Unit 12: Interactions within Ecosystems

Question 1

Describe a predator-prey relationship.

Answer 1

An animal that lives by killing and eating other animals is called a predator.
An animal that is killed and eaten by another is called a prey.
In a predator-prey relationship, the predator feeds on the prey.

Question 2

Describe parasitism.

Answer 2

Parasitism is a relationship between two organisms in which one (parasite) benefits at the expense of the other (host). A parasite normally does some harm to its host.

Question 3

Describe mutualism.

Answer 3

Mutualism is a relationship between two organisms in which both organisms benefit from each other.

Question 4

Describe commensalism.

Answer 4

Commensalism is a relationship between individuals of two species in which one species obtains food or other benefits from the other without either harming or benefitting the latter. Basically, one species benefits and the other is unaffected.

Question 5

Describe the transfer of energy.

Answer 5

At each stage, only about 10% of energy is transferred. Thus, the last organism in the food chain receives the least amount of energy from the sun.

Question 6

Why are there more [type of predator] than [type of prey] in this habitat?

Answer 6

At every stage, a large amount (almost 90%) of energy is lost as heat energy, thus there is not enough energy to sustain higher levels of the food web/chain.