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[Supermikhail]

I'll be brief. I'm a short way into Porifera. Got inspired. Making sense of Burger.

Based on my earlier design of two-species polygonal colony. So, this is basically a floating sponge, which moves using flagella on the inside which move, I guess, in a spiral, creating a current and pushing the body forward. I decided that to grow in size and keep stable, it had to have some kind of frame, which is provided by the shelled cells. Soft cells on the picture are transparent, the frame is not, and the openings on the sides are to steer.

In afterthought, I guess using the same cells for movement and feeding isn't very efficient. Hm.

[Shoku]

That would depend on the buoyancy. If it can float without pushing any water around it doesn't need to move very well at all.

Stationary or moving it will push pretty much the same volume of water around. It could have both sides direct current inward and let it leave through the steering hole (or the other way around,) when it was in food abundant areas. Because the currents spiral through it I suspect this would make it spin rather than push it in a straight line.

On the less positive end of things sponges would have a hard time moving water through one large opening and out another. They usually pull water in through a large number of openings that just converge to flow up through the big opening. There should still be some size range where this would work but I can't quite decide how large. The other problem is growing into that frame. Juveniles should probably have a narrower opening and outer diameter and thus they would have to leave the old frame behind or deconstruct it at some point. Do they molt and slide off of it at some point?
An alternative would be to split the round portions and have short muscles hold them together. Lengthening bones is definitely a more complicated process than dealing with shells but not so bad that early life shouldn't be able to do it.

[Supermikhail]

Ah. I thought it worked the other way around. Hm. E: I mean, draw in through big opening, out through small. E: Current doesn't spiral - flagella move in a spiral, sort of like a screw propeller.

I thought an advantage to movement would be that there wouldn't be any still water in the place where flagella don't reach. Burger doesn't want to make sense.

Would it help if it had pores around the soft tissue and drew water in through them? Or it would be little different from what we have on Earth?

[Shoku]

Well yeah, I was thinking that a lot of little input pores in the sides and just a big 1 way jet shape might work, though if you want the buoyancy thing you'd need to hold gas somewhere or just ditch the heavy bony structure in favor of some other form.

[Supermikhail]

Aww. That's taking from the core of Burger, and if you take out the core, it's not Burger anymore.

I forget were there any other critters at this point that I could apply my newfound knowledge to? Oh. I hope Donutsaur and the Rooted... and the other recent fellow whose name I don't think we got... are still available.

[Shoku]

I thought you opted to wipe the slate clean. However, as loath as I am to rip off life on Earth you should be the opposite of reluctant to borrow off of those creatures.

We could borrow from donutsaur and the real world nautilus to make this thing buoyant- modify the frame the be the inner surface of the donut organ and then as it grows larger it seals off the inner portion with just a little tube reaching into it to control the gasses in there. If it had the cross section of a parabola it would keep a smooth shape after each compartment. The downside though, from ripping these forms off, is that it makes for a sketchy transition. The inner hole couldn't ever grow so they would either be quite limited in growth potential (not really bad for a species but bad for us playing with its form,) so it would be impractical to keep the feeding and propulsion hairs on the inner surface.

However! This is a fantastic opportunity to just give it a more complicated life cycle. While small it could have the hairs in the middle and move around as such but at some point just shed off that patch of cells and exist as a floating shelled creature that moved by some sort of flapping on the outer portion and ate- well, ate somehow. I don't have any ideas about how to put mouth parts onto this idea just now.

*the gas exchange thing I'm talking about would take a circulatory system which we haven't dealt with up to this point- it can't just automatically anti-leach the stuff, there's got to be some routing to get the buoyancy to work right with this.

...I'm going to have to draw this thing aren't I?

[Supermikhail]

Err. I don't know. I've got to think about it some. Plus, I've seen an animation of embryonic development, so that has to settle in. Why is gastrula's opening called "primitive mouth" (or something like that) if it's supposedly anal?

However, on an unrelated note, it turns out that Wikipedia has an article on hypothetical types of biochemistry.

[Shoku]

Warning: whole post is tl;dr material. Only for those interested.

Spoiler (click to show/hide)

It's anal for us. It is a mouth for insects.

Now if you think about the historic aspect of all of this it makes sense that we would watch insects and bug type things developing under the microscope first. With mammals they're hidden away in the female's organs so to really look at those you need to either just kill and extract them or figure out how to grow them outside of the mother. Reptiles lay eggs but they have opaque shells so you still have to figure a few things out to check that out- and then when you do you've got to figure out where to look on the yolk. Fish? Well they live in water. Yeah you could look at those fairly easily but there's not a lot of incentive either.
But bugs? A lot of them have minimalist eggs and they produce thousands and thousands of them. You barely even need to feed them and the eggs don't often have much extra going on to get in the way of what you're looking for.

