ZOO 2700 Lecture Notes - Lecture 10: Anatomical Terms Of Location, Flame Cell, Turbellaria
15 Feb 2018
School
Department
Course
Professor
Document Summary
Platyhelminthes: ~20000 species, aka flatworms, dorsoventrally flattened, ~70% parasitic. Apomorphies: multi-ciliated epidermis and gastrodermis, protonephridia (2 cilia per terminal cell, negative pressure, flame cell: characterized by 2 cilia or more in flatworms only 2, solenocyte: terminal cell with one flagellum, hermaphroditic. Longitudinal muscle: dorsoventral muscle, muscular waves swimming. Showed that you could cut the flatworm into a maxiumum of 279 pieces - and eachone would grow into a new planarian. Likely even totipotent (differentiation into all zygotic cell types + extraembryonic tissues: pluripotent: ability to differentiate into all zygotic cell types, adult stem cells, transplantation of a single neoblast into a lethally irradiated (=stem cell depleted) worm rescued. In other systems, exist only transiently during early embryonic development the recipient and gave rise to a perfectly healthy animal of the donor genotype. Statocysts gravity receptor (?: ciliary receptors, mechanoreceptor, chemoreceptors. Apomorphy: neodermis: adaptation to parasitic life style, protection from gut enzymes, absorption of nutrients from host, non-ciliated, adult.
