Living together: who gains?
Some living things live close together. Who gains? Who is harmed?
Step 1 of 4
- Three pairs of living things share a place.
- Mutualism: both gain. Bean plants and the bacteria in their roots.
- Commensalism: one gains, the other is neither helped nor harmed. Suppose a bird shelters in a tree.
- Parasitism: one lives on the other and harms it. Amarbel on a host plant.
It depends on the pair. In some, both gain. In some, one is harmed.
New words
- Competition — two living things need the same food, water or space. There is not enough for both.
- Parasite — a living thing that lives on or in another, harming it.
The living thing a parasite lives on is its host. Amarbel is a plant without green leaves. It takes food from its host.
The rule
Mutualism: both partners gain. Commensalism: one gains, and the other is neither helped nor harmed. Parasitism: one lives on or in the other and harms it.
Living things that share food or space compete when it runs short. Competition is one limit on how many can live in a place.
Watch out!
A parasite lives on or in the one it harms. A predator hunts other animals for food. A tiger that kills a deer is a predator, not a parasite.
Set what each one gets. Read the name.
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