Energy is required for life.

Energy is required for life:

Energy is required to transfer matter between the environment and organisms.

• Sunlight (photosynthesis)
• Geothermal (chemosynthesis - much less common)
• The Earth is an open system for ____ but a closed system for ____.

Energy is required for life:

Energy is required to transfer matter between the environment and organisms.

• Sunlight (photosynthesis)
• Geothermal (chemosynthesis - much less common)
• The Earth is an open system for energy (heat is “lost”) but a closed system for matter (matter is conserved and recycled)

Topic 1.9 Trophic Levels:

LO: Explain how energy flows and matter cycles through trophic levels.

Energy is always conserved, but it changes in quality:

1st Law of Thermodynamics?

• ​

Energy is always conserved, but it changes in quality:

1st Law of Thermodynamics: Energy cannot be created or destroyed, energy is transferred from one form to another.

​

Energy is always conserved, but it changes in quality:

1st Law of Thermodynamics: Energy cannot be created or destroyed, energy is transferred from one form to another.

2nd Law of Thermodynamics?

Energy is always conserved, but it changes in quality:

1st Law of Thermodynamics: Energy cannot be created or destroyed, energy is transferred from one form to another.

2nd Law of Thermodynamics:

• Every energy transfer makes the universe more disordered

​

Energy is always conserved, but it changes in quality:

1st Law of Thermodynamics: Energy cannot be created or destroyed, energy is transferred from one form to another.

2nd Law of Thermodynamics:

• Every energy transfer makes the universe more disordered
• Entropy is a measure of this disorder

​

Energy is always conserved, but it changes in quality:

1st Law of Thermodynamics: Energy cannot be created or destroyed, energy is transferred from one form to another.

2nd Law of Thermodynamics:

• Every energy transfer makes the universe more disordered
• Entropy is a measure of this disorder
• With every energy transfer heat is lost

​

Energy is always conserved, but it changes in quality:

1st Law of Thermodynamics: Energy cannot be created or destroyed, energy is transferred from one form to another.

2nd Law of Thermodynamics:

• Every energy transfer makes the universe more disordered
• Entropy is a measure of this disorder
• With every energy transfer heat is lost
• Amount of useful energy is decreased with each transfer

Biogeochemical Cycles:

N, P, C, H₂O, S: Essential for life and each cycle demonstrates the conservation of matter on Earth.

Energy flow:

Energy flows from the sun to the lowest trophic levels and then upward to higher trophic levels.

Earth is an open system for energy but a closed system for matter!

Thank you Fungi!

Fungi and decomposers are an extremely important part of recycling matter on Earth but they are often overlooked!

Topic 1.10: Energy flow and the 10% rule

LO: Determine how the energy decreases as it flows through systems.

The 10% Rule:

• Chemical energy must be transferred from one organism to the next. At each trophic step 90% of energy is lost to maintaining the organism and as heat.
• At each transfer of energy, only 10% of energy is passed on to the next trophic level.

​

• Troph = Greek word for food or feeding
• Trophic level refers to a feeding level in the food chain

Topic 1.11 Food Chains and Food Webs

LO: Describe food chains and food webs, and their constituent members by trophic level.

Food webs are interlocking models of food chains. Arrows show us the direction of energy and matter flow.

Feedback Loops in Food Webs:

When species are removed or added, it can impact the entire food web.

Ex:

- Sea otters in kelp forests

- Wolves of yellowstone

- Puget Sound Orcas

Feedback Loops:

Systems involve feedback loops. A feedback loop is when a system output serves as an input for the same system.

​

Positive vs. Negative Feedback Loops:

Positive feedback causes the system to move further in the same direction. The output leads to the same inputs. Ex: warming→ ice melting → darker ocean leads to more warming and less reflection

Negative feedback causes the system to move in the opposite direction from the input. Negative feedback enhances stability.