The evolution of photosynthesis...again?

Area of Science:

• Astrobiology
• Evolutionary Biology
• Biochemistry

Background:

• Photosynthesis enables large planetary biomass and oxygenated atmospheres.
• Oxygenic photosynthesis facilitated the evolution of complex life on Earth.
• Six prerequisites for biological carbon fixation were present on early Earth.

Purpose of the Study:

• To explore the likelihood of photosynthesis evolving on other planets.
• To understand the fundamental requirements for carbon fixation in life's evolution.
• To assess the probability of carboxylase evolution.

Main Methods:

• Inventory and comparison of carbon-fixation enzymes.
• Analysis of early Earth conditions and planetary system chemistry.
• Evaluation of evolutionary pressures for carbon fixation pathways.

Main Results:

• Carbon fixation is a fundamental process in life, likely evolved multiple times.
• The evolution of photosynthesis is probable given the necessary prerequisites.
• While oxygenic photosynthesis may be rare, non-oxygenic forms are plausible elsewhere.

Conclusions:

• Photosynthesis is a likely evolutionary outcome for extraterrestrial carbon-based life.
• The study supports the search for life beyond Earth by highlighting probable biological processes.
• Understanding carbon fixation provides insights into life's fundamental requirements and potential diversity.