13A) Ecological Relationships

A hawk attacks and kills a mole, consuming it for its meal. What type of ecological interaction exists between the hawk and the mole?

• Mutualism

• Parasitism

• Commensalism

• Predation

Answer explanation

The answer is predation because the hawk (predator) consumes the mole (prey)

Two plants grow beside one another trying to access limited available sunlight. What ecological interaction describes the relationship between the two plants?

• Mutualism

• Herbivory

• Competition

• Commensalism

Answer explanation

Competition arises when species compete for a limited supply of resources, such as food, mates, water, or space.

Competition occurs between members of the same species (intraspecific competition) and between different species (interspecific competition)

A hermit crab discovers an abandoned snail shell and makes it home inside the shell. Which type of ecological relationship is illustrated by the hermit crab and the snail?

• Parasitism

• Competition

• Commensalism

• Mutualism

Answer explanation

The answer is commensalism which means one organism benefits (hermit crab) and the other is unaffected (snail).

Since the snail shell is abandoned, the snail is not harmed by the hermit crab's use of the shell.

Animals that break down complex compounds and dead tissues are ______.

• Producers

• Scavengers

• Decomposers

• Parasites

In the savannah, a pride of lions stalks antelope. When they spot a weak one, they work together to kill it. Sometimes, hyenas appear and attempt to steal the carcass. This relationship between the lions and hyenas can best be described as:

• Predation

• Competition

• Cooperation

• Mutualism

Answer explanation

The answer is competition because the lions and hyenas are competing over the carcass.

Animals that feed only on dead organisms are _______.

• Decomposers

• Scavengers

• Parasites

• Producers

Which of these best demonstrates mutualism between certain types of bacteria and humans?

• Bacteria in improperly prepared food are consumed by humans, causing food poisoning.

• Bacteria become resistant to antibacterial medication that humans use for treatment.

• Intestinal bacteria obtain nutrients from the gut and produce vitamin K used by humans.

• Invasive bacteria in an area of injury produce toxins that damage healthy tissues of the human body.

Some relationships between different organisms are shown in the table. Which table correctly identifies each type of interaction described?

• 
• 
• 
• 

What happens as a result of scarcity of resources?

• Drought

• Competition

• Extinction

• Overabundance

In any environment or ecosystem, organisms can have several different types of relationships. Three types of relationships are described in the table. Which of these correctly describes the relationship between the organisms?

• X: commensalism

  Y: parasitism

  Z: mutualism

• X: commensalism

  Y: mutualism

  Z: parasitism

• X: parasitism

  Y: commensalism

  Z: mutualism

• X: mutualism

  Y: parasitism

  Z: commensalism