CA #2 (Biology 1)

1. Asian carp are an invasive species of fish. These large fish eat up to 40% of their body weight per day by feeding on phytoplankton. The carp also reproduce quickly. If these fish were to enter Lake Erie, how would the Presque Isle coastal ecosystem MOST LIKELY be affected?

• A. Producers in the ecosystem would grow at a faster rate, and smaller fish such as yellow perch would thrive.
• B. The invasive fish would prey on mollusks such as mussels, but native fish species would quickly eat the invasive fish.
• C. Consumers in the higher trophic levels would suffer stress, but crustaceans such as amphipods would be unaffected.
• D. Most consumers in the ecosystem would face a shortage of food, and larger fish, such as walleye, would be unable to thrive.

2. A farmer observed that an increase in a field’s soil nitrogen content was followed by an increase in producer productivity. What does this observation most likely indicate about the relationship between nitrogen and the producers in the field?

• A. Nitrogen was a biotic factor.
• B. Nitrogen was a limiting factor.
• C. Nitrogen became a surplus resource.
• D. Nitrogen became a selection pressure.

3. Most of the water on Earth is located in the oceans and has a salinity of about 3.5%. Which statement best explains why rain is fresh water and has a very low salinity?

• A. When water precipitates from oceans, most of the salt remains in the oceans.
• B. When water evaporates from oceans, most of the salt remains in the oceans.
• C. When water precipitates from clouds, most of the salt remains in the clouds.
• D. When water evaporates from clouds, most of the salt remains in the clouds.

4. Agricultural runoff can carry fertilizers into lakes and streams. This runoff can cause algae populations to greatly increase. Which effect does this change in the algae population sizes MOST LIKELY have on affected lakes and streams?

• A. An increase in water level
• B. An increase in water clarity
• C. A reduction in dissolved oxygen needed by fish and shellfish
• D. a reduction in temperature variations near the water’s surface

5. Which statement correctly describes how nitrogen in the soil returns to the atmosphere?

• A. Soil bacteria convert nitrates into nitrogen gas.
• Decomposers directly convert ammonium into nitrogen gas.
• Plants assimilate nitrites and convert them into nitrogen gas.
• Nitrogen-fixing bacteria in plant roots convert nitrates into nitrogen gas.

6. Ash from a volcanic eruption decreases the amount of available solar energy for a region. Which statement describes how a decrease in available sunlight will most likely affect ecosystems of this region?

• A. Producer populations will decrease, causing a decrease in consumer populations.
• B. Producer populations will decrease, causing an increase in consumer populations.
• C. Decomposer populations will increase, causing a decrease in consumer populations.
• D. Decomposer populations will increase, causing an increase in consumer populations.

7. Which of the following is the best definition of pollution

• A. A natural resource that humans overuse
• B. A human activity that destroys habitats
• C. A harmful substance released into the environment
• D. A species that humans introduce into an ecosystem

8. The graph shows the concentrations of atmospheric carbon dioxide measured over 50 years at an observatory in Hawaii. The graphed line indicates an overall upward trend with fluctuations occurring yearly. Which BEST explains these yearly fluctuations in carbon dioxide concentration?

• A. More carbon dioxide is dissolved into oceans during warm summer months.
• B. More carbon dioxide is released from oceans to the atmosphere during cold winter months.
• C. The process of photosynthesis removes more carbon dioxide from the atmosphere as more vegetation grows during the summer.
• D. Algal photosynthesis removes more carbon dioxide from the atmosphere as lack of foliage during winter allows more light to reach lakes and rivers.

9. Increases in which of the following can increase population size?

• A. Emigration and birth rate
• B. Emigration and death rate
• C. Immigration and birth rate
• D. Immigration and death rate

10. In some parts of the world rain forests are being cut down to make land available for farms. How does this loss of these trees affect carbon dioxide and oxygen in the atmosphere?

• A. It increases both carbon dioxide and oxygen
• B. It decreases both carbon dioxide and oxygen
• C. It increases carbon dioxide and decreases oxygen
• D. It decreases carbon dioxide and increases oxygen