Background: Predators play an important role in an ecosystem. For example, if they did not exist, then a single species could become dominant over others. Grazers on a grassland keep grass from growing out of control. Predators can be keystone species . These are species that can have a large effect on the balance of organisms in an ecosystem. For example, if all of the wolves are removed from a population, then the population of deer or rabbits may increase. If there are too many deer, then they may decrease the amount of plants or grasses in the ecosystem. Decreased levels of producers may then have a detrimental effect on the whole ecosystem. In this example, the wolves would be a keystone species.

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: What animimal keeps the savanah from becoming a forest?

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: What tree controlled by elephants?

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: What would herd populations increase or decrease if the trees took over?

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: Would lion populations increase or decrease if herd animals die?

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: Would trees increase or decrease without elephants?

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: would heyena's have enough or too little food if herd animals didn't have grass?

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: What animal allows grass to thrive on the savanah?

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: Would scavangers thrive or starve if predator populations declined?

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: Would herd animals return to the area or move if grass was scarce?

Situation: Elephants eat shrubs and small trees, such as acacia, that grow on the savanna. Even if an acacia tree grows to a height of a meter or more, elephants are able to knock it over and uproot it. With few trees grass is able to thrive.

Question: Woukld the stould stay dry or hold more moisture if there were more trees?

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: What predator was removed from the environment?

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: What animal was prey to the wolves?

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: What animal no longer has a natural predator?

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: What animal is destroying the forest?

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: What is being over eaten?

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: What population is increasing?

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: What population will run out of food eventually?

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: What disrupted the balance of the ecosystem?

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: Returning what animal could restore balance to the ecosystem??

Situation: When wolves became extinct in the area ranger in  Yellowstone National Park noticed that the elk population was increasing. At the same time they noticed that the environment changing. The forest and plant life was being destroyed.

Question: What animal is a keystone species in Yellowstone National Park?