Relationship

What do you call a close relationship between two different species?

• symbiosis

• friendship

• community

• coevolution

Answer explanation

Symbiotic relationships are all the different types of close relationships between different species.

Match the following types of relationships to their descriptions:

• Competition

• One organism benefits at the expense of the other

• Mutualism

• One organism benefits while the other remains neutral

• Commensalism

• Both organisms benefit (help each other)

• Parasitism

• Both organisms are harmed by fighting over a resource

Macaws (a large, tropical bird) have strong beaks that can bit through thick shells. They are messy eaters, often opening nuts and droping them on the ground, leaving them behind. Other animals eat the dropped food. What type of relationship is this?

• commensalism

• parasitism

• mutualism

• competition

Answer explanation

Commensalism is when one species benefits (the animals eating the dropped food) while the other is neutral (the Macaw).

Match the following types of relationships to their descriptions:

• Competition

• 
• Parasitism

• 
• Commensalism

• 
• Mutualism

• 

Aztec ants live in Cecropia trees. The tree provides a home for the ants and the ants protect the tree from herbivores. What kind of relationship is this?

• parasitism

• mutualism

• competition

• commensalism

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 next. What kind of relationship is this?

• parasitism

• mutualism

• commensalism

• competition

Which of he following interactions demonstrates a PARASITIC relationship?

• A mosquito sucking blood from a warm blooded animal.
• A group of baby otters floating together to help warm each other in the cold waters.
• Many fish swimming together to protect each other from predators.
• Two hyenas fighting over a female to mate with.

In the jungles of South America lives a thorn tree call an acacia. A species of ant eats secretions of the acacia, drinks its sap, and raises its young in the hollow thorns. The ants also keep competing vines from growing near the acacia tree and they help repel any insects that would damage the acacia tree.

• mutualism

• commensalism

• parasitism

Lichens are close associations of fungi and algae. The fungi hold the water supply and the algae perform photosynthesis to manufacture carbohydrates for both organisms.

• mutualism

• commensalism

• parasitism

How is commensalism different from mutualism?

• In commensalism, one species benefits while the other is unharmed; in mutualism, both species benefit

• In commensalism, one species is harmed while the other benefits; in mutualism, both species benefit

• In commensalism, neither species is harmed; in mutualism, one species is harmed

• In commensalism, both species benefit; in mutualism, one species is harmed