00:01
Many traits in the animal kingdom develop as you go through the phylogenies, starting with the simplest invertebrate group, the sponges or periphera, and moving through more complex groups like the chordates.
00:16
So some minimum amount of traits need to be present to be considered an animal.
00:22
And then as the different invertebrate groups evolved, the traits become progressively more complex.
00:29
So the first trait that really had to evolve is being multicellular.
00:34
And that trait is found in periphera, nideria, plattie helmints, which are flatworms.
00:45
And then the nideria group include the anthozoa, the hydrozoa.
01:04
The plattie helmints group includes turbolaria and sestota.
01:12
So multicellular is kind of one of the minimum requirements for being an animal.
01:18
Another is the presence of collagen.
01:21
It's a very common protein in animals.
01:25
So periphera, nideria, which includes the anthozoa, the hydrozoa, and the platy helmints, which includes the turbolaria and the cestodes.
01:37
Now the first trait where you're going to see some groups diverge is the presence of tissue.
01:44
So the only group that has no tissue are the sponge or peripher group.
01:49
The rest of the animals have tissue.
01:53
The sponges are the only ones that lack epithelial tissue.
01:58
So this is going to be present in the nideria, anthezoa, hydrozoa, and the platy helmets, turbolaria, sestota.
02:12
Symmetry is the arrangement around a central axis, and that is present in the nideria.
02:25
Bilateral symmetry is the presence of two distinct sides.
02:30
That's in the platy helmorphs, which includes the cestodes and the turpul area.
02:40
Diploblastic and triploblastic relate to having a certain number of tissue layers.
02:46
So diploblastic are two layers, and that's in the periphera and the nideria.
02:56
Triploblastic is the platy helmorphs, which include turbillaria and sestota.
03:09
The presence or absence of a body cavity.
03:13
If you're acilomate, you don't have it.
03:16
And the organisms, periphera, nideria, plattie helmints are all acilament.
03:31
None of them have acilum.
03:33
So this would be absent in all of that.
03:39
Nidocytes are a defining characteristic of the nideria group.
03:42
They're the stinging cells that use to capture prey, so they're in the nideria.
03:50
Broadcast reproduction is very common in sessile invertebrates...