Question 19M.2.SL.TZ1.b
| Date | May 2019 | Marks available | [Maximum mark: 3] | Reference code | 19M.2.SL.TZ1.b |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Explain | Question number | b | Adapted from | N/A |
The niches of the red and grey squirrels overlap. Explain the concept of competitive exclusion with respect to the changes in squirrel distribution shown in the maps.
[3]
a. competitive exclusion states two species that occupy a similar niche in the same location cannot coexist ✔
b. one of the two competitors will always have an advantage over the other ✔
c. leads to extinction/displacement/evolution of the second competitor ✔
d. grey squirrels have replaced/occupied niches formerly occupied by red squirrels
OR
habitats favour the grey squirrel in competition for the niche ✔
e. the niche of one competitor/both competitors becomes narrower ✔
This question was yet another instance where weaker students were disadvantaged by their inability to access the appropriate subject-specific vocabulary. They tended not to use the term “niche” with this question, and too frequently “niche” and “habitat” were confused.
