some writing to go with the picture below , online HERE
the story of the tunicates
and how they became our ancestors - from an online slideshow HERE about the evolution of fish , by Christina Wood ... via evolving into first hagfish and lampreys which are their nearest relatives , then bony fishes , lung fish and then land vertebrates
but it is a long slideshow , so below are some of the slides of the tunicate bits ,
the tunicate ( also called a " sea squirt " )
I'm sitting , glowing , sifting plankton on a rock -
and I would say the world is good
as far as I can tell - it seems okay
to see me now you wouldnt think that I was not a plant
I ate my brain - I didnt need it once I'd found my home
I once had senses and a spinal cord
but they were just annoying once I settled
I ate them when I ate my swimming tail
that brought me here along the currents
swimming like a tadpole - searching for a place to anchor
I like it here - this rock - and this is just as well
I'm glued to it and will not let it go
I'm bioluminescent - don't you know -
I just live here . I sift and I pulsate and glow
A.G 23/05/2019
so - it happened by Neoteny - which is to say by cutting out the adult stage and we are descended from the larvae of tunicates - aka Sea Squirts
.... who knew ?
well - not ME - until yesterday !
I will just explain how I came across these -
it wasn't that I was reading Biology text books for fun - it was just Clickbait ! - how could I resist " 10-weirdest-bizarre-animals-found "
and the Tunicates that eat themselves are listed as no 10
10. Tunicate
This one is not so exciting to look at, but it totally wins the bizarre animal contest. It is colloquially known as a “sea squirt.” This is a sea critter that eats its own brain. A marine invertebrate, it spends part of its life in a larval stage where it can swim around in the water much like a fish or any other mobile animal.
This is a relatively brief period in the sea squirt’s life. They cannot feed in this stage, so they swim off, find a nice little bit of seabed to settle in on, and then plant themselves.
Once there, they start feeding. They also begin absorbing their mobility features and gills. The eyes and notochord (like a spine) go next. Finally, the brain is absorbed. Having no need to move about anymore, all of these body parts are considered superfluous by nature and dispensed with (an intriguing indicator that eyes and brains are necessarily mainly for reasons of mobility and are unnecessary for stationary organisms like plants—no wonder many of us feel an urge to travel).
The material is then recycled to create whole new body systems, including digestive, reproductive, and circulatory systems. Then the hermaphroditic tunicate reproduces, expelling brand new sea squirts into the world. It doesn’t get much more alien than that.
https://www.conservationinstitute.org/10-weirdest-bizarre-animals-found/
