Rucete ✏ Campbell Biology In a Nutshell
Unit 2 THE CELL — Concept 10.1 Photosynthesis Feeds the Biosphere
Photosynthesis is the process by which light energy is transformed into chemical energy, supporting nearly all life on Earth either directly or indirectly.
Autotrophs: The Producers
- Autotrophs make their own organic molecules from CO₂ and inorganic materials
- They do not rely on other living organisms for food
- Photoautotrophs use sunlight as an energy source—includes plants, algae, and some prokaryotes
- Autotrophs are the base of the food chain and sustain all non-autotrophs
Heterotrophs: The Consumers
- Heterotrophs obtain organic material by consuming other organisms or organic matter
- They include animals, fungi, and many prokaryotes
- Decomposers, like fungi and bacteria, feed on dead material and waste
- All heterotrophs ultimately depend on autotrophs for energy and oxygen
Fossil Fuels and Photosynthesis
- Fossil fuels formed from ancient autotrophs store sunlight energy from the past
- Biofuel strategies (e.g., using photosynthetic algae) aim to recycle current sunlight energy
- Using algae near CO₂-rich environments (like factories) enhances photosynthetic output and sustainability
In a Nutshell
Photosynthesis sustains life by converting sunlight into chemical energy. Autotrophs feed themselves and support all heterotrophs, including humans, making them essential to Earth's biosphere.