Practice A4.1 Evolution and speciation 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.
Paper
Level
Question 1
SLPaper 1A
The forelimb of a whale, the wing of a bat, and the arm of a human all contain a similar bone arrangement but serve different functions. Which explanation best supports this observation?
Question 2
SLPaper 1A
The forelimbs of humans, cats, whales, and bats contain the same bones in different arrangements. What is this an example of?
Question 3
SLPaper 1A
A population of fish in a lake gradually splits into two groups that no longer interbreed. What must be true for this to be classified as a speciation event?
Question 4
SLPaper 1A
Pentadactyl limbs are found in a range of vertebrates, including whales and bats. Which statement best explains the evolutionary significance of this?
Question 5
SLPaper 1A
What happens to global species diversity during a speciation event?
Question 6
SLPaper 1A
The following table shows the base sequences of a gene from different species. Which species pair shows the greatest evolutionary divergence?
| Species | Base Sequence (Segment) |
|---|---|
| Species A | ATG GCA TCC TGA GCT |
| Species B | ATG GCA TCC TGA GCA |
| Species C | ATG GCC TCT TGA GCG |
| Species D | ATA TGA ACC TAA ACC |
Question 7
HLPaper 1A
Based on the series of panels, what is the most likely explanation for why organisms from opposite riverbanks are no longer able to interbreed by the final stage?
2 populations of the same species.
separated by a physical barrier.
adapt to new environments.
New species formed.
Question 8
SLPaper 1A
DNA sequencing reveals a 98.8% similarity in gene sequences between humans and chimpanzees. What does this high similarity provide evidence for?
Question 9
SLPaper 1A
The table below shows amino acid differences in a protein between humans and several other species.
| Species | Amino Acid Differences from Human |
|---|---|
| Chimpanzee | 1 |
| Gorilla | 2 |
| Mouse | 15 |
| Chicken | 25 |
Which conclusion is best supported by this data?
Question 10
SLPaper 1A
Why is gradual evolutionary change in a population not considered speciation?