Bacteria choose to swarm based on what happened to their great-grandparents
Even organisms without brains can remember their past: Scientists found that Escherichia coli bacteria form their own kind of memories of exposure to nutrients. They pass these memories down to future generations, which can help them evade antibiotics, the research team reported in the Proceedings of the National Academy of Sciences USA.
“We typically think of microbes as single-celled organisms [that each] do their own thing,” says Dartmouth College microbiologist George O’Toole, who studies bacterial structures called biofilms. In reality, bacteria frequently survive by working together. Much like honeybees relocating their hive, colonies of bacteria in search of permanent homes will often travel as collective units called swarms.
That’s why I specified both material and functional continuity: a plant cutting has the first, but not the second.
That matters here because without functional continuity, any epigenetic, memory-like functionality would have to be diffused throughout the organism’s entire substance if the cutting is going to retain it—while a bacterium undergoing cell division has an opportunity to copy any local memory-retaining features when it divides.