Problem 1
- Test level
- Multiple choice
- No calculator
- 4 pts
In fictional equal-resource trials, adding a second individual of species S reduces the first S's growth from 8 to 5 units. Adding an individual of species T instead reduces it from 8 to 6. The limiting resource is the same shared food, and all other conditions are held fixed. Which interpretation matches the records?
Answer
The first demonstrates within-species competition and the second between-species competition under these conditions.
Full solution
The same-species neighbor reduces the focal S outcome by 3 units.
The different-species neighbor reduces it by 2 under the same limiting-food condition.
The records therefore distinguish within-species from between-species competition rather than restricting competition to only one.
Where students lose points
Defining competition from species identity alone instead of the controlled shared-resource effect.

