Ecology Unit Review (Questions From The 2004 Md Hsa)

1. Scientists classify humans as omnivores, based on their teeth. As omnivores, humans eat _____.

Only fungi

Mostly plants and animals

Only animals

Mostly bacteria and fungi

Think of the definition of an omnivore. That's all there is to it!

Explanation

Think of the definition of an omnivore. That's all there is to it!

2. Ladybugs eat aphids, which are a source of protein for the ladybugs. Which of these terms best describes the relationship between the ladybugs and the aphids?

Mutualism

Parasite–host

Predator–prey

Commensalism

Ladybugs kill and eat aphids. This makes the ladybug a predator.

Explanation

Ladybugs kill and eat aphids. This makes the ladybug a predator.

3. As you move up the trophic levels from producers to second order consumers, you would expect the see the amount of available energy _____________.

Decrease

Increase

Increase, then decrease

There is no way to tell

There is less energy available to each level of consumer because some of the energy is converted ("used") by the organisms in the previous trophic level.

Explanation

There is less energy available to each level of consumer because some of the energy is converted ("used") by the organisms in the previous trophic level.

4.

Horseshoe crabs are used by fisherman for bait. If the horseshoe crab population were reduced by overfishing, which of these groups of organisms would most likely decrease in number?

Plankton, razor clams, and loggerhead turtles

Sanderlings, loggerhead turtles, and striped bass

Grackles, plankton, and diamondback terrapin

Striped bass, sanderlings, and razor clams

They would all lose their main source of food.

Explanation

They would all lose their main source of food.

5. Which of these describes the role of the sanderling in the marine food web below

?

Producer

Herbivore

Carnivore

Omnivore

The arrow pointing to the sanderling from the horseshoe crab shows that the sanderling consumes the crab for food. There are no arrows showing that the sanderling consumers any plants. Therefore, it is a meat-eater, or a carnivore.

Explanation

The arrow pointing to the sanderling from the horseshoe crab shows that the sanderling consumes the crab for food. There are no arrows showing that the sanderling consumers any plants. Therefore, it is a meat-eater, or a carnivore.

6. Aphids are insects that feed on fluids from the stems of plants. After the aphids ingest the plant fluids, they excrete a liquid called honeydew. Some species of ants protect aphids from predators. The ants benefit by feeding on the honeydew produced by the aphids. Which of these terms best describes the relationship between the aphids and the ants?

Mutualism

Parasite–host

Predator–prey

Commensalism

Both organisms benefit. The aphid gets free protection by the ant and the ant gets food.

Explanation

Both organisms benefit. The aphid gets free protection by the ant and the ant gets food.

7.

How would the populations of other organisms in the energy pyramid be affected if the population of sea urchins suddenly decreased?

Both the kelp and the sheephead populations would increase.

Both the kelp and the sheephead populations would decrease.

The kelp population would decrease, and the sheephead population would increase.

The kelp population would increase, and the sheephead population would decrease.

Kelp increases because there are fewer sea urchins eating it. Sheephead population decreases because there are fewer urchins for food.

Explanation

Kelp increases because there are fewer sea urchins eating it. Sheephead population decreases because there are fewer urchins for food.

8. A student used a microscope to observe several protists. The student sketched the protists and recorded their magnifications. The drawings and measurements are shown below.

Which of these protists is the largest?

Difflugia

Stentor

Euglena

Paramecium

A and B are magnified only 4 times, so they are larger than C and D, which had to be magnified 10 times to be seen clearly. Between A and B, A (Difflugia) appears the largest.

Explanation

A and B are magnified only 4 times, so they are larger than C and D, which had to be magnified 10 times to be seen clearly. Between A and B, A (Difflugia) appears the largest.

9. On Earth, water cycles through the atmosphere, oceans, land, and organisms. By what process does most of the water in plants return to the environment?

Evaporation from the roots

Condensation on the leaves

Evaporation from the leaves

Diffusion from the roots

Roots are used to absorb water, not to release it into the environment, so a and d are incorrect. Condensation on leaves would bring water to the plant, but not return it to the atmosphpere. Evaporation from leaves is the only correct choice. This is also called transpiration.

Explanation

Roots are used to absorb water, not to release it into the environment, so a and d are incorrect. Condensation on leaves would bring water to the plant, but not return it to the atmosphpere. Evaporation from leaves is the only correct choice. This is also called transpiration.

10.

What is the lowest level of the energy pyramid that contains carnivores?

Level 1

Level 2

Level 3

Level 4

The lowest level of the energy pyramid that contains carnivores is Level 3. In an energy pyramid, each level represents a trophic level, with producers at the bottom and top-level predators at the top. Carnivores are usually found at the third trophic level, as they feed on herbivores that are at the second trophic level. This is because energy is transferred from one trophic level to another, and the energy available decreases as it moves up the pyramid. Therefore, carnivores are typically found at a higher trophic level than herbivores.

Explanation

The lowest level of the energy pyramid that contains carnivores is Level 3. In an energy pyramid, each level represents a trophic level, with producers at the bottom and top-level predators at the top. Carnivores are usually found at the third trophic level, as they feed on herbivores that are at the second trophic level. This is because energy is transferred from one trophic level to another, and the energy available decreases as it moves up the pyramid. Therefore, carnivores are typically found at a higher trophic level than herbivores.