I keep getting “Population interactions” questions wrong in Ecosystem. What's the trap?
mixing up commensalism and mutualism.
The usual trap: mixing up commensalism and mutualism. How to avoid it: mutualism = both gain; commensalism = one gains, the other is unaffected. Go back to the definition — mutualism benefits both (+/+), competition harms both (-/-), predation and parasitism help one and harm the other (+/-), and commensalism helps one while the other is unaffected (+/0).
Key point
Population interactions
Common mistake
mixing up commensalism and mutualism.
Memory tip
mutualism = both gain; commensalism = one gains, the other is unaffected.
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