BIO153H5 Lecture Notes - Lecture 15: Arthropod, Lophophore, Trochophore
Document Summary
Cnidarians: diploblastic, radially symmetric, have nematocyst that is at one of their tips that is basically their weapon. From the triggering and the expansion into the tread happens w/in nanoseconds. One of fastest and most violent processes. Once trigger released - that"s it - not able to be curled back in and reused. What about success: many new body plans evolved during cambrian explosion, cnidarians have been radially symmetric and diploblastic since 560 million years, are they therefore less evolved or less successful> Successful bc they have managed to survive for this long. Lophotrochozoans: include a wide range of body plans, their names comes from a feeding structure and a larval form. Not all groups have these ^ but most do. Still in search for why they appeared: there are a variety of web forms and functions. Flexible but also resistant to tearing up completely. A spider can produce different types of silk - typically 5.
