CourseCourseConceptConceptDocsDocuments

IB Biology HL C4.1.14 Tests for Interspecific Competition Questions

Evaluate field-comparison evidence for competition, controls, removal designs and fundamental-versus-realized niche effects in IB Biology HL C4.1.14.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • Design or evaluate a competition test using controls, removal or coexistence comparisons, with repeated abundance or distribution measurements and a defined resource or habitat variable.
  • Interpret competition data to distinguish fundamental from realized niche effects and judge whether population displacement supports competitive exclusion.

IB Biology HL C4.1.14 Tests for Interspecific Competition Questions question 1

[Maximum number: 2]

In South Korea, flocks of birds of the tit family (Paridae) forage together on trees for food. Researchers observed four species of Paridae to determine whether they shared the same habitat in the trees and whether their position on the tree depended on their size. The leafy part of the tree (crown) was divided into nine sections, three according to height from the ground and three according to the distance from the tree trunk. Observations were also made of birds foraging in the bushes surrounding the trunk and on the ground below the tree. The chart shows the relative use of each section of the habitat by the birds.

Table for Question IB Biology HL C4.1.14 Tests for Interspecific Competition Questions question 1 — IB Biology HL
Table for Question IB Biology HL C4.1.14 Tests for Interspecific Competition Questions question 1 — IB Biology HL

Discuss whether the results for the Varied Tit and Coal Tit indicate competitive exclusion.

All question bank results loaded