The Nitrogen Cycle and Energy Flow in Ecosystems

This comprehensive diagram provides a detailed explanation of the nitrogen cycle, carbon cycle, and energy flow in ecosystems, along with ecological pyramids. It serves as an excellent resource for students studying these fundamental ecological concepts.

The Nitrogen Cycle

The diagram illustrates the complex process of the nitrogen cycle, showing how nitrogen moves through different forms in the environment.

Highlight: Plants can only absorb nitrogen in the form of nitrates, making them dependent on nitrogen-fixing bacteria to convert atmospheric nitrogen into usable forms in the soil.

Key steps in the nitrogen cycle include:

1. Nitrogen fixation by bacteria
2. Absorption of nitrates by plants
3. Decomposition of organic matter
4. Denitrification

Example: The Haber Process is mentioned as an industrial method to convert nitrogen into ammonia for fertilizer production.

The Carbon Cycle

The carbon cycle is briefly explained, highlighting the following processes:

1. Photosynthesis removing carbon dioxide from the atmosphere
2. Carbon transfer through food chains
3. Respiration and combustion releasing carbon dioxide
4. Decomposition of organic matter

Energy Flow Through Ecosystems

The diagram emphasizes the concept of energy flow in ecosystems, explaining how energy is transferred and lost at each trophic level.

Highlight: Only about 10% of energy is passed on at each trophic level, limiting food chains to generally no more than 5 trophic levels.

Ecological Pyramids

The document introduces different types of ecological pyramids:

1. Pyramids of numbers
2. Pyramids of biomass
3. Pyramids of energy

Definition: Biomass is defined as the dry mass of a plant or animal species.

Vocabulary: Trophic levels are explained, including producers, primary consumers, secondary consumers, and tertiary consumers.

The diagram provides visual representations of these pyramids, noting that while pyramids of energy are always triangle-shaped, pyramids of numbers may not always follow this pattern.