U2.4 Conformers and regulators

Question 1

What is the metabolic rate of an organism affected by?

Answer 1

Abiotic factors including temperature, salinity and pH.

Question 2

What is a conformer?

Answer 2

Any organism whose internal environment is highly influenced by external factors.

Question 3

How do conformers maintain their metabolism?

Answer 3

They can only live in conditions that support their metabolism. Behavioural responses are used to maintain metabolic rate.

Question 4

Describe the metabolic cost and range of ecological niches of a conformer.

Answer 4

Low metabolic cost, narrow range of ecological niches.

Question 5

What is a regulator?

Answer 5

Any organisms that are able to withstand differences in their external environment because they can control their internal environment (within limits).

Question 6

How do regulators use metabolism to do?

Answer 6

Regulate their internal environment at a steady state, e.g. water balance, temperature, blood sugar.

Question 7

Describe the metabolic cost and range of ecological niches of a regulator.

Answer 7

Increased metabolic cost, greater range of ecological niches.

Question 8

What is homeostasis?

Answer 8

The use of physiological mechanisms to maintain internal body conditions at optimum levels.

Question 9

Why do regulators have an increased metabolic cost?

Answer 9

They expend energy to achieve homeostasis.

Question 10

Why do conformers use behavioural responses?

Answer 10

To allow them to tolerate variations in the external environment e.g. sunbathing in lizards.

Question 11

What are ectotherms?

Answer 11

Conformers that use behavioural mechanisms to regulate temperature. Main behavioural is basking.

Question 12

What are the pros and cons of ectotherms?

Answer 12

Pro - have a low metabolic cost.

Con - ecological range is narrow, so any extreme can cause problems.

Question 13

What are endotherms?

Answer 13

Temperature regulators. They use physiological processes to maintain body temperature (homeostasis).

Question 14

Define thermoregulation.

Answer 14

The maintenance of a constant internal temperature.

Question 15

What is the temperature monitoring centre, and where is it located?

Answer 15

Hypothalamus, the brain.

Question 16

How is information communicated from the hypothalamus to effectors through nerves?

Answer 16

FOR INC TEMP
-Increase in factor is detected by hypothalamus
-Effector e.g. sweating vasodilation, reduced metabolism
- Returns to normal body temp (37)
FOR DEC TEMP
-Decrease in factor is detected by the hypothalamus
-Effector e.g. hair erector muscles contract, vasoconstriction, shivering

Question 17

State some effectors inthermoregulation.

Answer 17

Hair erector muscles, sweat glands, skin arterioles, muscles (if cold).

Question 18

State some effectors inthermoregulation.

Answer 18

Hair erector muscles, sweat glands, skin arterioles, muscles (if cold).

Question 19

What are the human responses to an increase in body temperature?

Answer 19

Sweating - body heat used to evaporate water in sweat thereby cooling skin.
Vasodilation - increased blood flow to the skin increases heat loss by radiation.
Reduction in metabolic rate - reduces heat production.

Question 20

What are the human responses to a decrease in body temperature?

Answer 20

Shivering - rapid involuntary muscle contraction generates heat.
Vasoconstriction - decreases blood flow to the skin decreases heat loss by radiation.
Contraction of hair erector muscles - traps a layer of insulating air.
Increase in metabolic rate - to produce more heat.

Question 21

Why is body temperature required to be maintained?

Answer 21

For optimal enzyme activity.

Question 22

What does the maintenance of body temperature ensure?

Answer 22

High diffusion rates required to maintain metabolism.