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← Theoretical A

Q2 — Strigiformes (Owls) Phylogenetic Identification

Theoretical A Real exam question — full text reproduced under IBO's CC BY-NC-SA 4.0 license
Phylogenetic Trees & Cladistics

You are given five species of birds from the Strigiformes order (Owls), commonly found in Kazakhstan (Figure 1A). However, the genera to which these species belong are unknown to you. To ascertain this, you were provided with information depicted in the figures below.

Panel A: photos of five numbered owl species, each with a row of colored area-code boxes (some hidden behind question marks) below. Panel B: a phylogenetic tree of Strigiformes genera spanning 60 million years, with each genus’s full area-code list and species count in parentheses. Figure 1. A Five bird species; the bottom row in each box represents the partial list of the birds’ inhabiting areas (refer to Figure 2). B Phylogenetic tree of the Strigiformes order with their full inhabiting area lists. The number of species that make up the corresponding genus is indicated in parentheses.

Color-coded legend mapping each colored box to a geographic area: South America, Central America, North America, Eurasia, Africa, Madagascar, Philippines, Australia, New Zealand. Figure 2. Area distribution key; each rectangle corresponds to a certain area.

It is also known that:

  • Species 3 and 5 share the most recent common ancestor that lived 5 million years ago.
  • Species 2 and 3 share the most recent common ancestor that lived 20 million years ago.
  • Species 5 and 4 share the most recent common ancestor that lived 40 million years ago.
  • The genus to which species 1 belongs has never been found in the Philippines.

On your answer sheet, indicate “T” for true statements and “F” for false ones.

A. One of the five listed species is the only representative of its genus.
B. Constructing a phylogenetic tree using this data reveals that species 1 and 4 are the second most closely related among the five species.
C. Some of the five given species belong to the same genus.
D. A migration (in terms of species dispersal) from America to Africa and Eurasia is a more parsimonious explanation for the geographic distribution of Strix compared to a migration in the opposite direction.
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Question reproduced from IBO 2024, Theoretical Exam Part A, licensed under CC BY-NC-SA 4.0 — attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)