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: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: Which country would see more rodents in agricultural lands, France or Germany?
Answer: Germany

Situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: Which country would see less rodents in agricultural lands, France or Germany?
Answer: France

Situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: Would France see less or more rodents in agricultural lands than Germany?
Answer: less

Situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: Would Germany see less or more rodents in agricultural lands than France?
Answer: more

Situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: Which country would see more crops produced, France or Germany?
Answer: France

Situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: Which country would see less crops produced, France or Germany?
Answer: Germany

Situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: Would France see less or more crops porduced than Germany?
Answer: more

Situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: Would Germany see less or more crops porduced than France?
Answer: less

Situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: In which country ecosystem would be more balanced, France or Germany?
Answer: France

Situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France.

Question: In which country ecosystem would be less balanced, France or Germany?
Answer: Germany

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: If species A population decrease, would the population of species B increase or decrease?
Answer: increase

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: If species A population stay stable, would the population of species B increase or not increase?
Answer: not increase

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: If species B population increase, would species C population increase or decrease?
Answer: decrease

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: If species B population decrease, would species C population increase or decrease?
Answer: increase

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: If species A population decrease, would species C population increase or decrease?
Answer: decrease

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: If species A population increase, would species C population increase or decrease?
Answer: increase

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: If species A population decrease, would it affect the ecosystem positively or negatively?
Answer: negatively

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: If species B population increase, would it affect the ecosystem positively or negatively?
Answer: negatively

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: If species C population decrease, would it affect the ecosystem positively or negatively?
Answer: negatively

Situation: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem.

Question: Which species can be regarded as the keystone species, species A, species B, or species C?
Answer: species A