Nutrition Modes in Organisms

Overview

The class introduces nutrition in plants and animals, defining nutrition and its two main modes: autotrophic and heterotrophic. It outlines subtypes of autotrophic nutrition and previews heterotrophic types to be covered next.

Definitions of Nutrition and Nutrients

• Nutrition: mode by which organisms acquire and utilize nutrients from the environment.
• Nutrient: anything taken in as food; any substance ingested as food counts as a nutrient.

Modes of Nutrition

• Two main modes: autotrophic and heterotrophic.
• Autotrophic organisms manufacture complex food from simple substances.
• Heterotrophic organisms obtain complex food from other organisms.

Autotrophic Nutrition

• Simple substances used: carbon dioxide, water, mineral chemicals (e.g., nitrates).
• Organisms make their own complex food internally.

Subtypes of Autotrophic Nutrition

• Photosynthesis: green plants make food using light; “photo” means light, “synthesis” means to make.
• Chemosynthesis: organisms make food using chemical substances from the environment.

Photosynthesis Essentials

• Meaning: light-driven making of food by green plants.
• Key idea: do not forget the reactants required for photosynthesis.
• Typical simple inputs: carbon dioxide and water; sunlight provides energy.

Heterotrophic Nutrition

• Definition: organisms take in complex food materials (proteins, carbohydrates, fats) from other organisms.
• Requirement: organisms must find and ingest other organisms to obtain nutrients.
• Organisms using this mode are called heterotrophs.

Preview of Heterotrophic Types

• To be covered next: saprophytism, symbiosis, mutualism, parasitism.

Key Terms & Definitions

• Autotrophs: organisms that manufacture their own food from simple substances.
• Heterotrophs: organisms that obtain complex food from other organisms.
• Photosynthesis: process where green plants make food using light.
• Chemosynthesis: process where organisms make food using chemical substances from the environment.

Summary Table: Modes and Subtypes

Action Items / Next Steps

• Review reactants and concepts of photosynthesis.
• Prepare to study heterotrophic types: saprophytism, symbiosis, mutualism, parasitism.