Oddly, when you type this question into Google, you get lots and lots of links pointing you to bacteria that are smaller than other bacteria. Almost lost in the debris is a page from UCMP Berkeley titled “Bacteria: Fossil Record”, which states “Cyanobacteria are larger than most bacteria.” (It’s like they heard The Five-Year-Old’s question, isn’t it?)
Fossil cyanobacteria (more commonly known as blue-green algae) date back to the Precambrian period (some 3.5 billion years ago), but there are still cyanobacteria around today.
Amazingly, the modern versions aren’t that much different from the specimens preserved in the fossil record. As the researchers at Berkeley somewhat drily put it: the cyanobacteria show “the most extreme conservatism of morphology of any organisms.” In other words, these little guys can be thought of as “living fossils.”
- Cyanobacteria May Make Good Sunscreen (bellasugar.com)
- Sapphire Boosts Yields from Blue-Green Algae, Signs Earthrise Deal – Xconomy (xconomy.com)
- How the First Plant Came to Be (scientificamerican.com)