ZOO 2700 Lecture Notes - Lecture 19: Gonochorism, Chaeta, Nemertea
28 Mar 2018
School
Department
Course
Professor
Document Summary
Lecture 19: nemerteans: 10-20m long, extremely predatory, important for marine ecosystems, ambush predators: hang out under rocks/algae and wait for prey to come by and jump them, toxicate and eat them whole. Apomorphies: rhynchocoel: fluid-filled chamber; balloon shaped, press it together and it elongates, proboscis, no chaeta. Muscle layers: allows them to move in their environment. Can move quite quickly and have a lot of control of their body. Only a few species that have 2 muscle strands (circular and longitudinal) Neurotocins: surrounding glands in the proboscis (does not contain toxins) Brain: one of the most distinct features of proboscis. Coelomic circulation: anterior to posterior, dorsal to ventral, allows organism to breathe. Supported by the musculature: 2 important functions: allows circulation to occur efficiently in the organism, locomotion. Most terrestrial environments there are larvae but in low abundances- more common in aquatic. Larva- indirect development: developmental stages are very different to what they become: these larvae are rarely reproductive.
