The correct option is 1 and 3 only.
Explanation
Ecosystem dynamics are driven by the flow of energy and the cycling of nutrients. The flow of energy is governed by the laws of thermodynamics, characterizing how energy enters the system and how it diminishes as it moves through various trophic levels.
Statement-wise Analysis:
- Statement 1 is Correct: Producers (autotrophs), such as green plants and phytoplankton, capture solar energy through the process of photosynthesis. They convert light energy into chemical energy (organic compounds), thereby making energy available to the rest of the ecosystem (consumers and decomposers).
- Statement 2 is Incorrect: Energy transfer across trophic levels is not 100% efficient. According to Lindeman’s 10% Law, only approximately 10% of the energy is transferred from one trophic level to the next higher level. The remaining energy is lost to the environment as heat due to respiration, metabolic activities, and movement.
- Statement 3 is Correct: Human activities act as a significant biotic factor influencing the environment. Anthropogenic actions such as deforestation, pollution, urbanization, and agriculture alter physical and chemical conditions, impacting ecosystem stability and biodiversity.
Key Takeaway: Energy flow in an ecosystem is unidirectional and decreases at each successive trophic level due to respiratory losses, adhering to the 10% Law of energy transfer.