Ecosystem Material Cycles

Which process is responsible for the conversion of ammonia into nitrates in the nitrogen cycle?

What role do decomposers play in the ecosystem?

How does water vapor return to Earth in the water cycle?

What is the primary source of nitrogen for plants?

What process involves the conversion of nitrogen gas into ammonia?

In an ecosystem, what do autotrophs primarily do?

Which of the following best describes how carbon cycles through the environment?

What two factors are primarily cycled in the carbon-oxygen cycle?

What is one of the primary roles of bacteria in soil within the nitrogen cycle?

Which organisms are primarily responsible for breaking down dead plants and animals in the ecosystem?

Cycles of Materials

Ecosystems are in a state of approximate equilibrium, with cyclic changes in materials.
Materials like carbon, oxygen, hydrogen, and nitrogen must be recycled and reused between the living and nonliving environment.

Carbon-Oxygen Cycle

Carbon dioxide and water molecules are used in photosynthesis to form energy-rich organic compounds.
These organic compounds are returned to the environment when the energy is eventually released by cells.

Water Cycle

Water moves between the Earth's surface and atmosphere.
Liquid water turns into water vapor through evaporation and transpiration.
Water vapor gathers in clouds and returns as precipitation through condensation.

Nitrogen Cycle

Plants obtain nitrogen from the soil.
Nitrogen is essential for living things as it is part of the amino acids and proteins (-NH2).
Animals consume plants to get nitrogen.
Decomposers (bacteria and fungi) recycle dead plants, animals, and waste in the soil.
Nitrifying bacteria convert ammonia into nitrates.
Nitrogen-fixing bacteria convert nitrogen gas into ammonia.
Denitrifying bacteria convert nitrates into nitrogen gas.

Bacteria In Ecosystems

Bacteria play a crucial role in the flow of materials through ecosystems.
Decomposers like bacteria break down organic matter, releasing nutrients back into the ecosystem.

Soil Bacteria

When animals excrete nitrogenous wastes into the soil, certain soil bacteria convert these wastes into nitrates.
These soil bacteria are decomposers, consuming and breaking down organic matter.

Explore the vital cycles of materials in ecosystems, including the carbon-oxygen, water, and nitrogen cycles. Understand how these elements interact between the living and nonliving environments and their importance to life on Earth.