Rupp Bio II

Invertebrates No backbone No shared characteristics 12 phyla One million species 97% of all animals

Porifera Background Sponges No gastrula stage No true tissues or organs Approx. 10,000 species, only 150 are freshwater Sessile 1cm long to 2m in diameter

Porifera Body Plan Two layers Closed at bottom, open at top, and hollow Collar cells, pores, osculum

Porifera Body Plan Continued

Three Types of Sponges Those made with spongin, which is a support fiber Those made with spicules, which are hard particles of calcium carbonate and silicon dioxide Combination of spongin and spicules

Feeding Filter feeders Food sources Bacteria Protozoans Algae Organic matter Collar cells to amoebocytes to water to osculum

Reproduction—asexual Budding Gemmulation Offspring forms as an outgrowth of the parent If the bud does not separate a colony will form A cyst-like reproductive unit formed in freshwater sponges Formed in summer or fall and can overwinter Like a seed or spore

Reproduction—asexual con’t.

Regeneration— restoration or new growth of tissue that may have been injured or lost

Reproduction—sexual Sperm are pulled in by the collar cells Collar cells give the sperm to the amoebocytes Amoebocytes deliver sperm to the eggs Fertilization Larva form Larva are releases into the environment through the osculum Larva will develop into adults after cellular reorganization—metamorphosis

Reproduction—sexual con’t. Some sponges are hermaphrodites Self-fertilization is rare Cross-fertilization is productive for genetic variety All can produce eggs, therefore greater offspring numbers Some species maintain gender

Cnidarians and Ctenophores Radially symmetrical invertebrates Have tissues and a few simple organs Aquatic and most are marine

Cnidarians and Ctenophores— structure and function Two shapes Vase or polyp which is sessile Bell or medusa which is mobile Two layer construction Epidermis Gastrodermis Mesoglea—jelly-like layer between epidermis and gastrodermis Gastrovascular cavity Tentacles around mouth

Hydra Which type of body structure does this organism exhibit?

Jellyfish Which type of body structure does this organism exhibit?

Nay Nay’s Handywork National Zoo, Washington D. C.

Coral Which type of body structure does this organism exhibit?

Cnidarian and Ctenophore— feeding and defense Cnidocytes—specialized defense and prey capture cells Nematocysts—stinging cell within the cnidocyte Located on tentacles Trigger present When triggered a filament extends to deliver the sting, poison, or wrap the intruder Prey captured, moved into mouth, nutrients absorbed, prey expelled through mouth

Cnidarians and Ctenophores— nervous system Nerve net Stimulus-response action—no thinking Entire body contracts Feeding and swimming are coordinated by the nerve net Stimulus to nerve net to epidermis to contraction

Cnidarian classification Three classes Hydrozoans Only polyps Only medusas Alternate generations Mixed colonies Scyphozoans Medusa Anthozoans Polyps

Hydrozoans 3700 species Typically marine and colonial Obelia Polyps on stalks Some feed, others reproduce Physalia Portuguese man-of-war Colony of medusas and polyps Gas-filled float Polyps Feeding and digestions Reproduction Huge numbers of cnidocytes

Hydrozoans—Hydra Very unique Only polyps Freshwater Not colonial Can be green due to symbiotic relationship with algae Capable of movement Gas bubble float Somersaulting Asexual reproduction— budding in warm weather Sexual reproduction— cool fall weather triggers gamete formation Hermaphroditic Male Female

Scyphozoans Name means “cup animals” Dominant form is the medusa Jellyfish 2cm to 4 m in size Aurelia Alternation of generations

Anthozoans Name means “flower animals” 6100 marine species Anemones and corals Anemones Polyps Feed on fish Symbiotic relationship with clown fish Corals Small colonial polyps Connect to each other with CaCO3 skeletons Form reefs Tropical dwelling Symbiotic with algae for extraction of calcium from sea water, therefore shallow living

Anthozoans Anemones Corals

Ctenophores Approximately 100 species Marine dwelling Comb-like rows of cilia Often called comb jellies Cilia are used for movement as opposed to contractile swimming— largest organisms to move this way Colloblasts instead of cnidocytes Secrete a sticky substance Binds prey Located on two tentacles Apical organ at one end of body allows a sense of orientation in water— nerves in apical organ coordinate cilia Bioluminescent