Ecology

Humans increase carbon dioxide (CO2) in the atmosphere, and contribute to the carbon cycle by

• combustion from driving cars.

• planting trees to improve photosynthesis.

• conserving energy with alternative energies.

• using more solar power electricity.

Nitrogen in the air must be "fixed" before it can be used by plants. Atmospheric nitrogen is "fixed" by

• plants.

• bacteria

• bacteria and insects.

• bacteria and fungi (decomposers).

When deforestation (cutting down trees) occurs in an area, what immediate effect does this have on the water cycle?

• More water is returned to the atmosphere by transpiration.

• There is less runoff water, but more transpiration.

• More photosynthesis occurs, and CO2 begins decreasing.

• Less is returned to the air by transpiration.

A group of eagles living around Lake Tahoe would be considered a(n) .

• abiotic factor

• population

• community

• ecosystem

Fish, their predators, and the water, sunlight, and plants that they rely on would be considered a(n)

• abiotic factor

• population

• community

• ecosystem

Which of the following is NOT a characteristic of a living thing?

• moves around

• uses energy for metabolism

• contains cells

• reproduces

Organisms, such as plants or phytoplankton that carry out photosynthesis, would cause a decrease of which gas in the atmosphere?

• Oxygen

• Carbon dioxide

• Water

• Ozone

In the carbon cycle, decomposers return carbon to the soil. Which of the following is NOT something that decomposers can break down?

• Waste products like urine or feces

• The bodies of dead plants and animals.

• Carbon dioxide found in the air

• Scraps of discarded food

Bacteria are involved in many steps of the biogeochemical cycles. Which of the following steps is bacteria NOT involved?

• Decomposition

• Transpiration

• Nitrification

• Nitrogen fixation

The main result of photosynthesis is

• decreased atmospheric nitrogen.

• CO2 is removed and captured by plants.

• absorbing nitrogen for the plant to use.

• global warming caused by CO2 being removed.