Echinoderms

>>9167569
Well first you need to understand how echinoderms come to have radial symmetry. Bilateral symmetry is conserved in larvae of echinodermta, and develops into a radial-symmetrical form during metamorphosis. like this https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2176165/
Now for the interesting part, eco-evolutionary dynamics. it will help if you have a basic understanding of the material reviewed here https://sci-hub.cc/http://www.nature.com/nrg/journal/v16/n10/full/nrg3982.html
A few hypothesis start to come to my mind. If we take this hypothesis for the common ancestry of echinoderms to be true as i found it on Wikipedia
>It is hypothesised that the ancestor of all echinoderms was a simple, motile, bilaterally symmetrical animal with a mouth, gut and anus. This ancestral stock adopted an attached mode of life and suspension feeding, and developed radial symmetry as this was more advantageous for such an existence. The larvae of all echinoderms are even now bilaterally symmetrical and all develop radial symmetry at metamorphosis. The starfish and crinoids still attach themselves to the seabed while changing to their adult form
and use it, or atleast something like it as an axiom for forming new hypothesizes.

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>>9167779
There are a few insights that this gives
1, that the mutation causing radial symmetry was selected for its evolutionary utility to a specific pattern of ecological and/or biological behavior (neolamarckian selection)
possible examples include but are not limited to any one or more of the following; Movement ((mobility in a bethnic environment better allowing for; increased ability to find food(finding the right physiological oceanographic conditions for filter feeding), escaping predators, finding mates and mating, and thus survival to reproduction and recruitment.), Maturation (knowing that bilateral symmetry was preserved up until metamorphosis when the larvae attaches itself to the sediment to form into adult it follows that any mutation that benefited this behavior would be selected for, if in some way radial symmetry bettered allowed for the recruitment of larvae into juveniles, or juveniles to sexually mature adults, i would need to do some more research to start on this one. some other things that come to mind are the ability to fully rejuvenate tissue, better digestion or physical ability to eat, perhaps something to do with neurons.
there is alot of possible explanations and i dont even have the time to discuss what i have already brought up.
im going to leave now. in the mean time i would be happy if someone would bring up mores questions pertaining to this or ecology evolution and marine biology in general
talking about this for cnidarians or the evolution of decapod crustaceans into crab like forms

>>9167569
>Does anyone here have any theories on why echinoderms evolved pentaradial symmetry?

Why not?

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>>9167569
Speak english mr science man
>you guys know why starfish are shaped like stars? nothing else is shaped like stars

>>9167779
>It's more useful for an attached filter feeder
That's probably a good explanation.

>>9168455
WE
WUZ
ASTEROIDS N SHEIT

>>9167569
Meiotic mutations occur by independent assortment. These mutations by chance may be favorable for their environment and produce more offspring with those traits. Think back to how to zygotes develop into embryos. The way those embryos form is somewhat dependent on outside factors can be environmental pressures (Temperature, chemicals, etc) that change the normal way they would develop. So, in the case of Asterozoa, they probably just had those traits selected for. (I think)

I just had an exam on this stuff today. ;/

does anyone know what those little walky tentacley things under an enchinoderm are called?? sorry im new to marine bio and none of my girlfriends can help out and i tend to shy away from guys... 4chan is like my help center

>>9169304
tube feet?