HS-LS2-4. Use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem.

Ecosystems are dynamic systems where matter and energy flow between organisms. Matter cycles through the ecosystem as atoms and molecules are reused, while energy flows through the ecosystem, primarily entering through sunlight and being transferred through different organisms in the food chain. Understanding these processes is essential to grasping how ecosystems function. This review will cover key concepts related to the cycling of matter and the flow of energy, focusing on how mathematical models, such as energy pyramids, help us understand these processes.

Main Concepts

Cycling of Matter: In an ecosystem, matter is recycled. Essential elements like carbon, oxygen, hydrogen, and nitrogen move through different parts of the ecosystem, including plants, animals, and the atmosphere. These elements are conserved as they cycle through various forms, such as carbon dioxide, water, and organic molecules.

Flow of Energy: Energy flows through an ecosystem starting with sunlight, which is captured by plants through photosynthesis. This energy is then transferred to other organisms when they consume plants or other animals. Unlike matter, energy is not recycled but instead flows in one direction, eventually being lost as heat.

Energy Pyramids: An energy pyramid is a graphical model that shows the distribution of energy among trophic levels in an ecosystem. The base of the pyramid represents the primary producers (like plants), which have the most energy. As energy moves up the pyramid to primary consumers (herbivores) and then to secondary and tertiary consumers (carnivores), the amount of available energy decreases.

Conservation of Matter and Energy: Matter and energy are conserved in an ecosystem. This means that the total amount of matter and energy remains constant, even as they change forms and move between organisms. For example, the carbon in a plant might become part of an animal’s body when the plant is eaten, and the energy stored in the plant’s sugars is transferred to the animal.

Mathematical Models: Mathematical models, such as energy pyramids or biomass pyramids, help us visualize and understand the flow of energy and the cycling of matter. These models can show how much energy is transferred from one trophic level to the next and how much is lost, typically as heat.

Review Questions and Answers

1. What does the cycling of matter in an ecosystem refer to?

The cycling of matter refers to the continuous movement and reuse of elements like carbon, oxygen, hydrogen, and nitrogen within the ecosystem.

2. How does energy flow through an ecosystem?

Energy flows through an ecosystem beginning with sunlight, which is captured by plants. This energy is then transferred through different organisms in the food chain and is eventually lost as heat.

3. What is an energy pyramid?

An energy pyramid is a graphical representation that shows the amount of energy available at each trophic level in an ecosystem. The energy decreases as it moves up the pyramid from producers to consumers.

4. Why is energy lost as it moves up the energy pyramid?

Energy is lost as it moves up the energy pyramid because organisms use some of the energy for their life processes, and some energy is lost as heat.

5. What does the conservation of matter mean in an ecosystem?

The conservation of matter means that the total amount of matter remains constant in an ecosystem, even as it changes forms and moves through different parts of the ecosystem.

6. How do mathematical models help us understand ecosystems?

Mathematical models, like energy and biomass pyramids, help us visualize and quantify the flow of energy and the cycling of matter in ecosystems.

7. What are trophic levels?

Trophic levels are the different levels in a food chain, representing the position an organism occupies, such as a primary producer, primary consumer, or secondary consumer.

8. Why is the base of an energy pyramid the largest?

The base of an energy pyramid is the largest because it represents the primary producers, which have the most energy available to support the rest of the ecosystem.

9. What happens to the atoms of carbon in a plant when it is eaten by an animal?

The atoms of carbon in the plant become part of the animal’s body, showing how matter is conserved and cycled through the ecosystem.

10. How does the energy transfer differ between trophic levels?

Energy transfer between trophic levels is inefficient, with only about 10% of the energy from one level being passed to the next, while the rest is lost as heat.

*continue your studies by accessing another review sheet below*

 

Disclaimer: The information provided is intended to serve as a study guide based on a contextual analysis of the NGSS standards for the Life Science Biology assessment. These study guides should be used as a supplement to your overall study strategy, and their alignment to the actual test format is not guaranteed. We recommend that you consult with your instructor for additional guidance on exam preparation.