How Ecosystems Change - Skills Practice #2

In Africa, as the crocodile lies with its mouth open, the plover, or crocodile bird, flies into its mouth and feeds on bits of meat stuck in the crocodile’s teeth. The crocodile does not harm the plover. The plover gets a meal and the crocodile gets his teeth cleaned. What conclusions might be drawn regarding the dynamics of this relationship?

• It is a mutualistic relationship because both animals benefit; neither animal is harmed.

• It is a symbiotic relationship because the plover benefits from the meat in the crocodile's teeth.

• The crocodile is a predator. The plover is a parasite. There are two relationships illustrated by this dynamic.

• It is an example of commensalism because the plover benefits from the relationship while the crocodile is neither helped or harmed.

Because they are so diverse, coral reefs are often called the rainforests of the sea. Which is not a biotic factor in the coral reef?

• algae

• coral

• rocks

• sponges

A deer is nibbling clover while a frog watches from atop a nearby rock. What is the ONLY abiotic factor mentioned in the sentence?

• clover

• deer

• frog

• rock

If we assume that, in the African savanna, the predator population remains constant, what other, nonmobile, factor would influence the antelope population?

• human presence

• other antelope

• available grass

• competition from zebra

Pick any habitat and model a food web to illustrate the flow of food energy. Those were your teacher’s instructions. You created a beautiful drawing as your model, as seen here, but your teacher commented that it was not accurate. What is an important limitation of your food web?

• Your model is not in color.

• It is not a web; it is a chain.

• The scale of your drawings are inaccurate.

• It does not show how similar organisms use energy.

As resources, such as food and space, become depleted, the bacterial population density will decrease. From the choices offered, during which month would resources be the most limited?

• March

• May

• July

• September

The tundra and taiga have unique characteristics which help distinguish them from each other. Which of these physical factors led to the differences found in these biomes?

• The tundra is colder and receives less rainfall than the taiga.

• The tundra is colder and receives more rainfall than the taiga.

• The tundra is warmer and receives less rainfall than the taiga.

• The tundra is warmer and receives more rainfall than the taiga.

Two abiotic (Physical rather than biological; not derived from living organisms.) factors of an environment COULD include

• birds and bees.

• snails and snowfall.

• mosquitoes and mushrooms.

• clouds and carbon dioxide.

If the bird population is directly proportional to the average monthly temperature, which month would have the LOWEST temperature?

• August

• December

• January

• October

A species of rabbit lives in a meadow where grass plants are readily available during summer months. The rabbits do not stray far from the meadow because the plants supply food and protection from predators. One summer, a fire destroys the plants in the meadow. As a result of the absence of plants in the meadow, the rabbit population will probably

• decrease in size.

• increase and flourish.

• increase reproduction.

• switch to a different type of food.