Ecosystem

1. Which event illustrates the interaction of two biotic factors within the environment?

• A gypsy moth caterpillar eats the leaves of an apple tree

• The temperature of water affects its oxygen level.

• The lamprey eel survives by taking shelter in an underwater cave

• The low light intensity of the forest affects the growth of pine trees.

Ostriches and gazelles feed near one another.  They both watch for predators in different ways and alert each other to danger. This is an example of what?

• Mutualism

• Parasitism

• Commensalism

• Predation

Which is an example of a biotic factor that would limit the size of a deer herd?

• Population of predators

• Lack of oxygen at high altitudes

• Heavy winter snowfalls

• Severe summer drought

Because vultures feed mainly on organisms that they have not killed, they are known as what type of organism?

• Predators

• Autotrophs

• Scavengers

• Omnivores

Which situation would result in the greatest increase in the human population?

• Increased infant mortality and decreased death rate

• Decreased death rate and increased birth rate

• Decreased birth rate and increased death rate

• Increased birth rate and increased infant mortality

A snake eats a frog that has eaten an insect that fed on a plant.  What level of organism is the frog?

• Secondary consumer

• Producer

• Tertiary Consumer

• Primary consumer

Which of the following best explains why producers are always at the beginning of a food chain?

• Producers are larger than consumers.

• Consumers are eaten by a variety of producers.

• Producers are found in fewer numbers than consumers.

• Producers convert light energy into usable energy.

Looking at the food web to the right, What would most likely decrease the mouse population?

• A decrease in the snake and hawk popluation

• An increase in the frog and tree population

• An increase in the number of decomposers

• A decrease in the amount of available sunlight

Why do ecosystems usually contain only a few trophic levels?

• because only 50% of the energy harnessed is passed to the next level

• because only 5% of the energy harnessed is passed to the next level

• because only 10% of the energy harnessed is passed to the next level

• because only 100% of the energy harnessed is passed to the next level

How do decomposers contribute to a food web cycle?

• acts as a carnivore

• recycles dead organisms and nutrients and makes soil

• does photosynthesis

• makes glucose for other organisms