2.  An invertebrate is an animal without a backbone.  The group includes 95% of all animal species

3.  There is no escaping the invertebrates!  Sharing space on your face

4.  Animals are distinguished by their body cavity or lack of.

5.  Acoelomates › lack a body cavity (coelom) › bilateral symmetry › one internal space, the digestive cavity

6.  Coelomates  have a body cavity(s)  Digestive system and body wall can move independently  Internal organs can be more complex  Coelomic fluid can assist with respiration, circulation, excretion

7.  The good the bad and the ugly!!!

8.  Phylum Porifera  Phylum Cnidaria  Phylum Platyhelminthes  Phylum Mollusca  Phylum Annelida

9.  Phylum Porifera  Sponges  Sessile aquatic animals  Some are freshwater species, most are marine  shapes of their bodies are adapted to maximize the efficiency of the water flow

10.  Phylum Cnidaria › (pronounced nidaria/ with a silent c ) › phylum containing over 9,000 species of animals found exclusively in aquatic and mostly marine environments  Jellyfish  Hydra

11.  Phylum Cnidaria  Two basic body forms are seen : swimming medusa and sessile polyps

12.  Phylum Cnidaria › Their distinguishing feature is a cnidocyte, specialized cells that they use mainly for capturing prey.

13.  Phylum Cnidaria  Have no brains or central nervous systems  Instead they have nerve nets that generate signals in response to various types of stimulus, such as odors

14.  Phylum Platyhelminthes  Flatworms › Planarian › Fluke › Tapeworm  no specialized circulatory or respiratory organs  Over half of all known flatworm species are parasitic, and some do enormous harm to humans and their livestock oxygen and nutrients to pass through their bodies by diffusion

15.  Phylum Platyhelminthes Taenia solium

16.  Phylum Mollusca › Considered coelomates  Coelom is limited to space around the heart

17.  Phylum Mollusca

20. › Respiratory system –gills › Digestive system – starts with Radula

21.  Phylum Mollusca

23. Cool Squid Stuff to look for During dissections

24.  Phylum Annelida Segmented Most have a pair of coeloms in each segment which allows independent movement Coelomatic fluid *Moist environments

25. › Phylum Annelida › Respiratory system  ( usually) no specialized organs for gas exchange  Thin, permeable body wall – surface for gas exchange › Digestive system  complete digestive system, with mouth and anus  digestive tubes of earthworms have special structures, like a muscular wall and a gizzard-peristalsis

26. › Phylum Annelida › Nervous system  two ventral nerve chords  one relatively big nervous cell concentration › Circulatory system › Closed › Move by peristalsis -waves of contractions and expansions › 2 main vessels  Dorsal moves blood anterior  Ventral moves blood posterior 10X magnification

27. › Phylum Annelida › Reproductive system – Varies  Asexual-budding  Sexual  Earthworms  hermaphrodite

28.  Phylum Annelida  support terrestrial food chains both as prey  aerating and enriching soil  Minnesota?  Leeches ?

29.  Dissecting the earthworm  FOLLOW DIRECTIONS in your lab book  Allow 20 minutes