noun, plural: autotrophs
Autotrophs are the producers in a food chain, such as plants on land or algae in water. They are also referred to as the producers of the food chain. They are capable of manufacturing their own food by photosynthesis or by chemosynthesis. Thus, autotrophs may be photoautotrophs or chemoautotrophs.
Photoautotrophs are autotrophs that produce complex organic compounds such as carbohydrates, fats, and proteins with the absorption of light. This process mediated by light is called photosynthesis. Photosynthesis is a process wherein plants absorb light from a light source (e.g. sunlight) and use carbon dioxide, inorganic salts, and water to produce an energy-rich carbohydrate like glucose (C6H12O6) and to produce oxygen (O2) as a by-product. Photoautotrophs are land plants and photosynthetic algae. These organisms have light-capturing pigments such as chlorophyll.
Chemoautotrophs are those that make their own food by chemosynthesis. Chemosynthesis is a process by which some organisms, such as certain bacteria, use chemical energy to produce carbohydrates. They utilize inorganic compounds such as hydrogen sulfide, sulfur, ammonium, and ferrous iron as reducing agents.
Word origin: Greek autos (self) + trophe (nutrition)
- atotrophic (adjective)