Practice C4.1 Populations and communities with authentic IB Biology exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like cell biology, genetics, and ecology. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
A community in ecology refers to:
The Lincoln index is used to estimate populations of:
In a mark–recapture study, the following were recorded:
What is the estimated population size?
Why is random sampling often used in population studies?
A population of wildflowers appears to fluctuate year by year. Quadrat sampling shows lower densities during droughts, followed by recovery.
Which combination best explains this pattern?
In a mark–recapture study, the second sample contains disproportionately fewer marked animals than expected, even though no births or deaths occurred.
What does this most likely indicate?
A species of pine secretes toxins that inhibit nearby root growth. However, fungi living symbiotically on the pine roots are unaffected.
Which conclusion is best supported?
What type of interaction is mutualism?
A student conducted a random quadrat sampling study in a meadow to estimate the population of buttercups. The results are shown below.
| Quadrat Number | Area (m2) | Number of Buttercups Counted |
|---|---|---|
| 1 | 1.0 | 6 |
| 2 | 1.0 | 4 |
| 3 | 1.0 | 7 |
| 4 | 1.0 | 3 |
| 5 | 1.0 | 5 |
The total area of the meadow is 100 m². What is the best estimate for the total population of buttercups in the meadow?
How do invasive species outcompete endemic ones?