Would it be possible for a cilliate, such as Stentor, to evolve into a large multicellular organism similar in form to the original unicellular body-plan?


Volvox style?



The constituent organism of a volvox colony are not ciliates, but photosynthetic algae with flagellae. Their photosynthetic lifestyle lends itself to scaling up; more surface areas and predators the size of the individual component cells cannot fit the colony in its mouth.

Ciliates are non-photosynthetic which makes it trickier, but I can imagine a similar scaleup for those that feed with a sort of ram-scoop mouth. Volvox have just 2 cell types - the reproducers in the middle and the workers on the outside but a colonial ciliate with the same body plan would probably need both of those and a third type dedicated to enclosing food items in enormous 1-cell vacuoles.

  • $\begingroup$ But what about the cilliate splitting into multiple cells in the cilliate's original form? $\endgroup$ – Ichthys King May 12 '20 at 9:40
  • $\begingroup$ You want a facultative multicellular creature? Something like a slime mold where they can operate as individuals or a commune? $\endgroup$ – Willk May 12 '20 at 14:47
  • $\begingroup$ No, I mean were the cilliate goes from, for example, a unicellular cone-shaped creature directly to a multicellular cone-shaped creature $\endgroup$ – Ichthys King May 12 '20 at 20:41
  • $\begingroup$ There are colonial ciliates; hydrotheca for one. I think stentor have also been observed clustering. But as you say, you would need specialists in the colony before making the jump to true multicellularity. $\endgroup$ – rek Jul 17 '20 at 17:37

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