The environment is a dynamic system where physical (abiotic) and biological (biotic) components interact continuously, driving processes essential for life. These interactions often involve complex chemical reactions that sustain ecosystems, regulate biogeochemical cycles, and maintain ecological balance.
For the classification of these components, read Components of Environment: Biotic and Abiotic.
Contents / Index
Photosynthesis: conversion of solar energy to chemical energy
A key example is photosynthesis, in which green plants use sunlight, water, and carbon dioxide to produce glucose and oxygen, thereby providing the primary energy source for higher trophic levels.
Plants (biological) utilize sunlight (physical), carbon dioxide (CO2), and water (H2O) to synthesize glucose, releasing oxygen (O2) as a byproduct.
6CO2 + 6H2O → C6H12O6 + 6O2
Physical components
Sunlight provides energy for the reaction, CO2 is absorbed from the atmosphere, and water is sourced from the soil.
Biological components
Chlorophyll in the plant chloroplasts captures light energy, while enzymes catalyze the conversion of CO2 and H2O into glucose.
Nutrient cycling
Nutrient cycling further connects biotic and abiotic components, as saprotrophs break down organic matter into simpler substances—releasing essential elements like nitrogen, phosphorus, and carbon back into the environment—which plants then reabsorb for growth and reproduction.
(C6H10O5)n + nH2O → nC6H12O6
Glucose is further oxidized to CO2 and H2O.
Nature of interactions
Dependency
Biotic factors depend on abiotic factors for survival. For example, plants (biotic) require sunlight, water and minerals (abiotic) for photosynthesis. Conversely, biotic components can influence abiotic factors. For instance, dense forest vegetation can affect soil quality and moisture levels through processes like transpiration and decomposition.
Energy and minerals flow
The flow of energy through ecosystems begins with abiotic components. Plants first capture this energy during photosynthesis, converting it into chemical energy stored in organic matter. This energy then moves through the food web as animals consume plants and each other.
When organisms die or produce waste, nutrients are returned to the soil (abiotic), enriching it for future plant growth. These exchanges illustrate the movement of energy and nutrients between biotic and abiotic components.
Lichens and plant roots
For the related example of rock breakdown, soil formation and nutrient cycling, read Biological Weathering by Lichens and Plant Roots.
Question from the chapter
What are the Physical and Biological Components of environment? How do the physical and biological components of environment interact with each other? Explain with example.
[Arunachal PSC ACF (MAIN) 2018, Environmental Science Optional, 6 M] — attribution as supplied in the notes.
Quick revision
- Photosynthesis connects sunlight, atmospheric carbon dioxide and soil water with plants.
- Chlorophyll captures light energy, and enzymes support glucose formation.
- Saprotrophs return nutrients to the environment for plant growth and reproduction.
- Biotic components depend on abiotic factors and can also influence them.
- Energy passes through the food web; dead organisms and wastes return nutrients to the soil.