Annelids Memes

Evolutionary flex tape couldn't fix this taxonomic rivalry. Annelids (worms) evolved closed circulatory systems where blood stays neatly contained in vessels, while arthropods (spiders, insects) said "nah" and went with open systems where blood just sloshes around their body cavities like a biological soup kitchen. 500 million years later and they're still refusing to upgrade their plumbing. Classic arthropod stubbornness.