Seeing all of the funiculi connecting all the zooids, and knowing that the 3 types of zooids cannot live independently, why don't we consider the colony to be one single animal? Thank you for this wonderful video!
You're basically asking "what is the difference between an individual and a colony", which is a difficult question! One way of defining colony is “a group of genetically identical, multicellular units that are physiologically connected to each other but can survive and function independently.” In bryozoans that is always (to my knowledge) true of one kind of zooid, the autozooid (the one that feeds and reproduces sexually). That is, if you had a colony of 1000 autozooids and carefully dissected one out, it should be fine. You’re right that there are other kinds of zooids that cannot live independently, because they can’t feed on their own. But autozooids should always be able to live on their own, and to produce new dependent zooids (e.g., aviculariae) if the species has the ability to make those. That definition works for most things that most biologists consider colonies (e.g., stony corals, bryozoans, compound ascidians), but I can think of a few possible exceptions, too. Those would be very highly integrated colonies that have a determinate colony form, like, for example, sea pansies (see the anthozoan video!). I imagine that if you dissected out an autozooid of a sea pansy it would not survive too long. They just seem TOO integrated. But maybe I’m wrong, I don’t know if that’s been done. It's worth trying to think up a definition of “individual” to contrast with how I just defined “colony” (which is not how all biologists would define it, for sure)!
Thank you for this up close look at these fascinating invertebrates. They are fascinating under your microscope however, I'm not sure I want them colonizing all over my aquarium. What eats them? I've seen pond snails on an otherwise healthy Sagittaria subulata but they don't appear to be eating the colony.
Thank you for this lecture and for allowing to use the image content. I will teach invertebrate zoology in Brazil this semester and I will use it for sure !!
I've been getting super into cnidarians! This was awesome to see. Love microbiology, love cnidarians, love this video! Definitely going to check out your channel Edit: I watched a video that said bryozoans were cnidarians, but I did more research and see that isn't true. Which is cool, because now I have a whole new phylum to learn about!!
The content of your videos is interesting, especially the up close live footage, which is useful in understanding these unique organisms, but your vocal fry is very distracting.
Never seen a stalked ciliate before! I'm always hoping for entoprocts. We used to look for them on the back of the polychaete Aphrodita or on the edge of Diopatra tubes. Now I'm wondering if what used to find were actually ciliates.
@@nickschooler5626 Here's something very similar on another bryozoan: www.microscopy-uk.org.uk/mag/indexmag.html?www.microscopy-uk.org.uk/mag/artmar01/protoz2.html
