EVERYDAY SCIENCE

Detailed explanation-1: -Tree adapted from Pace (1997). Overwhelming evidence indicates that eukaryotic photosynthesis originated from endosymbiosis of cyanobacterial-like organisms, which ultimately became chloroplasts (Margulis, 1992).

Detailed explanation-2: -Chloroplasts of plants and algae are currently believed to originate from a cyanobacterial endosymbiont, mainly based on the shared proteins involved in the oxygenic photosynthesis and gene expression system.

Detailed explanation-3: -Cyanobacteria (also called blue-green algae) are an ancient group of photosynthetic microbes that occur in most inland waters and that can have major effects on the water quality and functioning of aquatic ecosystems. They include about 2000 species in 150 genera, with a wide range of shapes and sizes.

Detailed explanation-4: -Cyanobacteria are aquatic and photosynthetic, that is, they live in the water, and can manufacture their own food. Because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see.