Specimen Prep - Ecosystem

Specimen Prep Guide: Ecosystem

Key Concepts (Recall & Understanding)

• Ecosystem Structure and Function: Understand the components of an ecosystem (producers, consumers, decomposers) and the processes of productivity, decomposition, energy flow, and nutrient cycling.
• Food Chains & Food Webs: Differentiate between food chains and food webs. Understand the concept of trophic levels.
• Ecological Pyramids: Know the different types of ecological pyramids (pyramid of numbers, pyramid of biomass, pyramid of energy).
• Nutrient Cycling: Understand the carbon cycle and the phosphorus cycle.
• Ecological Succession: Differentiate between primary and secondary succession.

Application Corner

• Problem Type: Constructing a food chain or food web for a given ecosystem. Drawing ecological pyramids.
• Example: In a forest ecosystem, a deer eats grass, and a tiger eats the deer. What are the trophic levels of the grass, deer, and tiger? (Answer: Grass - T1, Deer - T2, Tiger - T3).

Analytical Thinking

• Scenario: Why is the pyramid of energy always upright?
• Analysis: Because there is a progressive loss of energy at each successive trophic level (the 10% law). The energy at a lower trophic level is always greater than the energy at a higher trophic level.
• Diagram Interpretation: Be able to interpret diagrams of nutrient cycles.

Key Case Study

• The 10% Law of Energy Transfer: Proposed by Lindeman, this law states that during the transfer of energy from one trophic level to the next, only about 10% of the energy is stored as flesh. The rest is lost during transfer, respiration, or is not consumed.

Assertion-Reason Practice

1. Assertion: Decomposers play a crucial role in an ecosystem. Reason: They break down dead organic matter and release nutrients back into the soil.

   • (a) Both Assertion and Reason are true and Reason is the correct explanation for Assertion.

2. Assertion: The pyramid of biomass in a sea is generally inverted. Reason: The biomass of fishes far exceeds that of phytoplankton.

   • (a) Both Assertion and Reason are true and Reason is the correct explanation for Assertion.

HOTS (Higher-Order Thinking Skills) Question

• What is the significance of the decomposer food chain?
  • Answer: The decomposer food chain is essential for nutrient cycling. Without decomposers, the nutrients locked in dead organic matter would not be returned to the ecosystem, and the entire ecosystem would eventually collapse.