In an ecosystem why is the number of trophic levels of a food chain usually limited?

The number of trophic levels in a food chain is primarily limited by the progressive loss of energy at each successive level. According to the second law of thermodynamics, energy transfer is inefficient, with a significant portion (approximately 90%) lost as unusable heat during respiration, maintenance, and metabolic processes [1][2][5]. This phenomenon, often referred to as Lindeman's ten percent law, dictates that only about 10% of the energy from one trophic level is converted into biomass available for the next level [5][6]. Consequently, the energy available diminishes so rapidly that after four or five levels, the remaining energy is insufficient to support a viable population of higher-level predators [1][5]. This creates an upward-tapering energy pyramid where the base of producers holds the maximum energy, and the top carnivores hold the least [2][3].

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > z.r.r. Trophic level interaction > p. 11
2. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > 2.4.3. Pyramid of Energy > p. 15
3. [5] http://www.hooghlywomenscollege.ac.in/ol%20doc/Energy%20flow%20through%20Ecosystem.pdf
4. [6] https://en.wikipedia.org/wiki/Ecological_efficiency
5. [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > 2.4. ECOLOGICAL PYRAMIDS > p. 13