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Chapter 33 Porifera (Sponges),

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1 Chapter 33 Porifera (Sponges),
Cnidarians (hydra, jellyfish, sea anemone, some corals) Ctenophores ( comb jellies) pictures from: &

2 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:

3 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)

4 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 ( *larvae have flagella.) Represent transition from unicellular to multicellular life.

5 A. Basic Body plan of a Sponge
Asymmetrical Sessile 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)

6 Sponge Skeleton Spongin - tough, flexible protein fibers
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:


8 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

9 C. Reproductive System 1. 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. Sexual a. 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

10 II. Cnidaria (Hydra, Jellyfish, Sea Anemones, some corals)
A. Body Plan 1. Stages: Medusa –bell shaped, swims Polyp – vase-shaped, sessile 2. 2 cell tissue layers- Epidermis outside layer Gastrodermis inside layer -with Mesoglea in between) 3. Gastrovascular cavity (gut) 4. Tentacles


12 B. Digestive System/Waste
Cnidocytes (special defensive cell) have Nematocysts (coiled organelle with stinging filament) Tentacles push prey through mouth & into gastrointestinal cavity Digestion is Extracellular, wastes expelled through mouth.

13 C. Nervous System 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

14 D. Classes 1. Hydrozoa ( 3,700 species) ex- Obelia, Portuguese Man-O War. 2. Cubozoa ex- box jellies, sea wasp 3. Scyphozoa “cup-animals” jellyfish Anthozoa (6,100 species) “flower animals” like sea anemones, corals QUESTIONS: 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.)

15 E. Reproductive Systems-
Some reproduce asexually (see Hydra-budding) especially in warmer temperatures. Sexual reproduction- lower temps hermaphrodites. Motile sperm, egg in ovary.

16 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                                          

17 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.

18 Nervous- have an apical organ for sensing environment.
D. Bioluminescence –glow with light they produce with chemicals

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