Living in the same place isn't competing
- The idea
- Predict
- See it
- Why
- Check
The idea
“If two species live in the same place, they must be competing.”
A crowded pond looks like a fight for space, so any two neighbors seem like rivals. Many use different things, and some even help each other.
The short version
The mistake: If two species live in the same place, they must be competing.
What's actually true: Two species compete only when each one uses up a limited resource that the other needs.
- Competition means each species uses up a resource the other needs, like food, light or space, and there isn't enough for both.
- Sharing a place only makes competition possible. Neighbors may use different resources, help each other, or one may eat the other.
- To test it, remove one species. If the other increases, and the reverse holds too, they were competing.
On the exam: Before calling two species competitors, name the limited resource each takes from the other.