KINGDOM ANIMALIA Protostome Development Deuterstome Development Radial Symmetry Bilateral Symmetry Cellular Level Organization Tissue Organ Level Organization Phylum Annelida The Segmented Worm 1 Classification Class Polychaeta Most are marine biloped parapodia on each segment Exhibit epitoky or others are dioecious Externally fertilized eggs develop into ciliated trocophore larva indirect development Class Oligochaeta Class Hirudinea terrestrial forms are important nutrient recyclers and soil aerators Their eyes are called epithelial sense organs Monoecious Hermaphrodites exchange sperm The clitellum then is releases and becomes a cocoon No internal septa No Setae Posterior sucker attaches to host Anterior sucker used for sucking host s blood body fluid Their Clitellum is only evident during reproduction Release aneasthetics antibiotics and anticoagulants Protostome Triploblastic endo meso ectoderm Eucoelomate with schizocoelous formation Determinate spiral cleavage 2 Organization Organ Level 3 Embryonic Development 4 Symmetry 5 Skeleton Support Bilateral Anterior Posterior Dorsal Ventral Cephalization Concentration of sense organs nervous control etc in the anterior end of the body Hydrostatic Skeleton Aciculum supporting structure in notopodium and neuropodium sections of the parapodium of some polychaetes 6 Movement Locomotion 7 Sensory Nervous System Longitudinal and circular muscles peristaltic concertina motion Setae aka chaetae chitinous bristles on all annelids except leeches Cerebral Ganglion Ganglion per body segment Ventral nerve cord The Nervous system includes a cephalic ganglia brain that is attached to the double ventral nerve cord the run the length of the animal there are additional ganglia and nerve branches repeated in each segment 8 Digestion Feeding Complete with regional specialization and peristalsis Polychaeta eversible turns outward or inside out pharynx esophagus esophageal caeca jaws Oligochaeta muscular pharynx esophagus and gizzard typhlosole U shaped intestine increases surface area for absorption Annelids have a complete digestive track The gut is often modified into region specialized for different tasks ex buccal cavity pharynx esophagus crop gizzard Beard Worms part of polychaetes have no digestive track 9 Excretory Osmoregulation Metanephridia these tubules in each segment collect filter coelomic fluid removing nirtogoneous waste Nitrogenous Waste products are often excreted into the coelomic fluid before being passed to the outside by nephridia Gas exchange occurs through diffusion across the body wall through modified gills 10 Circulation Closed circulatory system Contractile vessels hearts Dorsal blood vessel to heart Ventral blood vessel away from heart Extracellular hemoglobin carries O2 Diffusion 11 Respiration 12 Reproduction Polychaeta most are marine Some dioecious trochophore larvae Indirect development externally fertilized eggs The trochophore fertilized egg undergoes spiral cleavage and the blastula develops into a ciliated trochophore larva Some polychaeta exhibit epitoky no permanent gonads gonads form only during the breeding season and usually in posterior segments Atoke non sexual form or part of polychaete Epitoke sexual part of form of polychaetes Oligochaeta Typically monoecious clitellum Hirudinea Typically monoecious hermaphrodites Terms blastocoel 1 Schizocoelous Part of protostome development when mesoderm emerges from within the 2 Metamerism The body is a series of repeating segments or metameres 3 Septi Separate metameres internally 4 Annuli Separate metameres externally by circular rings 5 Prostomium Peristomium the anterior head of adult annelids are comprised of these parts 6 Pygidium Tip of annelid bearing the anus new metameres form just in front of the pygidium 7 Aciculum A chitinous support rod in parapodium with oblique muscles attached to it 8 Parapodium notopodium and neuropodium Paired Paddle like appendages in marine polychaetes they contain setae on the tips 9 Pharynx The part of the alimentary canal immediately behind the mouth in invertebrates 10 Crop is a thin walled expanded portion of the alimentary tract used for the storage of food prior to digestion 11 Gizzard specialized stomach contructed of thick muscular walls used for grinding up food 12 Nephridiopore pore that releases the waste that was collected from the metanephridia tubile which filter the coelomic fluid 13 Phylum Pogonophora Beard worms formally in their own phylum Pogonophora Now they are considered a clade within the class Polychaeta some live in marine sedaments and others are found in deep see associated with geothermal hydrothermal vents at 2600 meters depth They have no digestive track something usually associated with gut endoparasites Eating occurs either by small tentacles moving food and allowing it to absorb dissolved organic material or in larger species a trophosome is loaded with symbiotic mutualistic chemosynthetic bacteria that use sulfer oxidation methane and sulfide to supply their annelid host with organic nutrients These organism are Dioecious 14 Phylum Echiura this phylum exhibits no sign of segmentation descendants of polychaete annelids commonly called spoon worms constantly extended have a spoon shaped proboscis live in U shaped burrows or rock coral dioecious external fertilization trochophore larva closed circulatory system no heart pairs of nephridia ventral nerve cord and nerve ring no brain Concepts 1 Understand how segmentation allows concertina movement in Annelids Longitudinal and circular muscles allows Annelids to have peristaltic concertina motion The muscles in the body wall allow metameres to move independently resulting in more complex and variable forms of locomotion 2 Understand the formation of the coelom in schizocoely As protostomes annelids have schizocoelous coelom formation In this type of formation schizocoelic coelom develops as a split in the embryonic mesoderm 3 Understand the challenges and benefits of living in deep sea vents In deep sea vents there is no sunlight There is still an ecosystem of animals These vents excrete chemicals that little animals eat and then bigger animals can eat the little animals creating a food web that was never believed to exist before Images 1 Class Polychaetes 2 Class Oligochaetes 3 Class Hirudinea leeches Phylum Platyhelminthes Flat worms 1 Classification Class Turbellaria Marine Freshwater swim by epidermal cilia Others glide over slime track secreted
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