity and pH
What is the internal environment of conformers dependent upon?
The external environment
What responses do conformers use to allow them to tolerate variations in the external environment?
Behavioural responses
What is an example of a behavioural response and the conformer that uses it.
Sunbathing in lizards
What does behavioural responses allow conformers to maintain?
An optimal metabolic rate
Do conformers have high or low metabolic costs?
Low
Do conformers have wide or narrow ecological niches?
Narrow
Do regulators rely on the external environment to maintain their internal environment?
No (internal environment of regulators is maintained regardless of the external environment).
What do regulators use to control their internal environment?
Metabolism
What is an example of internal environments controlled by metabolism?
Temperature, water balance, blood sugar.
Define Homeostasis:
The use of physiological mechanisms to maintain internal body conditions at optimum levels.
What do regulators expend energy on?
To achieve homeostasis
Will homeostasis increase or decrease metabolic costs?
Increase
Do regulators have a wide or narrow ecological niche?
Wide
Define thermoregulation:
The maintenance of a constant internal temperature
What is the hypothalamus?
Is the temperature monitoring centre
How is information communicated from the hypothalamus to effectors through nerves?
Temperature change is felt by effectors in the skin. Impulses are sent from effectors in skin to hypothalamus in brain. It contains thermoregulators. Impulses are sent back to effectors from the thermoregulators and a change is made.
What is negative feedback control?
Negative feedback control uses corrective responses to reverse changes in internal temperature to return temperature to normal (the set point)
Explain the human response (sweating) to an increase in body temperature?
Body heat is used to evaporate water in sweat thereby cooling the skin.
Explain the human response ( vasodilation) to an increase in body temperature?
Increased blood flow to the skin increases heat loss by radiation.
What does a reduction in metabolic rate also reduce?
It reduces heat production
Explain the human response (shivering) to a decrease in body temperature?
Rapid involuntary muscle contraction generates heat.
Explain the human response (vasoconstriction) to a decrease in body temperature?
Decreased blood flow to the skin decreases heat loss by radiation.
Explain the human response (contraction of hair erector muscles) to a decrease in body temperature?
Traps a layer of insulating air.
What does an increase in metabolic rate also increase?
Increases heat production
What is the maintenance of body temperature required for?
Its required for optimal enzyme activity
What does the maintenance of body temperature ensure?
Ensures high diffusion rates required to maintain metabolism