So to get a little more to it. Drosophila was the species we went to first to figure out most of these things. It turns out they were a pretty bad example for the development of other organisms in a lot of ways but you can't know until you've looked. They do all of this funky weird stuff to get it done as fast as possible so that the meat they laid their eggs on might still be there for the maggots to eat when they hatch. They duplicate their DNA several times before they actually do any cell division- they make some little furrows that sort of lay out where the cells will be but they don't actually pinch them off from the original huge cell and- well, most things obviously don't do wacky stuff like that.

-

I don't think worrying about blastopores and whatnot will really be productive here. Like that video from awhile back said you could have giraffes and sheep and such develop their mouth first and get the same sort of animal, they simply don't because their ancestor didn't. The framework they build off of really needs to know which comes first and it would take too many changes to flip the order for no real advantage so it doesn't happen.

But even without that spiral cleavage and such don't seem like they will be helpful in working out what the creatures end up looking like.

[Supermikhail]

Hey, if the stuff you're talking about is specifically tl;dr only for those interested, I think there's no problem with spoilering that out.

Again, on an unrelated note, sponges are awesome. I am almost convinced now that you were wrong about high biology knowledge hurting creative process. I mean there's so much crazy stuff inside them, and glass sponges... Like, there is really no problem with making a skeleton, they grow the beginnings of it in all shapes and forms, and photo-sensitivity appears to be pretty universal, although I didn't learn that from sponges. My frustration before, besides all other reasons, came from not knowing that you can get away with putting so much crazy stuff in, twisting shapes like that. All I knew about was mammal development. Now I'm almost ready to become a god, after I draw some other stuff, though.

[Shoku]

Because the background isn't dark I forget that tag is even there~

I was worried you were going to go through the whole tree of life before you felt lik you could contribute again.
I still stand by saying that I know too much but when we get a website rolling I should probably work out some primer to give people a little more to work with. The forcing a jellyfish along worm evolution lines thing was one way I hoped to figure that out but you don't seem interested.

[Supermikhail]

I'm interested. I'm just busy with a couple of things which I've been promising to myself for a while to finish promptly and then devote my time to other affairs including this project. Also, I've realised what has changed since the time of Burger. My notebook ended and I don't have a suitable replacement for it, so I don't have anything to put my travelling inspirations down in. Also, my University work has moved closer to my home and has become more intermittent to the point of my staying at home constantly last month translating articles. So, kind of bad time.

Also, sponges are awesome. Today I've read about their reproduction and Trichoplax. I've should have tried entering into Biology so hard. Oh well.

[Shoku]

You'd need to be careful and check out the emphasis of biology programs. Mine was mainly cell biology and biochemistry so I only had a few classes that really went into body plans and the other sorts of things that interest me. Though even most scientists rarely deal with the actual diversity of life. We chose model organisms from each group so all the groundwork of figuring things out at first happens with those animals and then if somebody has a good reason to look at some other species they start off with the understanding from the model organism and usually just work out how their target species is different.

You have to be able to write a good paper for why you want to study some particular thing to get the money for it so I'm pretty sure most schools focus on teaching students about those model organisms and the tools you would use in a laboratory setting (or rather the history of the tools used currently.) It takes quite awhile to get access to more than an overview class for ecology and there's barely any room for exploration type endeavors.

Edit: So I should prepare the jellyfish exercise? What we create there won't be any part of the world for this.

[Supermikhail]

Yeah, being an amateur is much cooler. I always remember Sherlock Holmes when I'm feeling down.

Er. I remembered why I'd delayed the jellyfish exercise - I haven't gotten to them in my book yet. I've just started Eumetazoa, and I'm convinced that there's nothing primitive there, so I'm not prepared to take this exercise light-heartedly.

In other news, I'm awesome.

It seems that I am unable to explain what's going on in this picture coherently, see what you can make out, and I'll fill in the blanks. But I can assure you that this is awesome. Also, three-sexual reproduction (with the participation of another species).

[Shoku]

Swimmy tubes join into a balloon and then reproduce with their young carrying offspring of the balloon off into the currents and they all wander away from each other.

I've gone over why there are two sexes before in some block of text or other. If you want your offspring to have a good shot at survival you make lots of small ones or you make not so many big ones. While you could form a chain of hermaphrodites so that there were technically some sort of threesome going on there would be no particular genetic benefit. It's a big enough bother finding one mate much less two so this sort of thing would impose a much harsher limit on solitary lifestyles for descendants preserving the 3 sex system.

[Supermikhail]

Er. But there are three swimmy tubes with different DNAs. Wouldn't it be beneficial for the tubes to have 3 sexes? Granted for most of their lives they would live and mate with the same two partners, but when the offspring wander off they settle with different DNAs.
I guess that could work with two sexes, too.
And the balloon could use a form of sexual reproduction.