5.2.2 Energy Flow

• What does energy flow refer to in ecosystems?

  Energy transfer through trophic levels
• Energy enters the ecosystem through photosynthesis
• Energy flows from producers to primary consumers to secondary consumers.
• What are the two primary energy sources in ecosystems?

  Sunlight and chemical compounds
• Sunlight is used by producers for photosynthesis
• Chemoautotrophs use sunlight to generate energy.

  False
• What do trophic levels represent in an ecosystem?

  Feeding positions in the ecosystem
• Only about 10% of the energy is transferred at each trophic level.
• Order the trophic levels from highest to lowest energy transfer efficiency:

  1️⃣ Producers

  2️⃣ Primary Consumers

  3️⃣ Secondary Consumers

  4️⃣ Tertiary Consumers
• If plants capture 1000 units of energy, apex predators will obtain 10 units.

  False
• What type of organisms use chemical compounds as an energy source?

  Chemoautotrophs
• Energy loss at each trophic level occurs through respiration, waste, and heat.
• Energy transfer efficiency remains constant at all trophic levels.

  False
• What is the difference between a food chain and a food web?

  Linear vs. interconnected network
• What are primary consumers also known as?

  Herbivores
• Tertiary consumers are also known as apex predators
• Only about 10% of energy is transferred between trophic levels in ecosystems.
• What are the three main reasons for energy loss between trophic levels?

  Respiration, waste, heat
• A food chain has a single pathway
• Food webs are more stable than food chains.
• What is an example of a food chain?

  Plants → grasshoppers → frogs → snakes
• Ecological efficiency is calculated as the percentage of energy transferred
• What is the formula for ecological efficiency?

  $Ecological Efficiency =$$\frac{Energy transferred}{Energy available} \times 100$
• Digestibility of food is a key factor affecting ecological efficiency.
• What is the primary source of energy input in ecosystems?

  Photosynthesis
• Ecosystems rely on two primary energy sources: sunlight and chemical compounds
• Match the energy source with its description:

  Sunlight ↔️ Radiant energy used by producers

  Chemical Compounds ↔️ Energy from chemical reactions
• What is the role of chemoautotrophs in ecosystems?

  Derive energy from chemical reactions
• Sunlight is converted into chemical energy during photosynthesis.
• Trophic levels include producers, primary consumers, secondary consumers, and tertiary consumers
• Why is energy transfer between trophic levels only about 10% efficient?

  Energy loss through respiration
• A food chain is a linear sequence showing energy flow, while a food web is an interconnected network
• Match the feature with the correct structure of a food chain or food web:

  Structure ↔️ Linear for food chain, complex network for food web

  Number of pathways ↔️ Single for food chain, multiple for food web
• What is detritus in an ecosystem?

  Dead organic matter
• Decomposers play a primary role in recycling nutrients
• Decomposers break down detritus into simpler inorganic substances.
• Key factors affecting ecological efficiency include digestibility of food, energy loss due to respiration, and waste production
• Match the key factor with its description:

  Digestibility ↔️ How effectively organisms extract energy from food

  Energy Loss ↔️ Energy used for respiration and functions

  Waste Production ↔️ Energy excreted as waste
• Detritus is dead organic matter, while decomposers are organisms that break down detritus into simpler inorganic substances
• Decomposers recycle nutrients back into the ecosystem for producers to use.