Chapter 33 Porifera (Sponges), Cnidarians (hydra, jellyfish, sea anemone, some corals) Ctenophores (...

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Chapter 33 Porifera (Sponges), Cnidarians (hydra, jellyfish, sea anemone, some corals) Ctenophores ( comb jellies) om: http://www.bio.miami.edu/dana/160/160S06_14.html & http://sps.k12.ar.us/massengale/images/brac-sp

Transcript of Chapter 33 Porifera (Sponges), Cnidarians (hydra, jellyfish, sea anemone, some corals) Ctenophores (...

Chapter 33

Porifera (Sponges),

Cnidarians (hydra, jellyfish, sea anemone, some corals)

Ctenophores ( comb jellies) pictures from: http://www.bio.miami.edu/dana/160/160S06_14.html & http://sps.k12.ar.us/massengale/images/brac-sponges-21.jpg

Animalia: A Progression of Complexity• As we begin discussing the animal kingdom-Consider

that as animal phyla diverge, organs and organ systems are added, increasing complexity.– Tissues ( # germ layers) – Body symmetry – Internal body cavity – Organs and Organ systems:

• integumentary system - protection (injury, infection, water loss) • digestive system - food processing • nervous system - coordination; response to environment• reproductive system – asexual or sexual, external or internal• excretory system - removal nitrogenous waste from body fluid • skeletal system - structural support • circulatory system - internal distribution of materials • respiratory system - gas exchange (O2 in, CO2 our)

Noted from: http://www.bio.miami.edu/dana/160/160S06_14.html

I. Porifera

• Invertebrate (no backbone)

• Asymmetrical

• No true tissues or organs

• No gastrula stage (embryonic development)

• Less cell specialization than other animals

• All species -Aquatic

• Adult is Sessile (attach to surface, do not move)

http://sps.k12.ar.us/massengale/images/brac-sponges-21.jpg

Why are sponges considered animals?

• Early biologists thought they were plants.• BUT- Have 2 key characteristics of animals:

–Heterotrophic–Multicellular– (Reproduction is asexual or sexual)– (Mobility- adults are sessile- but some species can

move up to 4mm/day (http://www.ucmp.berkeley.edu/porifera/poriferalh.html) *larvae have flagella.)

• Represent transition from unicellular to multicellular life.

A. Basic Body plan of a Sponge

1. Asymmetrical2. Sessile3. Vocabulary of sponge parts:• Hollow cylinder shape, closed at bottom, opening

at top called Osculum.• Interior lined with Choanocytes – flagellated

cells that draw water into the sponge through pores in the body wall called Ostia.

• 2 layers of cells separated by mesohyl (a jelly like substance)

Sponge Skeleton

2 types support- (different sponges use one or both):

• Spongin - tough, flexible protein fibers

or

• Spicules – hard calcium carbonate (like in limestone, teeth & bones) or hard silicon dioxide (quartz, glass)

Picture from: http://www-biol.paisley.ac.uk/biomedia/graphics/jpegs/SPICULES.gif

http://io.uwinnipeg.ca/~simmons/Chap3298/img013.jpg

B. Digestive System/Wastes

1. Filter Feeding- bits of organic matter or bacteria

2. Amoebocytes- crawling cells that deliver nutrients from choanocytes to the rest of the body

3. Digestion is Intracellular -wastes & CO2 expelled with water as it passes through osculum

C. Reproductive System1. Asexual

a. Budding- part of the parent pinches off & forms a new organism

b. Gemmules – a reproductive structure in sponges, -produced in harsh conditions-a food-filled ball of amoebocytes in a protective coat

c. Regeneration- regrowth of missing cells.

2. Sexuala. Sperm are released into water, enters next sponge through pores, choanocytes engulf sperm. Carry to ameobocytes, carry them to egg in mesophyl. Produces a flagellated Larvae (immature form)

b. Hermaphrodite- each sponge has both eggs & sperm

II. Cnidaria (Hydra, Jellyfish, Sea Anemones, some corals)

A. Body Plan1. Stages:

Medusa –bell shaped, swims

Polyp – vase-shaped, sessile2. 2 cell tissue layers-

Epidermis outside layer

Gastrodermis inside layer

-with Mesoglea in between)3. Gastrovascular cavity (gut)4. Tentacles

http://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/cnidariaDiagram.jpeg

POLYP

MEDUSA

B. Digestive System/Waste1.Cnidocytes (special defensive cell) have

Nematocysts (coiled organelle with stinging filament)

2. Tentacles push prey through mouth & into gastrointestinal cavity 3. Digestion is

Extracellular, wastes

expelled through mouth.

http://www.emc.maricopa.edu/faculty/farabee/biobk/cnidaria_1.gif

C. Nervous System

1. Nerve Net -Nerve cells located below epidermis near the mesoglea interconnect and form a nerve net throughout the body.

Cnidarians have both muscle fibers and nerve fibers, making these animals capable of directional movement.

2. Movement – using pulsing tentacles

D. Classes1. Hydrozoa ( 3,700 species) ex- Obelia, Portuguese

Man-O War.2. Cubozoa ex- box jellies, sea wasp3. Scyphozoa “cup-animals” jellyfish4. Anthozoa (6,100 species) “flower animals” like sea

anemones, coralsQUESTIONS:• Use your book to describe one organism from each

of the 4 classes.• List & diagram the steps in describing the cnidarian

hunting & feeding process (use terms for special parts.)

E. Reproductive Systems-

• Some reproduce asexually (see Hydra-budding) especially in warmer temperatures.

• Sexual reproduction- – lower temps– hermaphrodites. – Motile sperm, egg in ovary.

III. Ctenophora (100 species)

Ctenophora means “comb holder”- named for the 8 comb-like rows of cilia that run along outside of these animals

How are they different than jellyfish?

A. Movement - beating cilia

               

                          

http://www.ucmp.berkeley.edu/cnidaria/ctenophora.html

B. Digestive

-ctenophores are voracious predators. -Unlike cnidarians, they lack stinging cells.

(no cnidocytes)

-Instead,to capture prey, have sticky cells

called colloblasts. located on ends of 2 tentacles.

-In a few species, special cilia in the mouth are used for biting gelatinous prey.

C. Nervous- have an apical organ for sensing environment.

D. Bioluminescence –glow with light they produce with chemicals