Unit 2 Ecology Exam

Phytoplankton growth is highest near the ocean surface because of which factor?

• Colder temperatures

• Increased sunlight

• Increased salinity

• Decreased carbon dioxide

Compared to the open ocean, coastal waters often have increased growth of phytoplankton and other producers. What is the primary reason for this difference?

• Higher temperature

• Greater sunlight exposure

• More nutrient input from land

• Increased oxygen levels

Burning fossil fuels impacts the global carbon cycle by:

• Storing additional carbon compounds

• Accelerating the speed of the cycle

• Releasing carbon into the atmosphere

• Removing carbon from the cycle

Ecosystem stability can be disrupted by major extinction events. What is the most frequent cause of mass extinctions on Earth?

• Widespread disease

• Invasive species

• Gradual climate change

• Rapid climate change

Which action would likely be most effective at slowing climate change and reducing its ecological impacts?

• Using less synthetic fertilizer

• Capturing sulfur from emissions

• Banning ozone-depleting chemicals

• Transitioning to renewable energy sources

If a mouse was placed in a closed box with sufficient air, water and food but no plants, what would most likely cause its death after a period of time?

• High carbon dioxide levels without plant photosynthesis

• Depletion of carbon dioxide without plant respiration

• Nitrogen buildup in water without algae

• Excess nitrogen in air without nitrogen-fixing bacteria

Bruce claims the water cycle functions without an energy source. Which evidence best counters this claim?

• The sun provides energy for precipitation.

• The sun enables evaporation and transpiration.

• Organisms use energy to obtain and move water.

• Photosynthesis requires solar energy.

What factor enables plant growth in estuary environments despite challenges?

• Rocky, unstable soil

• Colder water temperatures

• Exposure to direct sunlight

• Toleration of salinity

Atmospheric carbon dioxide shows an overall increasing trend annually. However, slight decreases may be observed in some northern hemisphere locations during certain months. What is the most likely explanation for these temporary dips?

• Increased cellular respiration in summer

• Decreased cellular respiration in summer

• Increased photosynthesis in summer

• Increased nitrogen fixation in summer

Most food webs omit decomposers. How would their absence impact an ecosystem?

• All populations would eventually decline.

• Only small plant populations would be reduced.

• The ecosystem would function normally.

• Feeding relationships would be altered.