1. Trying to remember all those phyla!
Invertebrates Review
Trying to remember all those phyla!

2. Porifera sessile (don’t move) with porous bodies
Lack tissues and organs (no nerves or muscles)
Filter feed by drawing water through pores
Choanocytes: cells ingest bacteria and particulate food suspended in the water
Ex. Sponges!

3. Cnidaria Radial symmetery a gastrovascular cavity (one opening)
Carnivores: possessing tentacles armed with cnidocytes (stinging capsules) that aid in defense and capture of prey
Two body forms: sessile polyps and floating medusas
Ex. Hydras, jellies, sea anemones, coral

4. Ctenophora Comb jellies possess rows of ciliary plates for locomotion
Use retractable tentacles to catch food
Tentacles bear adhesive colloblasts
When prey contact a colloblast it releases a sticky thread that will capture the food
Tentacle is then wiped into the mouth! Yum!

5. Platyhelminthes Acoelomates with gastrovascular cavities Triploblastic
Tapeworms lack a digestive tract altogether and absorb nutrients across the body surface
Triploblastic
Ex. Flatworms (planaria!), flukes, tapeworms

6. Rotifera Tiny animals that mainly inhabit freshwater
Multicellular and have specialized organs
Complete digestive tract
pseudocoelomates with jaws and crowns of cilia that draw water into the mouth
Parthenogenetic: females can produce more females from unfertilized eggs

7. Lophophorates Coelomates
Lophophore: a horeseshoe-shaped, suspension-feeding organ
bears ciliated tentacles that surround the mouth
Ex. Bryozoans – colonial organisms that live on reefs
Ex. Phoronids – tube-dwelling marine worms
Ex. Brachiopods – looks like a clam

8. Nemertea Proboscis worms are named for their prey-capturing apparatus
Unique retractable tube used for defense and prey capture
Acoelomate, but contains a fluid filled cavity
Complete digestive tract and a closed circulatory system (blood is in vessels)
Ex. Proboscis worms

9. Mullusca Muscular foot: used for movement
Visceral mass: contains internal organs
Mantle: fold of tissue that secretes a shell
Most have separate sexes, but many snails are hermaphrodites,
Ex. Snails, slugs, oysters, clams, octopuses, and squid

10. Interesting! 

11. Annelida Segmented worms, with a Coelom
Have a digestive tract, blood vessels, and nerve cord that run the length of the animal
Closed circulatory system: network of vessels contain blood with oxygen carrying hemoglobin
Skin used for respiration
Metanephridia: excretory tubes
Hermaphrodites but cross fertilize
Ex. Earthworms and leeches

12. Nematoda Roundworms: nonsegmented pseudocoelomates
Tough exoskeleton – cuticle - covers the body
Complete digestive tract, but lack a circulatory system
Sexual reproduction

13. Arthropoda Segmentation
Hard exoskeleton: cuticle – constructed from layers of protein and chitin
Jointed appendages
Well developed sensory organs: extensive cephalization
Open circulatory system: organs bathed in hemolymph
Ex. Spiders, ticks, scorpions, millipedes, mites, centipedes, insects, crabs, lobsters, shrimp

14. Echinodermata Sessile or slow moving Radial adults, bilateral larvae
Water vascular system, a network of hydraulic canals branching into extensions called tube feet function in locomotion, feeding, and gas exchange
Sexual reproduction
Ex. Sea stars, sea urchins, sand dollars, sea cucumbers

15. Checking for Understanding #1
Which phyla is characterized by animals that have segmented bodies?
A. Cnidaria
B. Platyhelminthes
C. Porifera
D. Arthropoda
E. Mollusca

16. Checking for Understanding #2
Although a diverse group, all cnidarians are characterized by ______.
A. a gastrovascular cavity
B. an alteration between a medusa and polyp stage
C. some degree of cephalization
D. muscle tissue of mesodermal origin
E. the complete absence of sexual reproduction

17. Checking for Understanding #3
A land snail, a clam, and an octopus all share ________.
A. a mantle
B. a radula
C. gills
D. embryonic torsion
C. distinct cephalization

18. Checking for Understanding #4
Which of the following is NOT a characteristic of most members of the phylum Annelida?
A. hydrostatic skeleton
B. segmentation
C. metanephridia
D. pseudocoelom
E. closed circulatory system