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IB Biology HL A3.1.12 Hl Difficulties with Biological Species Concept Questions

The biological species concept does not apply well to asexual organisms. Bacteria gain diversity through mutation and horizontal gene transfer; transformation, plasmids and recombination can blur bacterial species boundaries.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • Explain why the biological species concept does not apply well to asexual organisms.
  • Explain how mutation and horizontal gene transfer create diversity in bacteria.
  • Explain how transformation, plasmids and recombination blur bacterial species boundaries.

IB Biology HL A3.1.12 Hl Difficulties with Biological Species Concept Questions question 1

[Maximum number: 1]

The gut of a healthy human contains more than 1000 species of bacteria. Some of these species are shown in the cladogram.

Cladogram with species X branching beside a group containing M. luminyensis and paired M. smithii/M. stadmanae. A separate main branch contains E. faecalis and paired B. fragilis/B. stercosis.

Outline a difficulty in applying the biological species concept to bacteria.

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