Biology 9700 · AS & A Level · Homeostasis in mammals

Homeostasis in mammals — practice question

Thermoregulation refers to the maintenance of the body’s core temperature. Thermoreceptors transmit details of any change in core temperature to the hypothalamus. The hypothalamus maintains core temperature by sending impulses that trigger a range of physiological responses. Table 6.1 shows physiological responses when core temperature falls.
(a)[4]

Use Table 6.1 to show how each response helps keep core temperature within narrow limits.

(b)[1]

Animals can also use behaviour to cope with changes in temperature. Suggest why some animals curl up their bodies in cold weather.

(c)[4]

The Sitatunga deer, $\textit{Tragelaphus spekii}$, and the Nile monitor lizard, $\textit{Varanus niloticus}$, live in Africa. An experiment measured the core temperature of the Sitatunga and the Nile monitor as environmental temperature was increased. The findings are shown in Fig. 6.3. (i) Describe the results in Fig. 6.3. (ii) At low environmental temperature, Nile monitors are fairly inactive. Suggest one disadvantage to the Nile monitor of being inactive.

(d)[3]

Thermoregulation depends on negative feedback. Explain what is meant by negative feedback.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: vasoconstriction lowers heat loss

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI