What are photoautotrophs, plants, and algae?

Photoautotrophs are organisms that use sunlight and inorganic compounds to create organic materials through photosynthesis, sustaining their own metabolism. This diverse group includes plants, algae, and cyanobacteria, which form the base of many aquatic and terrestrial ecosystems. Eukaryotic photoautotrophs use chlorophyll within chloroplasts, while prokaryotes rely on free-floating thylakoids.

What we know

• Photoautotrophs utilize light energy from sunlight and elements from inorganic compounds to produce organic materials needed for their metabolism. [2]
• Plants, algae, and cyanobacteria perform oxygenic photosynthesis, which produces oxygen as a byproduct by splitting water molecules. [2, 3, 4]
• Most algae are photoautotrophs and serve as the main primary producers in aquatic ecosystems. [3]
• Eukaryotic photoautotrophs absorb photonic energy through chlorophyll in chloroplasts, whereas prokaryotic photoautotrophs use chlorophylls and bacteriochlorophylls in cytoplasmic thylakoids. [2]

Still open

• While most algae are photoautotrophs, some species are mixotrophs, heterotrophs, or parasites that rely partly or entirely on external energy sources.

Where to go next

• what caused itHow did cyanobacteria change early Earth?
• what followedHow does marine primary production sustain ocean life?
• how it workedHow does oxygenic photosynthesis work in chloroplasts?
• how we knowWhat fossil evidence exists for ancient algae?
• the bigger pictureWhat is primary production?
• an unexpected connectionHow are modern land plants related to ancient marine phytoplankton?Phytoplankton in the Silurian period evolved into red, brown, and green algae that eventually invaded land to become modern plants.

Sources

• [1]photoautotroph (Wikidata Q1960084) · CC0 1.0
• [2]Photoautotroph · CC BY-SA 4.0
• [3]Algae · CC BY-SA 4.0
• [4]Cyanobacteria · CC BY-SA 4.0
• [5]Marine primary production · CC BY-SA 4.0