Flatworms, Nematodes, Annelids, Marine Worms Flatworms, Nematodes, Annelids,

General Characteristics of Marine Worms Bilateral symmetry Cephalization (Has a head)- Has a nerve net that concentrates around the head Head has eyespots that are sensitive to light Hydrostatic skeleton (no bones) most are benthic

Platyhelminthes (Flatworms) General characteristics Acoelamates- having no body cavity No segments, No circulatory system, No Respiratory system (get nutrients and oxygen through diffusion Has 3 true body layers, endodermis, epidermis an mesoderm Flame cells used for excreting waste Ciliated body

Flatworms Most turbellarians are Carnivorous Chemoreceptors to detect prey unique prey-capturing mechanisms Stab__ Suffocate_ pharynx secretes enzymes and pulls in food food is digested in the gastrovascular cavity which functions as a mouth and an anus. Flat worm hunts Crab https://www.youtube.com/watch?v=cOJqbqESoG0

Flatworms Reproduction _Asexually through regeneration _Sexually_: Flat worms are hermaphrodites. They produce both egg and sperm but do not self fertilate

3 Types of platyhenthisis 1. Turbellarians (Non Parasitic) Planarian, Can regenerate itself if cut into. Leopard flatworm worm https://www.youtube.com/watch?v=zCH37KI_R_E

Parasitic worms (flukes and tapeworms) 2. Cestoda,(tapeworms) – Paracidic, live in the intestine of animals and humans. Can grow to be over 100 feet long The scolex is the head with suckers or barbs to attach to the hose. Proglottids are individual body sections that separate from body and carry fertilized eggs. NO digestive system http://www.oprah.com/oprahshow/Dr-Oz-on-Why-Tapeworms-Are-the-Mother-of-All-Parasites-Video

Life cycle of a fish tapeworm

Flukes 3. Trematoda (flukes) such as blood flukes small flat worms which are internal parasites of mollusks and vertebrates have a complex life cycle of at least 2 hosts. https://www.youtube.com/watch?v=N6HOhEvsH2k

Nematodes _round worms, tapered at both ends _No segments___ _They have a body cavity_: Hence why round in shape __Most numerous animals on the planet__ Handful of sediment may contain 3 million nematodes http://www.youtube.com/watch?v=gofmShLJIPM&safety_mode=true&persist_safety_mode=1

Nematods Nonparasitic species are scavengers and are small in size__ Parasitic and carnivorous species are larger_:

Annelids Bodies divided into _Segments_ Has _a closed circulatory system__ “more advanced” worm Setae: used for locomotion and defense Polychaetes (Not a bird)  are the main type of marine worm: For example, earthworm is an annelid, but it is not a polychaete ↑ common marine polychaetes ↓ deep sea vent tube worms

Annelids Polychaetes Annelids 2 Types: ← errant polychaete featherduster→ Annelids Polychaetes Annelids 2 Types: _Type 1: Sedentary polychaetes that burrow or built tubes of sand, calcium carbonate, proteins. They filter feed_with cilia that extend from tubes and the aid of chemoreceptors.

My Favorite Sedentary Polychaetes: _Christmas Tree Worms_; Also used in Avatar; IN Real Life Use their gills to capture plankton

As seen in Avatar Christmastree worm https://www.youtube.com/watch?v=eS8OYF7isCU https://www.youtube.com/watch?v=lf4Eb89538c

Polychaetes Annelids 2 Types: Type 2: _Errant (swim)_polychaetes have jaws with teeth_ and nocturnally hunt small invertebrates. Many are poisonous and have a painful bite.

Sexual Reproduction in Polychaetes _Epitoky_ is a form of reproduction ,The worms undergo a transformation into an _Epitoke, a pelagic morph capable of _Sexual Reproduction. Often an epitoke is the end part of the worm, which separates from the head. The end then releases the eggs or sperm. .

Other Marine Worms _Peanut Worms_: Filter Feeder that burrows in the sand, sticking out its head to feed

Other Marine Worms _Spaghetti worms__: lies hidden in sediment or rocky crevices while its food-gathering tentacles wave overhead.

Other Marine Worms Fire worms have bristles that are filled with venom and easily break when touched to discourage predators. They also inflict a painful rash on any human who handles them

Aliens or Marine Worms? New Species, of marine worms Yet still to be named……..

Marine Worms Name the three types/classifications of worms List them from simple to complex List three characteristics of each type of worm Give two examples of sexual reproduction for worms Describe two ecological roles of marine worms. What is swimmers itch? Define: Sedentary, Cephalization, Benthic, Errant, Polychaete and gastrovascular cavity 7.