Grade 7 revision lessons 3-4

There are several different types of symbiotic relationships. In this case, a tick attaches to an animal and feeds on its blood. Ticks need blood at every stage of their life cycle. Ticks can also spread disease to the animals when they penetrate the animal's skin while sucking its blood. What type of symbiotic relationship is this? Explain.

• Predation. The tick is predator while the dog is its prey.

• Parasitism. The tick derives benefit while the dog is harmed.

• Commensalism. The tick derives benefit but the dog is not harmed.

• Mutualism. Both animals are potentially harmed in the relationship

Increased food supplies in an ecosystem decrease competition because the competing organisms would...

• reproduce more often.

• have enough food to eat.

• store large quantities of food.

• have more space in which to live.

A lion would be considered a ________ of a gazelle.

• competitor

• offspring

• predator

• prey

In Africa, as the crocodile lies with its mouth open, the plover, or crocodile bird, flies into its mouth and feeds on bits of meat stuck in the crocodile’s teeth. The crocodile does not harm the plover. The plover gets a meal and the crocodile gets his teeth cleaned. What conclusions might be drawn regarding the dynamics of this relationship?

• It is a mutualistic relationship because both animals benefit; neither animal is harmed.

• It is a symbiotic relationship because the plover benefits from the meat in the crocodile's teeth..

• The crocodile is a predator. The plover is a parasite. There are two relationships illustrated by this dynamic.

• It is an example of commensalism because the plover benefits from the relationship while the crocodile is neither helped or harmed.

There are three main types of symbiotic relationships: mutualism, commensalism, and parasitism. Which image depicts commensalism?

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This is a type of symbiotic relationship where both organisms benefit.

• commensalism

• competition

• mutualism

• parasitism

The picture is an example of ___________ between the wolves.

• competition

• commensalism

• mutualism

• parasitism

A bear catching and eating a salmon from a river is an example of...

• predation

• commensalism

• mutualism

• parasitism

A clownfish lives in an anemone. The anemone protects the clownfish by shocking the clownfish's predators. The clownfish protects the anemone from predators that may want to snack on the anemone. What is this relationship an example of?

• parasitism

• mutualism

• predation

• commensalism

Some birds live among cattle to eat the insects that the cattle stir up when they are grazing. The relationship between the cattle and the birds is an example of...

• mutualism

• parasitism

• commensalism

• predation