Is a flatworm a cnidarian?
Cnidarians are diploblastic, whereas Platyhelminthes are triploblastic. Platyhelminthes possess bilaterally symmetrical, soft, worm-like elongated bodies, whereas cnidarian possess radially symmetrical, soft, medusa-like or polyp-like body forms.
How do flatworms differ from cnidarians and porifera?
Porifera (sponges) have specialized cells and an endoskeleton but lack true tissues and body symmetry. Cnidaria (jellyfish and corals) have tissue-level organization and radial symmetry. Platyhelminthes (flatworms) have a mesoderm cell layer, simple organ systems, cephalization, and bilateral symmetry.
When did Cnidaria first appear?
about 580 million years ago
Is Cnidaria extinct?
Not extinct
How fast can nematocysts trigger?
They show discharge kinetics of nematocysts in Hydra to be as short as 700 nanoseconds, creating an acceleration of up to 5,410,000 g.
What triggers a Nematocyst to activate?
The cell’s thread is coiled under pressure and wrapped around a stinging barb. When potential prey makes contact with the tentacles of a polyp, the nematocyst cell is stimulated.
What are the three types of nematocysts?
There are three main types of cnidae: nematocysts, ptychocysts, and spirocysts, with many variations. Depending on the species, one or more types may be on the organism.
Do all cnidarians have nematocysts?
Nearly all (about 99 percent) cnidarians are marine species. Cnidarians contain specialized cells known as cnidocytes (“stinging cells”) containing organelles called nematocysts (stingers).
Why are cnidarians considered simple but deadly?
Why are Cnidarians considered simple but deadly? They are simple bodied creatures but have deadly stingers that can cause serious pain to us, or in rare cases, death if the sting is severe.
Can Vegans eat jellyfish?
No, vegans can’t eat jellyfish because they are animals. Veganism refuses to consume any animal. But since jellyfish don’t have a brain or heart unlike any other animals, several people consider them to be plant as they are unable to feel pain.
Can Vegans eat plankton?
Is is marine phytoplankton vegetarian and vegan ? Yes, they are 100% vegan! Many people get confused by hearing the word ‘plankton,’ which is the name for a vast genus of creatures that have no power to move themselves but are borne along in the currents.
Why are oysters not vegan?
Apparently, some make an exception for oysters. Oysters also don’t have a central nervous system, so the theory is that they do not feel pain like we or other animals do. So while milk, eggs, and even honey are excluded from a vegan diet, some people make exceptions for this popular bivalve.