D4.2 穩定與變化（生態系）：练习题

• a.

  Natural selection must be halted to prevent the extinction of less-adapted species.

• b.

  Nutrients must be recycled within the ecosystem, and there must be a continuous supply of energy.

• c.

  The population of apex predators must exceed the population of primary consumers.

• d.

  There must be a constant supply of organic matter from external ecosystems.

• a.

  Purchasing locally sourced goods and produce whenever possible.

• b.

  Consuming a largely plant-based diet from sustainable sources.

• c.

  Frequently engaging in international air travel for leisure.

• d.

  Actively recycling household waste materials.

• a.

  Competitive exclusion between herbivorous zooplankton and apex predatory fish.

• b.

  Biomagnification of persistent organic toxins causing exponential mortality at higher trophic levels.

• c.

  A top-down trophic cascade altering community structure across multiple lower trophic levels.

• d.

  A bottom-up control mechanism driven solely by increased abiotic nutrient loading.

• a.

  A critical threshold where a minor change in conditions causes a rapid and often irreversible shift to a new ecosystem state.

• b.

  The maximum rate at which a renewable resource can be harvested without reducing its future availability.

• c.

  The point during ecological succession at which gross primary productivity precisely equals total community respiration.

• d.

  A negative feedback loop that restores an ecosystem to its original baseline equilibrium following a major disturbance.

• a.

  Negative feedback stabilizing the forest community around its original carrying capacity.

• b.

  Primary succession establishing an equilibrium climax community from barren exposed rock.

• c.

  A regime shift across a tipping point leading to an alternate stable state maintained by feedback mechanisms.

• d.

  Directional natural selection that restores the original canopy density via rapid speciation.

先自己写一遍答案，再对照解题步骤。

先自己写一遍答案，再对照解题步骤。