Ecology Review Level 2

Organisms that eat cows obtain less energy from the cow since cows:

• Pass on a lot of energy to offspring

• Convert solar energy into food

• Store energy in milk

• Use energy for cellular respiration

The diagram represents an energy pyramid. At each successive level from A to D the amount of energy-

• Increases only

• Decreases only

• Increases then decreases

• Decreases then increases

Which role of protists and fungi has the most positive effect on maintaining the plant population in a ecosystem?

• Protists and fungi are a major source of food for animals.

• Protists produce oxygen for the plants.

• Protists and fungi decompose organic matter and return nutrients to the soil.

• Protists and fungi found in the gut of animals aids in digestion.

A biomass picture of an ecosystem is shown. Which statement provides the best explanation for the difference in biomass of organisms found at each trophic level.

• Organisms at higher trophic levels have less energy available to them than organisms at lower trophic levels.

• Organisms at higher trophic levels require smaller habitats than organisms at lower trophic levels.

• Organisms at lower trophic levels provide less energy than organisms at higher trophic levels.

• Organisms at lower trophic levels outcompete organisms at higher trophic levels.

A new species of snake was introduced to a tropical region. Scientists then noticed a steady decline in the presence of field mice and an increase in the number of snakes. Which of these is the most likely explanation about why the population size of each animal changed?

• the snakes introduced to the region dominated the habitat, forcing the mice to find another place to live.

• the mice became prey to the introduced snakes, allowing the snake population to increase but decreasing the mice population.

• the snakes introduced to the region competed with the mice for food, allowing the snake population to increase but decreasing the mice population.

• the people in the surrounding areas set traps that killed the mice, allowing the snakes to live without any predators and therefore to increase in number.

Grasses --> Crickets --> Field Mice --> Hawks

For the food chain above, which of the following changes would have the most severe consequences?

• drastic decrease in the rainfall leading to a drought

• the poaching of predators, such as hawks, by hunters

• the introduction of a second predator that eats field mice

• a parasitic infestation that reduces the number of crickets