10% Rule & Food Webs (1.10 & 1.11)

Match

Match the following

• The First Law of thermodynamics

• The Second Law of thermodynamics

• Newton's First Law of Motion

Energy cannot be created or destroyed, only transformed.

The total entropy of an isolated system can never decrease over time.

An object at rest stays at rest and an object in motion stays in motion unless acted upon by a net external force.

• Energy cannot be created or destroyed, only transformed.

• The total entropy of an isolated system can never decrease over time.

• An object at rest stays at rest and an object in motion stays in motion unless acted upon by a net external force.

Multiple Choice

What happens to the majority of energy as it moves up each trophic level in a food web?

• It is lost as heat, metabolic processes, and waste

• It is stored in the next trophic level

• It is converted entirely to new biomass

• It disappears completely

Open Ended

How does the loss of energy at each trophic level affect the structure and stability of ecosystems?

Multiple Choice

Why is the 10% Rule important in understanding how energy moves through food webs?

• Because it explains why energy is lost at each trophic level and limits the number of trophic levels in an ecosystem.

• Because it shows how all energy is conserved and passed on to the next level.

• Because it describes how energy is created at each trophic level.

• Because it allows all organisms to receive equal amounts of energy.

Multiple Choice

In a tundra ecosystem, producers capture 21,000 kcal/m²/year of energy from the sun. About how much energy is available to tertiary consumers?

• 19 kcal/m²/year

• 210 kcal/m²/year

• 47 kcal/m²/year

• 2,150 kcal/m²/year

• 2.1 kcal/m²/year

Multiple Choice

In an aquatic food chain:
Phytoplankton → Zooplankton → Small Fish → Large Fish
Large fish receive 8 kcal/m²/year of energy. Assuming about 10% efficiency at each trophic level, what was the net primary productivity (NPP) of the phytoplankton?

• 8,200 kcal/m²/year

• 790 kcal/m²/year

• 7,650 kcal/m²/year

• 80 kcal/m²/year

• 800 kcal/m²/year

Multiple Choice

If primary consumers have 1,500 kcal/m²/year & secondary consumers have 140 kcal/m²/year, what is the energy transfer efficiency from primary to secondary consumers? (hint: it is usually about 10% efficient)

• 9.3 %

• 10.7 %

• 10.1 %

• 9.7 %

• 10.4 %

Open Ended

Predict what would could possibly happen to biotic and abiotic systems if lions were removed from the savanna (tropical grassland ecosystem)?

Multiple Choice

Which of the following is an example of a secondary consumer?

• Grasshopper

• Frog

• Oak tree

• Bacteria

Draw

Draw a food web that has 10 trophic levels