1. JP Keller, Ryan Peterson
Invertebrates
JP Keller, Ryan Peterson

2. Sponges Over 9,000 species Simplest creature known to man
Live mostly in the oceans and seas
Simplest creature known to man
Phylum- Porifera
Sponges reproduce both ways
Sexually- Sperm and Egg released into water
Asexually- Budding

3. Body of a Sponge They are not symmetric
They don’t grow from a central point
Their cells are not organized into tissues and organs
Individual cells can grow through a membrane

4. How a Sponge Eats Collar cells pump water through sponge
One cubic centimeter of sponge can pump 20 liters of water a day
The collar cells also trap food
The water is filtered to gather tiny animals and protists for food

5. Cnidarian- Carnivores
They have symmetry and are called true animals
Also called Eumetazoans
Embryonic stage
Three different levels of tissue
Ectoderm- outer body and nervous system
Mesoderm- skeletons and muscles
Endoderm- digestive organs
Phylum-Cnidaria, includes jellyfish, hydra, corals and anemones
Other phylum- ctenophore, includes comb jellies and delicate marine animals

6. Radially Symmetric Body parts arranged around central point
Stinging cells- Cnidicytes, no other organism has these, this is where the phylum name comes from
Small barbed harpoon, called a nematocyst

7. Eating and Reproduction
Food trapped by a Cnidadore is introduced by endocytosis and it is digested intracellularly
Sexually
Larvae find a spot to become a polyp
Polyp strobilates
Juveniles become mature
Asexually
They can either bud like sponges or divide themselves

8. Body Shape Medusa- gelatinous, free floating and umbrella shaped
They are the most common
Polyps-cylindrical pipe shaped and normally attached to rocks

9. The Evolution of the Body Cavity
Bilateral symmetry
Left and right halves are symmetric
Top is called the Dorsal
Bottom- Ventral
Front-Anterior
Back-Posterior
Definite head
Move around head first
Sensory organs are here to detect food, mates, and possible danger

10. Nematodes
Pseudocoelom- body cavity between the endoderm and the mesoderm
Many advantages
circulation- allows for quick movement of fluid
Movement-fluid in body cavity makes body rigid for muscle driven boy parts
Organ function- organs can function without muscle interference

11. Key Characteristics Mainly parasitic
Includes tape worms
Only bilaterally symmetric animals that don’t have a body cavity
Reproduce sexually
Occurs through the exchange of sperm

12. Other Important Information
One way gut
7 animal phyla have a pseudocoelom
Only one has large amount of species
Nematode
Nematodes- round worms
500, ,000 species
13,000 named
One spade of dirt- 1 million nematodes

13. Even More Important Information
Phylum- platyhelminthes
20,000 species
Mostly flat worms
Simplest animal with organs
No internal body cavity
No circulatory system
Only one opening
Mouth food enters and exits

14. More on Nematodes Some can be parasitic, infect humans
Layer of muscle extends the length of body
Beneath a flexible thick layer of epidermis and cuticle
Muscle pushes against the cuticle and pseudocoelom to move worm

15. Mollusks Largest phylum except for arthropods
Over 100,000 species
Body cavity called a Coelom
Fluid filled cavity in the mesoderm
They have primary induction- one layer interacts with another
Physical contact of mesoderm and endoderm
Least advanced because their bodies aren’t segmented

16. Other information about the fascinating mollusk
They have a circulatory system that move nutrients, oxygen, and waste
a circulatory system is a system of vessels that carry fluids to every part of the body
The heart(s) power this system
They’re called the most successful land animals
35,000 terrestrial mollusk species

17. Physical Characteristics
Three main body parts
Visceral mass- central section that contains organs
Mantle- heavy fold of tissues around the visceral mass
Gills in aquatic snails
Simple lungs in terrestrial
Every mollusk has a muscular foot!!

18. Mollusk Reproduction Almost all mollusks reproduce sexually
There are both male and female mollusks