In the first Hitchhiker's Guide to the Galaxy, upon firing the Infinite Improbability Drive while trying to escape two missiles (with nuclear warheads attached), the missiles turned into a very surprised sperm whale and a bowl of petunias.
He goes on to describe "what went through the head of the whale", with a long dialog about coming to terms with its life (while shortly having to come to terms with no longer having one).
"Curiously enough, the only thing that went through the mind of the bowl of petunias as it fell was 'Oh no, not again'. Many people have speculated that if we knew exactly why the bowl of petunias had thought that we would know a lot more about the nature of the Universe than we do now."
Silliness aside, it's fascinating seeing unexpected discoveries like this -- and something like this really does underscore how large the body of knowledge is that "we don't know" about biology, in general.
Douglas Adams had a way of thinking which made him right about quite a lot of future discoveries/technologies, even though most of his predictions were meant as hyperbole...
She trained Pea Plants to associate airflow with light, causing them to grow towards a breeze expecting it to soon be followed with light.
That shows far more than just desensitization memory.
https://theconversation.com/pavlovs-plants-new-study-shows-p...
Some examples:
Bacteria can pass on memory to descendants, researchers discover https://phys.org/news/2018-04-bacteria-memory-descendants.ht...
Collective memory discovered in bacteria https://www.sciencedaily.com/releases/2016/03/160307153047.h...
Bacteria become “genomic tape recorders” https://news.mit.edu/2014/bacteria-storage-device-memory-111...
And slime mold (TED talk) https://www.youtube.com/watch?v=2UxGrde1NDA
First, the fact that bacteria can have memory!!
Second, the fact that this surprises me. Trivially, even for a single cell animal, it is not shocking that it might gain some survival advantage from having a memory of sorts, and that is really not a high bar to jump over in terms of required infrastructure. Almost any sort of very simple memory could be used advantageously.
It's an interesting thought experiment for me though to imagine.
Another interesting one is the box jellyfish with eyes yet appear to not have any brains for processing the images : https://www.livescience.com/13929-box-jellyfish-eyes-navigat...
Interestingly, that's what many people thought about animals too; Descartes famously described animals (all animals, including usual pets like dogs, etc.) as machines, mindless robots.
It's already common knowledge that plants communicate with one another about danger; why shouldn't they remember? Just because we don't know how doesn't mean it doesn't happen.