BIOL 1080 Lecture Notes - Lecture 11: Bryozoa, Parapodium, Acorn Worm
Document Summary
Invertebrates: animals without a backbone are known as invertebrates. Those with a backbone are vertebrates: about 97% of all animals are invertebrates, all major animal groups (or phyla) have representatives in the marine environment. Flagella create a water current that brings in food particles: collar on choanocyte traps food particles, pinococyte- flattened cells that cover exterior of body, pore cells (porocyte)- cells with a pore to allow water to pass into body. Used for protection and feeding: digestive system is incomplete (sac-like with mouth only, nerve net throughout body coordinates movements. Some jellyfishes also have sensory cells and contractile cells: reproduction, sexual- (different patterns) In some cnidarians: medusa is the sexual stage. Fertilized egg results in a zygote, which develops into a swimming larva, the planula: the planula settles on the bottom to form a colony of polyps, new madusae are formed by mature colony, asexual, polyps reproduce by budding.
