Ecology I

What would happen if the decomposers were removed from an ecosystem?

• The dead matter would pile up.
• The nutrients in the dead matter would not get recycled.
• The ecosystem would eventually run out of nutrients and elements because they would be trapped in the dead organisms.
• All of the answers are correct.

How long are food chains?

• four steps long
• three steps long
• it varies with day length
• it varies with ecosystem

One of the nutrient cycles moves from an atmospheric gaseous form to the soil through both abiotic and biotic processes, moves through the food web, then is returned to the soil or to the atmosphere.  Which cycle fits this description?

• carbon
• nitrogen
• phosphorus
• water

Which of the following is the ultimate source of energy for this pyramid?

• grass
• heat
• sunlight
• water

Which of the following allows the flow of energy through an ecosystem to happen?

• abiotic factors
• condensation
• evaporation
• predation

Imagine that a certain animal becomes extinct due to human activity.  What effect, if any, would this have on the animal’s predators?

• The predators’ population would increase due to the increase in other organisms living.
• The predators’ population would not change.
• The predators would be excited about having one less animal to chase.
• The predators’ population would probably decrease due to the lack of food.

Refer to the illustration.  The diagram, which shows how energy moves through an ecosystem, is called a

• habitat net
• food chain
• trophic level
• food web

Cougars are predators that often eat weakened or diseased animals. This is a description of the ____ of cougars.

• habitat
• community
• niche
• none of these

In this energy pyramid, which level has the smallest number of organisms?

• fox
• birds
• grasshoppers
• grass

Which is the beginning source of energy driving the biogeochemical cycles?

• water
• carbohydrates
• chloroplasts
• sunlight