Q33 — Dormouse Litters — Growth Rate and Energy Intake

Theoretical 1 Real exam question — full text reproduced under IBO's CC BY-NC-SA 4.0 license

The active period of the dormouse Eliomys quercinus is 6–7 months, during which the animals give birth to two litters. The gestation period is 1 month and 1 month is spent feeding the offspring, so first-litter offspring are two months older than second-litter offspring. Scientists studied the effect of birth date on growth rate and activity, dividing pups into unlimited-food (AL, ad libitum) and intermittently-fasted (IF, food withheld 24h twice weekly) subgroups. Growth was measured by body length, activity by metabolic rate (energy consumption, MJ).

Two graphs: body length and energy consumption vs. time, for early-litter (EB) and late-litter (LB) dormouse pups under ad libitum (AL) and intermittently fasted (IF) conditions. EB (early-litter) and LB (late-litter) pups, under AL (ad libitum, unlimited food) and IF (intermittently fasted) conditions. Left: body length vs. time. Right: energy consumption vs. time.

Using the information and graphs, determine whether the following statements are true or false:

A. Late-litter dormice were more susceptible to malnutrition and had significantly lower growth rates than early-born ones.

B. The late-litter pups gradually increased their food intake, while the first-litter ones immediately began to eat a lot, stopping eating only before overwintering.

C. Late-litter offspring were born smaller but grew faster, reaching the level of early-litter ones in a relatively short period of time.

D. The metabolism of fasting pups was lower than that of fully fed pups, but as overwintering approached, it gradually decreased in all pups.

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Question reproduced from IBO 2022, Theoretical Paper 1, licensed under CC BY-NC-SA 4.0 — attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)