Sponges and Cnidarians

Life Science

Review the Animal Kingdom

• 4 Major Characteristics?

• Multicellular

• Eukaryotic

• Heterotrophs

• Cells lack cell walls

7 Essential Functions?

• Feeding

• Respiration

• Circulation

• Excretion

• Response

• Movement

• Reproduction

Brain Encased Skull

jawsBony Skeleton

Lungs

Amniotic Egg

Hard Shells

Fur & Milk Glands

Phylum Porifera

“Pore-Bearers”

Sponges are the simplest of all animals.

They are multicellular, heterotrophic, have no cell walls, and have specialized cells.

Carnivorous- eat small crustaceans

Sheet sponge

Adult sponges are sessile.

They live attached to a single spot.

CAN”T MOVE

Sponges are asymmetrical filter feeders

Feed on : bacteria, unicellular algae, and protists through filter feeding.

IV. Phylum- Porifera (“pore bear”) –sponges – simplest of all animals

A. Body Plan – asymmetrical, pores all over body with large hole on top called osculum where water is pumped through, Have no mouth or gut, Have no tissues or organ systems, Simple functions are carried out by a few specialized cells

B. Protection: skeleton of spicules (glass-like material) or spongin (soft)

Asymmetrical?

Have no front or back ends, no left and right sides

– A large, cylindrical water pump

– The body forms a wall around a large central cavity through which water flows continually

Protection- Silica (cells of glass offer protection and support

C. Feeding – filter feeders, trap microorganisms in water flow.

1. Collar cells - specialized cells that use flagella to move a steady current of water thru the sponge. Each collar cell digests its own food.

2. Archaeocytes - specialized cells that make spicules

3. Pore cells – Cells thru which water flows into the body of a sponge

Major Body Functions

D. Respiration/ Circulation/ Excretion – water flow carries out all body functions (osmosis and diffusion)

• As water moves through the cavity:

1. Oxygen dissolved in the water diffuses into the surrounding cells

2. Carbon dioxide and other wastes, diffuse into the water and are carried away

Major Body Functions

E. Response/Movement- no nervous system, do produce toxins, adults don’t move (sessile), larva swim

F. Reproduction- sexually with internal fertilization between two different sponges or asexually by budding or fragmentation

Osculum

A large hole at the top of the sponge, through which water exits

The movement of water provides a simple mechanism for feeding, respiration, circulation and excretion

Water flow

Collar Cell

Spicule

Pore cell

Pore

Epidermal cell

Archaeocyte

Osculum

Central cavity

Pores

The Anatomy of a Sponge

Ecology of Sponges

1. Ideal habitats for marine animals such as snails, sea stars, sea cucumbers, and shrimp

2.Mutually beneficial relationships with bacteria, algae and plant-like protists

Adult sponge releases sperm into the water

Sperm fertilize eggs inside the body of another sponge

The zygote develops into a free swimming larva

Sperm (N)

Egg (N)

Larva (2N)

Mature sponge (2N)

Larva attaches to a hard surface

New sponge

Haploid (N)

Diploid (2N)

FERTILIZATION

MEIOSIS

Sponge Life Cycle (Sexual Reproduction)Sponges are hermaphrodites.

Review Questions

Answer the 4 questions on your own.

Asexual Reproduction-Budding

A new polyp genetically identical to the parent is formed.

Jelly fish

Lion’s Mane Jelly

Box Jelly

Some have eyes!

Colony of polyps

Deadly within 3 minutes!

Chironex fleckeri

Found off the coast of Australia

Over 100 deaths in the last 25 years

Anemones

Colonial Anemone

Coral Reefs

Brain Coral

Orange Cup Coral

Red Sea Fan

Sea Pen

Feathery Hydroid

Fungiid Coral- this coral can move!

Carpet Anemone

Mushroom Coral

Giant Sea Fan

Solid Table Coral

Staghorn Coral

Phylum Cnidaria –more complex than sponges

A. Carnivorous animals with stinging tentacles around their mouths

B. Simplest animals to exhibit symmetry – cnidarians have radial symmetry

C. Simplest animals to have true tissues including nerves

Examples: hydra, coral, sea anemone

Examples: jellyfish, portuguese man of war

Cnidarians have two body forms

Polyp - stationary, vase-shaped

Medusa - swimming, cup-shaped

Examples: hydras, jellyfishes, sea anemones, and corals

A. Hydrozoans: Most of life as polyp ex. hydra

B. Scyphozoans: Most of life as medusa ex. jellyfish

C. Anthozoans: Only polyp stage in the life cycle ex. corals and sea anemones

Simplest animal with true tissues.– soft bodied, have tentacles, radial symmetry,

1. Gut – gastrovascular cavity with one opening

2. Nerve net- detects stimuli

3. Hydrostatic Skeleton- movement and support with the use of muscles

 The Polyp and Medusa Stages

1. Polyp - Stationary, Examples: Hydra, Coral, and Sea Anemone

2. Medusa- Swimming, Cup Shaped. Examples: Jelly Fish and Man O War

Epidermis

Mesoglea

Gastroderm

Bell

gut

Mouth/anus

Tentacles

Tentacles

Mouth/anus

Gut

Polyp

Medusa

 The Polyp and Medusa Stages

3 tissue layers

1. Feeding- kill small prey with stinging cells in tentacles, digest in gut, food in and waste out of one opening.

2. Respiration/Circulation/Excretion- all by diffusion (no true organs)

3. Response- have specialized sensory cells and nerve net to gather info and react to stimuli.

Response

a. Statocysts: groups of sensory cells that help determine the direction of gravity

b. Ocelli: eyespots made of cells that detect light

(Stinging Cell)

(StingingStructure)

4. Movement- propel themselves with water using hydrostatic skeleton

5. Reproduction- asexually by budding, sexually by external fertilization, sperm and egg are released and meet in water

IX. Ecology of Cnidarians

A. Source of new drugs/chemicals sunscreen 855

B. Provide habitats for marine organisms

C. Source of food for other organisms (like sea turtles)

D. Symbiotic relationships with other organisms

Fertilization occurs in the open water, producing many diploid zygotes.

Sperm (N)

Egg (N)

Haploid

Diploid

FERTILIZATION

MEIOSIS

Male medusa(2N)

Zygote (2N)

Polyp

Buddingpolyp

Youngmedusa

Female medusa(2N)

Each zygote grows into a ciliated larva. The larva eventually attaches to a hard surface and develops into a polyp.

Swimming larva

The polypbuds to release young medusas.

Adult medusas reproduce sexually by releasing gametes intothe water.

Jellyfish Life Cycle (Sexual Reproduction)

Answer the 2 review questions