2.4 Metabolism in conformers and regulators

• State the abiotic factors that can affect an organism's metabolic rate.

  Salinity

  pH

  Temperature
• Explain the purpose of the abiotic tolerance curve graph.

  Shows the range of an abiotic factor that an organism can survive in.
• What are the two categories that organisms can be classified under when reacting to changes in the external abiotic factors.

  Conformers

  Regulators
• Describe a conformer.


  A conformers internal environment is dependent upon it external environment. This means that the internal environment of a conformer fluctuates at the same time as the external environment.
• Give examples of behaviours of a conformer.

  -lizards basking in the sun

  -Limpets seal tightly to rocks to prevent dehydration at low tide

  -Earthworms burrow deeper underground during dry weather to avoid dehydration
• Describe a regulator.


  Regulators maintain their internal environment regardless of external environment.

  -This means that the internal environment of a regulator is constant, despite changes in the external environment.

  -The advantage of being a regulator is that they can exploit a wider range of possible ecological niches allowing them to be more adaptable to environmental change.

  -The disadvantage of being a regulator is that they tend to have high metabolic costs as they require energy to regulate their internal environment.
• Describe the term 'Homeostasis'


  Is the maintenance of the body's internal environment within tolerable limits, despite changes to the external environment.
• Define the term 'thermoregulation'


  The process that allows a mammal or bird to maintain its core internal temperature.
• Thermoregulation is maintained by what process?

  Negative feedback.
• Explain how thermoregulation occurs when the temperature falls below the minimum tolerant level.

  -Shivering: rapid muscle contraction which generates heat.

  -Vasoconstriction: Decreased blood flow to the skin decreases heat loss by radiation.

  -Contraction of hair erector muscles: Traps a layer of insulating air.

  -In crease in metabolic rate: To produce more heat.
• Explain how thermoregulation occurs when the temperature increases above the maximum tolerant level.

  -Sweating: Body heat is used to evaporate water in sweat thereby cooling the skin.

  -Vasodilation: Increased blood flow to the skin increases heat loss by radiation.

  -Reduction in metabolic rate: To reduce heat production.
• Describe the function of the hypothalamus.

  The body's temperature monitoring centre. It acts as a thermostat using negative feedback control to keep the body temperature within tolerable limits.
• State how the information from the hypothalamus reaches the effectors to produce the correct response.

  Electrical impulses through nerves to the effectors, which bring about corrective responses to return temperature to normal.