AKA Flukes (they tend to be internal parasites on animals with a back bone- vertebrates)

Parasites

similar to Planarians but do not have eyespots 

Much of body is filled w/ reproductive organs - hermaphroditic 

Tape worms (gastrointestinal issues)

Parasites 

Often pass through several different hosts 

Hermaphrodites

Phylum Platyhelminthes  

Segmented worms

complete gut

bilateral symmetry 

circulatory system 

Coelomate within segments- coelomate means that a membrane covers the organs in a secondary body cavity

Earthworms and freshwater worms 

Have chaetea but no parapodia 

Terrestrial and freshwater 

Hermaphrodites 

Leeches 

External parasites of vertebrates 

Used in medicine to reduce swelling in reattached fingers, toes and other body parts 

Hermaphrodites 

§  Most have a foot, mantle, gills, and a radula

§  Have open circulatory system

§  Respiratory system

§  Most have shell, shells or tooth

§  Have the most intelligent of invertebrates in the class Cephalopoda

§  Have eight plates on dorsal surface

§  All marine

§  Use radula to scrap off algae from rocks

§  Have two shells

§  Most are filter feeders with siphons (tubes that suction something)

§  Snails and slugs

§  Have radula

§  Most have coiled shell, but some do not

§  Carnivores and herbivores

§  Have a single shell

§  Contain some of the smartest of the invertebrates

§  Tentacles around the mouth

§  Use a siphon for movement

§  Squid and Octopus and cuddle fish

·      Have a cuticle or exoskeleton which must be molted for the organism to grow

·      Are protostomes which means they share a similar early developmental pattern and other traits; for example, they have a ventral nervous systems and the first embryonic opening becomes the mouth

§  Thick cuticle that sheds four times in their life

§  No circulatory system but oxygen and food exchange through cuticle and intestines

§  Abundant in soil

§  Psuedocoelomate

§  Trichinella spiralis causes trichinosis

§  Caenorhabditis elegans highly studied by genetics

§  Vinegar eels are free living

§  Exoskeleton of chitin

§  Jointed appendages

§  Extreme cephalization with well developed sense organs

§  Compound eyes

§  Circulatory system and respiratory system

§  Centipedes

§  One pair of legs per segment

§  Carnivores with venom in jaws

§  Millipedes

§  Two pair of legs per segment

§  Herbivores and scavengers

§  Not venomous, but can have chemical defenses which are toxic

§  Head, thorax and abdomen

§  Single pair of antenna

§  Three pairs of legs attached to thorax

§  Respire by means of tracheae straws

§  Circulatory system

§  Wings

§  Some have metamorphosis (caterpillar to butterfly)

§  Many are important as pollinators, crop eaters, disease vectors, and food for other animals

§  Spiders, scorpions, ticks, fleas, mites, and horseshoe crabs (their blood is blue and used in the pharmaceutical industry) 

§  Cephalothorax and abdomen

§  Four pair of walking legs

§  Chelicerae – specialized mouth parts

§  Body divided into head, thorax and abdomen

§  The head parts are fused; the other sections may be made up of segments

§  Some have a covering called a carapace, e.g. crayfish

§  Usually have two pair of antenna – two are longer and two are shorter – antennules 

§  Shrimp, lobster, crabs, isopods, copepods and barnacles