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)
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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)
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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

11. POLYP
MEDUSA

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