Q99 — Competitive Displacement Between Two Hare Species in Newfoundland

Theoretical 2 Real exam question — full text reproduced under IBO's CC BY-NC-SA 4.0 license

Newfoundland was originally only inhabited by one species of hare, the arctic white hare Lepus arcticus (up to 70 cm in length and up to 7.0 kg). It has previously been found both in open fields and in the woods of Newfoundland, feeding on grasses, various parts of trees and shrubs. Around 100 years ago, the small white hare Lepus americanus (up to 52 cm in length and up to 1.55 kg) was introduced to the island. Lepus arcticus currently inhabits only open areas and Lepus americanus inhabits only forested areas. The forested areas are also inhabited by a predator of hares — the Canada lynx Lynx canadensis.

Photograph of Lepus arcticus, a large white hare standing on snow with long, upright ears. Lepus arcticus (arctic white hare).

Photograph of Lepus americanus, a smaller white hare sitting in snow among sparse forest brush. Lepus americanus (snowshoe hare).

Photograph of Lynx canadensis, a lynx. Lynx canadensis (Canada lynx), the forest-dwelling predator of hares in Newfoundland.

Using the information and images, indicate whether the following statements are true or false.

A. Lepus americanus has pushed Lepus arcticus out of the wooded area because it is physically stronger and more adapted to living in a wooded area.

B. Lepus arcticus feeds only on herbs, and Lepus americanus only on bark and branches of trees.

C. Living in the open fields, Lepus arcticus avoids becoming prey to Lynx canadensis.

D. Lepus arcticus later moved out of wooded areas to avoid being predated on by Lynx canadensis.

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Question reproduced from IBO 2022, Theoretical Paper 2, licensed under CC BY-NC-SA 4.0 — attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)