Invertebrates: Sponges and Cnidarians

Journal 2

You are an expert taxonomist who has been You are an expert taxonomist who has been given an unknown specimen to identify. given an unknown specimen to identify. You suspect that it is an animal. How could You suspect that it is an animal. How could you prove your hypothesis?you prove your hypothesis?

Open your books to page 664Open your books to page 664

Sponges: Phylum Phylum PoriferaPorifera means- pore bearer means- pore bearer Simplest of all animalsSimplest of all animals AssymetricalAssymetrical animals that live in animals that live in

shallow watersshallow waters SessileSessile filter-feeders whose bodies filter-feeders whose bodies

have many poreshave many pores AcoelomatesAcoelomates-no body cavity-no body cavity Obtain oxygen by filtering waterObtain oxygen by filtering water Uses: cleaning, bathing, cosmeticsUses: cleaning, bathing, cosmetics No nervous system or organ systemsNo nervous system or organ systems

Sponge Reproduction Reproduce Asexually by Reproduce Asexually by

buddingbudding:: Buds form from sides of parent Buds form from sides of parent

sponge, bud break off and grow sponge, bud break off and grow into new individualinto new individual

can grow back missing parts can grow back missing parts (regeneration)(regeneration)

Reproduce sexually:Reproduce sexually: HermaphroditesHermaphrodites:: produce both produce both

eggs and spermeggs and sperm Gametes are released into waterGametes are released into water

Sponge Body Structures: OsculumOsculum: large opening : large opening

at the top of the spongeat the top of the sponge Pore cellsPore cells: openings to : openings to

bring in waterbring in water Collar cellsCollar cells

(choanocytes): line (choanocytes): line interior, have flagella to interior, have flagella to help filter waterhelp filter water

SpiculesSpicules: hard, : hard, supportive structures supportive structures found in body of spongefound in body of sponge

LABEL THE SPONGE ON YOUR LEFT PAGE!!!

Section 26-2

Water flow

Choanocyte

Spicule

Pore cell

Pore

Epidermal cell

Archaeocyte

Osculum

Central cavity

Pores

The Anatomy of a Sponge

Cnidarians:

Phylum Phylum CnidariaCnidaria: means : means “stinging cell”“stinging cell”

Marine Marine Radial symmetryRadial symmetry Have tentaclesHave tentacles Predators: capture and poison Predators: capture and poison

prey with stinging cells on prey with stinging cells on tentacles tentacles (NEMATOCYST)(NEMATOCYST)

AcoelomatesAcoelomates Oxygen diffuses into body from Oxygen diffuses into body from

waterwater

Cnidarian Body Forms PolypPolyp: body with : body with

tentacles hanging tentacles hanging upwardupward

Ex: hydra, sea Ex: hydra, sea anemoneanemone

MedusaMedusa: body with : body with tentacles hanging tentacles hanging downwarddownward

Ex: jellyfishEx: jellyfish

Cnidarian Reproduction: Asexually reproduce by Asexually reproduce by

buddingbudding Sexually reproduce in Sexually reproduce in

medusa form only, sperm medusa form only, sperm and eggs are released into and eggs are released into waterwater

Thousands of gametes are Thousands of gametes are released at a timereleased at a time

Time to Think!

Why do sponges and cnidarians release Why do sponges and cnidarians release so many gametes into the water?so many gametes into the water?

The body plan of an animal relates to its The body plan of an animal relates to its complexity. What does that tell you about complexity. What does that tell you about

sponges and Cnidarians since they are sponges and Cnidarians since they are both both acoelomatesacoelomates??

Basal discBasal disc: sticky end of polyp : sticky end of polyp form which allows them to stay in form which allows them to stay in one spotone spot

One body opening One body opening (mouth)(mouth) for food for food to enter and wastes to exitto enter and wastes to exit

Gastrovascular cavityGastrovascular cavity: interior : interior cavity where food is digested & cavity where food is digested & nutrients are circulated around the nutrients are circulated around the bodybody

Nerve netNerve net: net of nerves that allow : net of nerves that allow impulses to travel around the body, impulses to travel around the body, senses the environmentsenses the environment

MusclesMuscles: some muscles are present; : some muscles are present; allows for some movementallows for some movementLabel the hydra on

your left page

Cnidarian Structures:Cnidarian Structures:

Three groups of cnidarians HydrozoansHydrozoans: colonies which : colonies which

appear to be one organismappear to be one organism Ex: portugese-man-of-warEx: portugese-man-of-war ScyphorozoansScyphorozoans: independent : independent

medusasmedusas Ex: jellyfish, box jelliesEx: jellyfish, box jellies AnthozoansAnthozoans: colonies of polyps: colonies of polyps Ex: corals, sea anemonesEx: corals, sea anemones

Quiz 1.1. Sponges __ animals.Sponges __ animals.

a. are b. are nota. are b. are not

2.2. Sponges can reproduce asexually by ___.Sponges can reproduce asexually by ___.

a. budding b. regeneration c. both a. budding b. regeneration c. both

3.3. Hydras have their tentacles pointing upwards. They Hydras have their tentacles pointing upwards. They are __.are __.

a. medusas b. nematocysts c. polypsa. medusas b. nematocysts c. polyps

4.4. All cnidarians have ___ symmetry.All cnidarians have ___ symmetry.

a. bilateral b. radial c. no symmetrya. bilateral b. radial c. no symmetry

5.5. Cnidarians poison their prey with stinging cells called Cnidarians poison their prey with stinging cells called ___.___.

a. choanocytes b.nematocysts c. osculuma. choanocytes b.nematocysts c. osculum