SS1 SECOND TERM, WEEK 5, ENERGY TRANSFORMATION IN NATURE

 Energy Transformation in Nature

Energy transformation in nature refers to the conversion of energy from one form to another in biological and ecological systems. The primary source of energy for most life forms is the sun, which is transformed through various biological and physical processes.

Key Energy Transformations in Nature:

1. Photosynthesis – Plants, algae, and some bacteria capture solar energy and convert it into chemical energy in the form of glucose. $$6CO_2 + 6H_2O + Light Energy → C_6H_{12}O_6 + 6O_2$$
2. Cellular Respiration – Organisms break down glucose through aerobic or anaerobic respiration to release ATP (usable energy). $$C_6H_{12}O_6 + 6O_2 → 6CO_2 + 6H_2O + ATP$$
3. Decomposition – Dead organisms are broken down by decomposers (fungi, bacteria), converting chemical energy into heat and nutrients for the soil.
4. Trophic Interactions – Energy is transferred from producers to herbivores, carnivores, and decomposers through the food chain.

Energy Loss in Ecosystems

In ecosystems, energy is lost at each trophic level due to metabolic processes and inefficiencies in energy transfer.

How Energy Is Lost:

• Heat Loss: Due to respiration, organisms release heat energy to the environment.
• Metabolic Processes: Energy is used for movement, digestion, reproduction, and maintaining homeostasis.
• Undigested Material: Some energy is lost in feces and excretory products.
• Decomposition: Dead organisms contain unused energy, which decomposers break down, further releasing heat.

Energy Transfer Efficiency:

• Only about 10% of the energy is transferred from one trophic level to the next (known as the 10% rule).
• The rest (~90%) is lost as heat or used in metabolic activities.

Energy Flow Diagram:

☀️ Sunlight (100%) → 🌱 Producers (1-2%) → 🐛 Primary Consumers (10%) → 🦅 Secondary Consumers (1%) → 🐆 Tertiary Consumers (0.1%)

Implication: The higher the trophic level, the less energy is available, explaining why food chains are usually limited to 4-5 levels.

 Laws of Thermodynamics

First Law of Thermodynamics (Law of Energy Conservation)

• Energy cannot be created or destroyed; it can only be transformed from one form to another.
• Example in Ecology: Solar energy is converted into chemical energy by plants (photosynthesis).

Second Law of Thermodynamics (Law of Entropy Increase)

• Energy transfers are never 100% efficient; some energy is always lost as heat.
• This results in increasing disorder (entropy) in natural systems.
• Example in Ecology:
  • Heat is lost at each trophic level in a food chain.
  • A lion eating an antelope receives less energy than the antelope originally consumed from plants.

 Application of Thermodynamic Laws to Ecological Phenomena

1. Food Chains & Energy Flow

   • First Law: Energy is transferred from the sun to plants and then to consumers.
   • Second Law: At each level, some energy is lost as heat, making energy flow unidirectional and inefficient.

2. Ecosystem Productivity

   • First Law: The total energy entering an ecosystem (Gross Primary Productivity - GPP) is conserved.
   • Second Law: Only a fraction of this energy (Net Primary Productivity - NPP) is available for herbivores, as some is lost through respiration.

3. Decomposition & Nutrient Recycling

   • First Law: Organic matter decomposes, releasing nutrients back to the soil without creating or destroying energy.
   • Second Law: Decomposition releases heat, contributing to entropy.

4. Climate Change & Energy Balance

   • The Earth absorbs solar radiation, but due to inefficiencies (Second Law), some energy is lost as heat, contributing to global warming.

ASSIGNMENT

State and explain the First Law of Thermodynamics with a relevant ecological example.

How does the Second Law of Thermodynamics explain energy inefficiency in food chains?