Unit 2 Key area 4

Question 1

State three examples of external abiotic factors that affect the ability of an organism to maintain its metabolic rate?

Answer 1

• temperature
• Salinity
• pH

Question 2

Explain what the term conformer relates to?

Answer 2

The term conformer relates to organisms in which their internal environments are dependant on the external environment of the organism. Conformers use behavioral responses to maintain their optimal metabolic rate. Conformers have low metabolic costs and a narrow range of ecological niches.

Question 3

Explain what the term regulator means?

Answer 3

A regulator is an organisms that maintains its internal environment regardless of the external environment. Regulators use metabolism to maintain their internal environment, this increases their range of ecological niches and also means that they have higher metabolic costs than conformers.

Question 4

State the role of the hypothalamus?

Answer 4

The hypothalamus acts as the temperature monitoring center

Question 5

Describe the process of thermoregulation by negative feedback?

Answer 5

The hypothalamus detects a change in temperature and then sends electrical impulses through the nerves to the effector tissues that then use a corrective response method to return temperatures back to normal

Question 6

State three corrective responses that can be used to respond to an increase in body temperature?

Answer 6

• Sweat (body heat used to evaporate water cooling the body)
• Vasodilation (Increases blood flow to the skin increasing heat loss)
• Decreased metabolic rate (causes a decrease in the heat produced by the body helping to reduce body temperatures back to normal levels)

Question 7

State four corrective responses that can be used as a response to a decrease in body temperature?

Answer 7

• Shivering (muscle contraction here generates heat)
• Vasoconstriction (decreased blood flow decreased heat loss)
• Higher metabolic rate (produces more heat)
• Hair erector muscles contract (causes a thin layer of air to become trapped acting as insulation reducing the amount of heat lost)

Question 8

Explain why thermoregulation is important?

Answer 8

• thermoregulation is required to maintain optimal enzyme activity
• thermoregulation is required to maintain high diffusion rates which maintains metabolism