Energy in Organisms and Their Processes

Energy in Organisms

• All living things need energy for growth, movement, and survival
• Energy is released through cellular respiration (breaking down carbohydrates) or fermentation (without oxygen)
• Producers (plants) use photosynthesis to capture sunlight energy and create food (carbohydrates)
• Consumers (animals) obtain energy by consuming other organisms.

Photosynthesis and Cellular Respiration

• Photosynthesis: Plants capture sunlight, water, and carbon dioxide to produce glucose (food) and oxygen
• Equation: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂
• Cellular Respiration: Organisms break down food (like glucose) with oxygen, releasing energy
• Equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy

Producers and Consumers

• Producers (autotrophs): Make their own food using sunlight
• Consumers (heterotrophs): Obtain energy by eating producers or other consumers.
• Primary Consumers: Herbivores that eat producers (e.g., insects, deer).
• Secondary Consumers: Carnivores that eat primary consumers and/or producers (e.g., frogs, small birds).
• Tertiary Consumers: Apex predators that eat secondary consumers (e.g., hawks, lions).

Energy Transfer

• Most of the sun's energy is reflected or absorbed by the atmosphere
• Only 1-2% of the sun's energy is captured by producers to make food.

Albedo

• Albedo is a measure of how much sunlight is reflected by a surface
• Surfaces with high albedo (e.g., snow, ice) reflect more sunlight, while those with low albedo (e.g., oceans, forests) reflect less

Chemosynthesis

• Some organisms (e.g., bacteria near deep-sea vents) use chemosynthesis to obtain energy from chemicals instead of sunlight
• Chemosynthesis is similar to photosynthesis, but uses chemicals as the energy source.

First and Second Law of Thermodynamics

• First Law: Energy cannot be created or destroyed, only transformed
• Second Law: Energy transformations are never 100% efficient, some energy is lost as heat (making the process less useful over time)