The Evolution of Photosynthesis

Photosynthesis Overview

• The oldest and most common form of photosynthesis is oxygenic photosynthesis.

Adaptations for Arid Conditions

• The Crassulacean acid metabolism (CAM) pathway is an adaptation for photosynthesis in arid conditions.

Early Photosynthesis

• The first photosynthetic organisms likely used ferredoxin as the reducing agent.
• Geobiological studies indicate that life existed at least 3.5 billion years ago.

History of Photosynthesis Discovery

• Joseph Priestley first published about the process of photosynthesis in 1779.

Photosynthesis Mechanism

• The primary source of hydrogen and electrons used in photosynthesis is water.

CO2 Incorporation

• The C4 pathway incorporates CO2 into four-carbon compounds before the Calvin cycle.

CAM Plants

• The primary adaptation of CAM plants for photosynthesis is the ability to open their stomata at night and store CO2, reducing water loss.

Fossil Record

• Fossils of filamentous photosynthetic organisms have been dated to around 1.2 billion years ago, based on recent studies of photosynthesis.

Discovery of Photosynthesis

• Joseph Priestley discovered the process of photosynthesis and first published about it in 1779.