SLE204 Lecture Notes - Lecture 5: Internal Fertilization, Hindbrain, Triploblasty

• School: Deakin University
• Department: Science, Engineering and Built Environment
• Course: SLE204
• Professor: Anneke Veenstra

Document Summary

Chordates all have: notochord (at some stage in lifecycle, bilateral symmetry, anterior/posterior axis, cephalisation, coelom, metamerism, complete digestive tract, triploblastic. 5 chordate features: notochord internal rod-like structure. Provides support & shape for body; sites for muscle attachment. V-shapes muscles lateral flexion: dorsal hollow nerve cord. Coordination of movement: post anal tail. Movement, propulsion: pharyngeal clefts (gill slits) Filtration filter out food particles; filter feeding. Secretes mucous to pick up food particles. Subphylum urochordata (cid:862)tail chordates(cid:863) e. g. ascidians, sea squirts, tunicates. Class ascidiacea: free-swimming larvae (tadpoles); sessile adults, all 5 features in larval organisms; loses notochord and dorsal nerve cord as adult, filter feeders, adults have inhalant and exhalent siphon + pharynx with gill slits. **complex digestive system*: notocord and nerve cord persist throughout life, also have structures suggesting a vertebrate plan: More advanced circulatory system closed circulatory system; no heart; colourless blood: no teeth or eyes -> not a predator.