Symbiosis Lesson 2026

Symbiosis

Symbiosis is a close relationship between 2 or more organisms of a different species. There are 3 main types of symbiosis:

1. mutualism

2. commensalism

3. parasitism

What do you think is going in this relationship between the fish and the hippopotamus?

Mutualism: When both species benefit.

Commensalism: One species is helped and the other is not harmed or helped

Multiple Choice

A lion stalks a herd of antelope wading in a pond. A flock of water birds on the shore become startled by the sound of the lion’s approach and fly away with a great deal of noise. The birds’ sudden departure gives warning to the antelope, and they are also able to escape safely. What type of relationship exists between the birds and the antelope?

• competition

• mutualism

• commensalism

• parasitism

Drag and Drop

Symbiotic relationships ​

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biodiversity​ because, often, the different species support each other to thrive and survive.

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increase

decrease

Match

Match the following types of relationships to their descriptions:

• Both organisms are harmed by fighting over a resource

• One organism benefits at the expense of the other

• One organism benefits while the other remains neutral

• Both organisms benefit (help each other)

Competition

Parasitism

Commensalism

Mutualism

• Competition

• Parasitism

• Commensalism

• Mutualism

Drag and Drop

​

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is a common type of symbiosis because all the species involved benefit. For example, a hummingbird drinks ​

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from a flower, gaining food. The flower is ​

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by the bird. Both species help each other.

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Mutualism

nectar

pollenated

Parasitism

Drag and Drop

In ​

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, one species harms another species to benefit themselves. For example, a flea bites a dog to get ​

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. This leaves the ​

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with itchy bite marks.

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parasitism

food

dog

commensalism

flea

Multiple Choice

A cowbird lays its eggs in the nest of another bird. The other bird expends energy to take care of the baby, finding it food until it's big enough to leave the nest. What kind of relationship is this?

• parasitism

• mutualism

• commensalism

• competition

Multiple Choice

Barnacles create home sites by attaching themselves to whales.

• Mutualism

• Commensalism

• Parasitism

Multiple Choice

Ticks feed on deer blood with harms the deer.

• Mutualism

• Commensalism

• Parasitism

Multiple Choice

Yucca flowers are pollinated by yucca moths. The moths lay their eggs in the flowers. Both species benefit.

• Mutualism

• Commensalism

• Parasitism

Multiple Choice

Hermit crabs live in shells made and then abandoned by snails.

• Mutualism

• Commensalism

• Parasitism

Multiple Choice

Honey guide birds alert and direct badgers to bee hives. The badgers feed on the honey and then allow the birds to eat.

• Mutualism

• Commensalism

• Parasitism

Multiple Choice

Mistletoe extracts water and nutrient from the spruce tree it is attached to.

• Mutualism

• Commensalism

• Parasitism

Poll

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