Exam 4

Porifera

-no true tissue

-sessile

-suspension feeders (filter eaters)

-choanocytes

-amoebocytes

-skeletal specuiles

-hermaphoriditic cross fertilization

-regeneration and gemmules

sessile

-To be attached to an organism but are not parasitic and cannot move.

-Cnidarian polyps

-barnacles

-mussels

-sea Lillies (Crinoidea)

-barchiopods

choanocytes (collar cells)

Specialized cells in spongocoel.

-flagellated: Flagella beats water through pores and pushes out through osculum.

-Feeding: H2O passes and is trapped in mucus coating.

-Digest: via phagocytosis. Transfered via amoebocytes

-Gametes: can turn into either egg or sperm when needed.

Amoebocytes

pseudopod-bearing cells found in the mesohyl.

-highly versatile and perform several vital roles

-In sponge, they help with regeneration

Hermaphrodites (monoecious)

possession of both male and female organs.

-no self-fertilization

-eggs and sperm are produced in mesohyl

-sperm released through osculum

-sperm penetrate pores of following sponge with mesohyl and fertilization happens

Gemmules

-freshy water sponges have these

-asexual buds specialized in surviving freezing lakes

-Gemmules once it is warmer, go through mitosis and produce new sponge

Cnidaria Clade

-Radial symmetry

-Diploblastic

-Gastrovascular Cavity

-Cnidocytes (stinging cells)

-Nerve nets

-Polyp & Medusa

-medusozoa

-anthozoa

Diploblastic

2 germ layers: endoderm and ectoderm

Gastrovascular Cavity (Incomplete digestive system)

-Cavity has a single opening that functions as both mouth and anus.

-food is captures and pushed into digestive chamber. Those nutrients and absorbed

-any remaining matter is excreted by the same opening

Polyp form

cylindrical forms that adhere to substrate by aboral end of body stalk.

-mouth and tentacles face upward to catch prey.

-sessile

Medusae form

flattened and bell-shaped. “inside out”

-mouth and tentacles face downward

-motile and typically planktonic

(subclade) Medusozoa

medusa (jelly fish) production

-Hydrozoans

-Scyphozoans

-Cubozoa (box jellies)

Hydrozoans

Alteration generations between Polyp (Dom stage) & Medusa

H: Obelia & Physalia

colonial and produce tiny medusae through asexually budding.

-medusae reproduce sexually to produce planula larva which forms into new polyp colony

H: Hydra

ONLY exists as polyp form

-freshwater

Scyphozoans “True jellyfish”

medusa is dom and prominent.

1. polyp (scyphistoma) goes through transverse fission (strobilation).

2. Polyp elongates and buds off star-shaped medusae (ephyra)

-Coastal: Aurelia

-Open ocean (pelagic): no polyp due to lack of substrate. no scyphistoma

S: Aurelia “moon jellies”

1. pass through small, specialized polyp stage (Scyphistoma).

2. Scyphistoma matures and becomes strobila

3. strobila goes through strobilation and then transforms into ephyra

Cubozoa “Box Jellies”

bell-shaped bodies with squared off edges.

-LETHAL: Chrionex fleckeri

-tentacles that stretch up to 2 meters with cnidocytes

C: Chrionex fleckeri “sea wasp”

supa deadly

-found in Great Barrier Reef of Australia

Anthozoa (subclade)

Polyp ONLY

sessile

-Sea anemones

-Corals

A: Corals

extract CaCo3 from sea H2O to form calcareous external skeleton.

-colonial reefs but very diverse. Solitary, colonial, and soft. No reefs, yes reefs.

A: Sea Anemones

Hydrostatic skeleton with a central gastrovascular cavity with H2O. Provide structure for contractile fibers to work against.

-tentacles to capture prey and push to gastrovascular cavity

-tentacles w/ cnidocytes. They have nematocysts (capsule-like organelles for defense and prey capture).

-nerve nets

-360 sensory receptors (radial)

Nerve Net

ONLY in Cnidaria

decentralized nervous system. No brain.

-network of nerves aid in coordination

-super important for sessile beings

Ctenophora Clade

-”comb jellies/ sea walnuts”

-8 rows of cilia. Look like medusae but NOT.

-adhesive colloblasts in retractable tentacles

-bioluminescent

-complete digestive system

-cestum (venus’ girdle)

-calcerous particles in sensory organ

Lophotrochozoa

Some exhibit lophophore- ciliated tentacles for feeding.

• Ectoprocta, Brachiopoda, phoronids

Some exhibit trochophore larvae stage

• Mollusca and Annelida

Rest of sub clades:

Platyhelminthes, Lophophores

Ectoprocta/Bryozoans “mossy animals”

-colonial invertebrates with lophophores

-mostly marine BUT freshwater Pectinatella (Floridian found)

-reef builders with CaCO3 exoskeletons

Brachiopoda “lamp shells”

supa old (Paleozoic & mesozoic era) filter feeders. They attach to sea floor with pedicle (muscular stalk)

-Marine and deep H2O

-Dorsal and Ventral shells

Platyhelminthes “flat worms”

-Bilateral symmetry

-Acoelomate, triploblastic with true muscles, tissues, and organs.

-gastrovascular cavity (incomplete system)

2 Lineages:

1. Catenulida “chain worms”: mostly freshwater

2. Rhabditophora: free living Planeria: Girardia, parasitic: Trematodes ”Flukes”, Monogeneans, Cestodes “tapeworms”

R: Brown Planeria “Girardia tigrina”

• carnivorous and feed on carrion

• moderate cephalization: Cerebral ganglia & ventral nerve cords

• Sensory organs: photoreceptor ocelli and olfactory auricles

• Osmoregulate via protonephridia (flame cells). Remove ammonia through diffusion.

• ciliated

• reproduce asexually via transverse fission

• most are moneocious(hermaphroditic) but cross-fertilize

R: Trematoda

Schistosoma spp “blood fluke” | fasciola hepatica “sheep liver fluke” | Chlonorchis sinensis “human liver fluke”

-Digenetic Fluke: 2 or more hosts

-suckers for attachment

-alteration of generations: Asexual development in intermediate host (ie. snail/invertebrates). Sexual in definitive host.

R: Monogeneans

Gyrodactylus sp | Polystama sp

-Monogenetic Fluke: 1 host

-ectoparasites of fish

-hermaphroditic/monecious and reproduce sexually

Opisthaptor- small hooks for attachment

R: Cestoda “Tapeworms”

Taenia pisiformis

-no digestive system

-scolex: attachment organ

-Hermaphoridites