Unit 9 Lesson 3 Self-Check Patterns of Interaction

Which statements describe the feeding interaction between frogs and insects? Circle all that apply.

• The frog is a predator.

• The interaction is mutualistic.

• The frog is a parasite.

• The number of insects can influence the number of frogs in the ecosystem.

If a drought causes insect populations to decrease, the frog population will likely (a)   . If populations of birds that eat insects decrease, the frog population will likely (b)   .

• decrease
• increase
• remain stable

• disappear

Hundreds of pounds of barnacles may be attached to the surface of whales at a given time. Unnoticed by the whale, barnacles avoid ​ (a)   and filter plankton from ocean water while the whales feed. This interaction is an example of ​ (b)   , where the barnacles ​ (c)   while the whale is unaffected.

• benefit
• are unaffected
• are harmed
• commensalism
• mutualism
• parasitism
• predators
• prey

Whale lice live on the surface of whales. They are very small, and they feed on whale skin. Which statement best describes the relationship between lice and barnacles?

• They have a predator-prey relationship.

• They are both whale parasites.

• They compete for food resources.

• They do not compete for food resources, but may compete for space on a whale.

Atlantic salmon migrate to rivers in New England to reproduce and to the coast of Greenland to feed. Which of these scenarios could cause a decrease in salmon populations due to competition? Circle all that apply.

• Abundant food resources in Greenland

• Limited food resources in Greenland

• Increased predation by birds

• Limited space for reproduction in New England rivers

In a predator-prey relationship, the population sizes of the two species are interconnected. When the prey population ​ (a)   , the predator population has more food available, which allows it to ​ (b)   . However, as the predator population grows, it consumes more prey, causing the prey population to ​ (c)   . Eventually, the reduced prey population cannot support the large predator population, leading to a ​ (d)   in predator numbers. This cyclical pattern continues over time, creating fluctuations in both populations.

• increases
• grow
• decline
• decrease
• stabilize

Predators and parasites both depend on other species, but their effects differ. Predators usually ​ (a)   prey quickly, while parasites ​ (b)   hosts slowly, often keeping them alive. Predation is a ​ (c)   interaction, whereas parasitism typically lasts a ​ (d)   . Unlike predators, parasites often rely on ​ (e)   host to survive.

• kill
• harm
• benefit
• short-term
• long-term
• long time
• one
• many

When resources are abundant in an ecosystem, competition between organisms ​ (a)   . This is because there is ​ (b)   to share, so species ​ ​ (c)   fight as much for survival. However, if resources become ​ (d)   , competition will grow stronger.

• decreases
• increases
• more
• less
• do not need to
• must
• scarce
• plentiful