Biology 1

Chapter 29

Sponges and Cnidarians

Invertebrates = Animals _____________ a backbone

1. make up about 97% of all animals

2. identified by their shape or _______________ = general form

3. body parts arranged around a central point

Types of Symmetry:

1. Asymmetrical -- _____definite form; (ex. ameba, sponge)

2. Spherical -- ___________ shape; roll around in water; (ex. volox, radiolarians)

3. Radial -- ____________ in shape with different ends; move very little; (ex. Hydra,

Anemone)

4. Bilateral -- 2-sided shape with ____________ sides being mirror images of each

other; (ex. Piranha, Humans, Butterfly)

Special Names for Body Areas:

A) Anterior -- ______ end E) Distal – farther away from

B) Posterior -- _____ end F) Proximal – closer to

C) Dorsal -- _______ surface G) Lateral -- side

D) Ventral -- ______ surface H) Medial -- middle

Cephaliztion -- ____________________ are located at the anterior end.

3 Germ Layers:

Germ Layer -- a layer of developing cells that give rise to specific structures

1. Ectoderm -- outside embryonic germ layer that forms the animal's covering.

(______________________________________)

2. Endoderm -- inner germ layer that forms the lining of the gut.

(____________________________________)

3. Mesoderm -- middle layer that forms muscles and other body organs.

(____________________________________)

I. KINGDOM ANIMALIA

A. PHYLUM PORIFERA "__________ Bearer" -- (Sponges)

Characteristics of Sponges

1. ___________body, penetrated with _____________. (extremely porous)

2. Primitive skeleton made of:

a. Spicules = filaments formed from __________or ________________

b. Spongin = a network of _______________fibers

3. Body has 2 cell layers separated by the Mesenchyme = ________________.

4. Habitat = mostly _______________as single individuals or colonial groups.

5. Sessile = __________________attached to object. (Does not move)

6. Color varies -- white, red, purple, black.

7. Size ranges -- 1cm to 2m.

8. Structures:

A. Incurrent Pores = small opening where water ____________sponge.

B. Osculum = large opening where water ___________sponge; (controls water flow).

C. Collar Cells or Choanocytes = (endoderm layer) cells that contain _______________that set up currents to draw water into sponge

D. Amebocytes = cells that move through mesenchyme and carry food and oxygen to cells, picking up wastes and taking sperm to eggs.

Feeding of sponges

1. _____________diatoms, protozoa, bacteria and organic material from water.

2. Food is engulfed and digested by enzymes in collar cells.

3. Food is distributed to cells by amebocytes

4. Undigested material is carried to collar cells by amebocytes for excretion

Respiration

1. Gases are exchanged through the ______________of its cell membranes.

(________________through the membranes)

Reproduction

1. Asexual:

a. Budding - ___________special buds that are formed on the sponge’s

surface in unfavorable conditions, become

surrounded by a heavy coat, filled with amebocytes

and food.

b. Regeneration - ability to grow new parts when cut up into_______. (Done

commercially and sold for bathing).

2. Sexual:

Hermaphroditism = eggs and sperm are produced in ________individual

(sperm is released from one sponge and picked up by

another. The sperm are carried to the eggs by

amebocytes. The zygote forms into a larva which

leaves sponge and forms a new sponge.)

B. PHYLUM CNIDARIA/COELENTERATA

(Includes jellyfish, sea anemone, coral, and hydra)

Characteristics of Cnidarians

1. ________________body with 2 cell layers.

2. Gastrovascular cavity - "Coelenterow" has _______ opening

3. Cnidocytes = __________ cells at end of __________ which help capture prey.

4. Habitat - marine and some freshwater.

5. Contains Mesoglea = _______________middle layer.

6. 2 Body forms:

a. Polyp - sessile; __________-like

b. Medusa - free-swimming, ____________shaped

3 Classes of Cnidarians

1. Class Hydrozoa

(Ex. Hydra, Obelia, Physalia)

Hydra: Characteristics

1. Habitat - freshwater ponds, lakes, streams

2. Polyp Stage only - 1.4 cm in size

3. ______________- cells used for attachment are found at posterior end.

4. Hermaphroditic –(contains both male and female reproductive parts)

reproduces _________ sexually and asexually

5. Sessile

Feeding of Hydra:

1. Feeds on protozoa and Daphnia

(captures with Nematocysts = coiled harpoon like ________in cnidocytes on the____________.)

2. Tentacles contract and push prey through mouth into gastrovascular cavity.

2. Class Scyphozoa -- (_________animals)

(ex. jelly fish = Aurelia)

Characteristics of jelly fish

1. _________________________________preferred

2. free swimming

3. Class Anthozoa -- (____________animals)

(ex. sea anemone, coral)

Characteristics of flower animals

1. ________________

2. sessile as adults

3. _______________are free swimmers

Coral Reefs

3 kinds - found only in warm water, shallow & clear water

1. _____________reef -- close to beach

2. _____________reef -- farther out

3. _____________ reef -- found on underwater mountains and volcano tops (make

lagoons)

Ø Portuguese man-of-war (class scyphozoa) -- has the most powerful natural neurotoxin in the world.