Section 281 Sponges Sponges were once classified as plants Asymmetrical Lack tissues and organs Cell recognition makes them animals The Simplest Animals Sponges belong to Phylum Porifera System of pores ID: 779032
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Slide1
Ch. 28 – Simple Invertebrates
Slide2Section 28.1
Sponges
Slide3Sponges were once classified as plants
Asymmetrical
Lack tissues and organs
Cell recognition makesthem animals
The Simplest Animals
Slide4Sponges belong to Phylum
Porifera
System of pores
OstiaPores that let water into spongeOsculaPores that let water exit
Larger than ostiaSessile
The Simplest Animals
Slide5Prevent sponge body from collapsing on itself
Composed of spicules
Tiny needle composed of silica or calcium carbonate
Some sponges contain sponginFlexible protein fiber
Sponge Skeletons
Slide63 Types of Sponges Based on Their Skeleton
Calcareous
Spicules composed of calcium carbonate
GlassSpicules made of silica
Demosponge
Spongin
Types of Sponges
Slide7Can reproduce asexually
Regenerate when cut into pieces
Commonly reproduce by shedding fragments
Also reproduce sexuallyHermaphrodites
Reproduction
Slide8Section 28.2
Cnidarians
Slide9Phylum
Cnidaria
Jellyfish
Sea anemone
Hydras
Corals
Slide10Medusa
Umbrella-shaped
Polyp
TubelikeBoth have radial symmetry
Cells arranged into tissues
2 Body Forms
Slide11Characteristic specific to Cnidarians
Stinging cells found on tentacles
Nematocyst
Barbed harpoon within cnidocytesSome contain deadly toxins
Cnidocytes
Slide12Most primitive cnidarians
Life cycle contains polyp and medusa stages
Some found in freshwater
HydraUse basal disk to attach to objects
Marine HydrozoansMore complex than freshwater formsForm colonies
Reproduction
Sexual and asexual reproduction
Some species are hermaphrodites
Hydrozoans
Slide13True jellyfish
Range in size from a few cm to several feet in diameter
Medusas
Reproduce sexually
Scyphozoans
Slide14Anthozoans
Largest class of cnidarians
Polyps
Brightly colored sea anemones and corals
Tubelike body topped with tentacles
Reproduce sexually and asexually
Sea Anemones
Feed on fish that swim near their tentacles
Reproduce asexually by pulling self in half
Corals
Found in colonies
Stonelike
outer skeleton of calcium carbonate
Only outer layer of coral is alive
Slide15Section 28.3
Flatworms and Roundworms
Slide16Largest group of acoelomate worms
Tissues organized into organs
Bilateral symmetry
Belong to phylum PlatyhelminthesTurbellariaCestodaTrematoda
Flatworms
Slide17Most are marine flatworms
Freshwater flatworms
Planaria
Have ability to be cut in half and regenerate
Reproduction method
Turbellaria
Slide18Parasitic tapeworms
Attach themselves to the intestinal wall of host
Proglottids
String of rectangular body sectionsMay reach 40 ft. longCommonly infect humans when they eat infected meat that is undercooked.
Cestoda
Slide19Largest flatworm class
Parasitic worms called flukes
Endoparasites
contain tegument preventing them from being digested by hostSuck body fluids from host using pharynxLake itchBurrows under skin
Trematoda
Slide20Common canine parasites
Members of phylum
Nematoda
PseudocoelomLong, cylindrical bodies
Roundworms
Slide21Trichinella
spiralis
common roundworm that infects humansCauses trichinosisCommonly occurs due to eating undercooked pork
Roundworm Infection