Biology Notes Study Guide PDF

Topic 1.1: How Energy Enters the Biosphere Energy in Organisms All living things need energy to grow, move, and survive. Energy is released in the body through cellular respiration (breakdown of carbohydrates) or fermentation (without oxygen). Producers (like plants) use photosynthesis to captur...

Topic 1.1: How Energy Enters the Biosphere Energy in Organisms All living things need energy to grow, move, and survive. Energy is released in the body through cellular respiration (breakdown of carbohydrates) or fermentation (without oxygen). Producers (like plants) use photosynthesis to capture energy from sunlight and make food (carbohydrates). Consumers (like animals) eat other organisms to get their energy. Photosynthesis & Cellular Respiration Photosynthesis: Plants use sunlight, water, and carbon dioxide to make food (glucose) and oxygen. Equation: 6CO2 + 6H2O + light energy → C6H12O6 + 6O2 Cellular Respiration: Organisms break down food (like glucose) with oxygen to release energy. Equation: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy Producers and Consumers Producers (autotrophs) make their food using sunlight. Consumers (heterotrophs) get energy by eating producers or other consumers. Primary Consumers: Herbivores that eat producers, first in the food chain. Examples: insects, deer. Secondary Consumers: Carnivores that eat primary consumers and producers, second in the food chain. Examples: frogs, and small birds. Tertiary Consumers: Apex predators that eat secondary consumers, third in the food chain. Examples: hawks, lions. Energy Transfer Most energy from the sun is either reflected or absorbed by the atmosphere. Only 1-2% of the sun’s energy is captured by producers to make food. Albedo is the measure of how much sunlight is reflected by a surface. Lighter surfaces have a higher albedo and reflect more sunlight. An example of surfaces with high albedo are snow and ice caps, while low albedo are oceans or forests. Chemosynthesis Some organisms, like bacteria near deep-sea vents, use chemosynthesis to get energy from chemicals (like hydrogen sulphide), not sunlight. The process by which food is made by bacteria or other living things using chemicals as the energy source, typically in the absence of sunlight. First and Second Law of Thermodynamics FIRST LAW: Energy cannot be created or destroyed, only transformed from one to another. SECOND LAW: Energy is never 100% efficient and becomes less useful over time, mostly from loss of heat.