IB Biology HL 3.1.4 Cladistics and Species Concepts
Practise IB Biology HL 3.1.4 by evaluating species criteria, hybrids, isolation and genetic evidence for species boundaries.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- Evaluate biological species criteria against hybrids, asexual organisms, geographic isolation and morphological variation.
- Use Canis haplotypes and reproductive evidence to discuss hybridisation and species boundaries.
A3.1.4—Biological species concept question 1
[Maximum number: 2]
A species is often defined as a group of similar individuals that interbreed in nature and produce fertile offspring. Discuss some problems with the use of this definition.
a not all organisms can be defined in this way / does not take into account hybrids/ microorganisms/plants;
b. (even if able to interbreed) may have differences in DNA/protein;
c. does not apply to bacteria/other organisms that reproduce asexually;
d. in sympatric/allopatric isolation members of the same species do not interbreed;
e. (in some species) significant differences in morphology can occur within the same species eg: sexual dimorphism/metamorphosis/ring species;
Marking guidance:
Accept any other correct answer.
All question bank results loaded