Ecosystems: Energy Flow & Biogeochemical Cycles

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Questions and Answers

Which of the following is NOT a part of the Earth's spheres where elements are recycled?

Photosphere (correct)

Biosphere

Atmosphere

Hydrosphere

What is the purpose of nitrogen-fixing bacteria in the nitrogen cycle?

To produce methane

To convert nitrate into nitrogen gas

To break down organic matter

To convert nitrogen gas into nitrate (correct)

What is the byproduct of methanogenesis in anaerobic respiration?

Carbon dioxide

Oxygen

Nitrate

Methane (correct)

What is the role of denitrifying bacteria in the nitrogen cycle?

To convert nitrate into nitrogen gas Signup and view all the answers

Where are anaerobic bacteria found that produce methane?

In the digestive tracts of ruminants Signup and view all the answers

What is the significance of methane in the context of the environment?

It is a potent greenhouse gas Signup and view all the answers

What is the main reason for the limitation of food chains to 4-6 trophic levels?

There is a decrease of available energy at successively higher trophic levels. Signup and view all the answers

What percentage of energy is typically transferred from one trophic level to the next?

10% Signup and view all the answers

Why can't biomass and energy pyramids be inverted?

Because the biomass decreases at each successive trophic level. Signup and view all the answers

What are the 5 chemical elements common in organic matter that are a part of essential nutrients?

C, H, N, O, and P Signup and view all the answers

What is the name of the cycles that involve the movement of chemical elements?

Biogeochemical Cycles Signup and view all the answers

What is the term for the process by which energy is lost as heat from cellular respiration?

Cellular Respiration Signup and view all the answers

What is the direction of energy flow in ecosystems?

One-way Signup and view all the answers

What is the source of energy that moves through an ecosystem?

The sun Signup and view all the answers

What is the term for the amount of biomass produced minus the amount of energy lost to cellular respiration?

Net Primary Productivity Signup and view all the answers

What is the process by which energy is converted into chemical energy in organisms?

Photosynthesis Signup and view all the answers

What is the law that states energy cannot be created or destroyed, only transformed?

Law of the Conservation of Energy Signup and view all the answers

What is the term for the total amount of biomass produced and energy used in cellular respiration?

Gross Primary Productivity Signup and view all the answers

Study Notes

Earth's Spheres and Cycles

Earth's biological, geological, and chemical processes involve the recycling of matter in four spheres: biosphere (organisms), hydrosphere (water), atmosphere (air), and lithosphere/geosphere (soil and rocks).
Matter is conserved and cycled in both biotic and abiotic parts of an ecosystem through four major cycles: carbon (C), water (H2O), nitrogen (N), and phosphorus (P).

Biogeochemical Cycles

The nitrogen cycle involves anaerobic bacteria, nitrogen-fixing bacteria, and denitrifying bacteria to convert nitrogen gas (N2) into nitrate (NO3-) for plant growth.
Anaerobic bacteria also play a role in the carbon cycle through methanogenesis, converting CO2 to methane (CH4) and producing ATP.

Energy Flow in Ecosystems

Energy is transferred from one trophic level to the next in a food chain, but not all consumed biomass is transformed into digested energy.
Approximately 10% of energy is transferred between trophic levels, with a range of 25%.
Energy transfer varies depending on environmental factors like aquatic vs terrestrial ecosystems, temperature, and complexity of the food web.

Biogeochemical Nutrient Cycles

Five chemical elements are essential nutrients in organic matter: C, H, N, O, and P.

Energy and Biomass

Energy flow and cycles of matter occur within organisms through anaerobic and aerobic respiration.
Energy flow and cycles of matter also occur in ecosystems through interactions between organisms and their physical environment, including food chains and webs and biogeochemical cycles.
Solar energy is converted into chemical energy through photosynthesis, with primary productivity measured as Gross Primary Productivity (GPP) and Net Primary Productivity (NPP).
Energy is conserved and transformed from one form to another, but cannot be created or destroyed, according to the Law of the Conservation of Energy.

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Description

Learn about the flow of energy and cycles of matter in ecosystems, including anaerobic and aerobic respiration, cellular respiration, and biogeochemical cycles. Understand how energy flow and cycles of matter occur within organisms and in the interactions between organisms and their physical environment.