lab 10 porifera & cnidaria

7/30/2019 Lab 10 Porifera & Cnidaria

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Phylum Porifera

&

Phylum Cnidaria

Kingdom Animalia


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AnimaliaAnimals are multicellular and heterotrophic. They are arranged in taxa based on their

morphology (form and appearance).

They can be Parazoa (cellular structure) orEumetazoa (true tissue structure).

All possess Bilateral symmetry (a body planin which both sides around the central axismirror each other)orRadial symmetry (abody plan in which there is a central disc withother body parts radiating from the center).


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Figure 33.2

ANCESTRALPROTIST

Commonancestor ofall animals

Porifera

Cnidaria

Lophotrochozoa

Ecdysozoa

Deuterostomia

Eumetazoa B

ilateri

a


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Phylum Porifera

Consists mainly of sponges.

Parazoans. Derives its name based on the porous body of its

members.

Possess 1-3 body forms: Asconoid, Syconoid and

Leuconoid The body form is based on the folding of the body

wall with the Asconoid form being the least folded.

The body wall of sponges is made

of sharp skeletal structures called spicules.

Asconoid LeuconoidSyconoid


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Phylum: Porifera

are classified into 3 Classes: Calcarea contains sponges with spicules made of

calcium carbonate and Asconoid, Syconoid and

Leuconoid body forms.

Hexactinellida contains sponges with spiculesmade of silica and a Syconoid body form.

Demospongiae are sponges with spicules made of

calcium and spongin (collagen) and which possess

a Leuconoid body form.


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Class Calcarea

Grantia

A. Radial Canal (opens to inside), lined with

choanocytes

B. Incurrent Canal (opens to outside)

C. Ostium (opening to an incurrent cannal)

Grantia (cross section x.s.)

A. Osculum

B. Spongocoel

Grantia (l.s.)

Class Calcarea

Spicules


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Class Calcarea

Leucosolenia sp.


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Class Hexactinellida

Spicules made of silica


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Class Demospongia


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Phylum Cnidaria

Includes jellyfish, hydras, sea anemones andcoral animals.

Acoelomate

Diploblastic, eumetazoans with radialsymmetry.

Possess an oral (mouth/anus) and aboral

(base) axis.

Have two body forms:

- Polyp

- Medusa


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Cnidarians have 2 body forms, the sessile polyp

(Hydra) and the medusa (Aurelia).


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Phylum Cnidaria Some cnidarians exhibit both body forms

(Metagenesis) in their life cycle (Obelia).

The polyp body form is cylindrical with tentaclesextending up around the oral axis.

The medusa body form is shaped like an umbrellawith tentacles extending down around the oral axis.Tentacles are used to capture prey. Tentacles have stinging cells called cniodcyst. The

cnidocysts actually have capsules called cnidae or

nematocysts that extend and sting prey when thecnidocysts are stimulated.


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Cnidarian Body Forms

1. Polyp only SeaAnemone


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2. Medusa only JellyFish


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3. Both Polyp and

Medusa


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Life cycle ofObelia


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Classes of Cnidaria

Cnidarians are classified into three classes:

1.Hydrozoa2. Scyphozoa

3. Anthozoa


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Class Hydrozoa

Most are metagenic and colonial; Obelia andPhysalia. A notable, freshwater exception is

Hydra which is solitary and basically only a polyp.

Hydra

Budding

Hydra


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Class Hydrozoa

Hydra l.s.

A. Gastrovascular cavity

B. Gastrodermis

C. Epidermis

D. Mesoglea

Hydra c.s.

A. Gastrovascular

cavity

B. Gastrodermis

C. Epidermis

D. Mesoglea


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A.Hydranth (feeding polyp)

B.Gonangium (reproductive polyp)

C.Medusa bud within Gonangium

Class Hydrozoa

A

B

C


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Class Scyphozoa

Dominated by marine cnidarians with themedusa body form.

These are sometimes referred to as the True

Jellyfish (Aurelia is a typical example).


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Class Anthozoa Contains both solitary and colonial members in which

the medusa stage is completely absent.

This class includes the hard corals (brain andstaghorn), anemones, and soft corals (sea fans, seapansies and sea whips).


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Hard Corals

Brain Coral

Staghorn Coral


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Sea Anemones

Genus Metridium Anemone


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Soft Corals

Soft Corals

Sea Fan

Coral Reef

lab 10 porifera & cnidaria

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