This is fascinating stuff – evolution at work. Sounds like some of the theories about how eukaryotes first emerged. Check it out:
It looks like any other sea slug, aside from its bright green hue.
But the Elysia chlorotica is far from ordinary: it is both a plant and
an animal, according to biologists who have been studying the species for two decades.Not only does E. chlorotica turn sunlight into energy —
something only plants can do — it also appears to have swiped this
ability from the algae it consumes.Native to the salt marshes of New England and Canada, these sea
slugs use contraband chlorophyll-producing genes and cell parts called
chloroplasts from algae to carry out photosynthesis, says Sidney Pierce,
a biologist at the University of South Florida in Tampa.That genetic material has since been passed down to the next generation, eliminating the need to consume algae for energy.
