Parazoa and RadiataSponges
CnidariansCtenophores
Phylum Porifera: The Sponges
General InformationMainly marine organisms;
evolved from choanoflagellates
May have algae or bacteria that give them color
Larva are flagellated, adults considered sessile
Many disease-fighting compounds
holdfast
Tube Sponges
Encrusting Sponges
CharacteristicsCan reproduce sexually
or asexually
Gas exchange and excretion - diffusion at individual cells
Supported by skeletal fibers:
spicules or spongin
Simple animals made of few specialized cells; NO tissues
Asymmetrical
Body with ostia
Most are filter feeders / suspension feeders 1 family is
carnivorous
Anatomy of a Sponge:
OsculumSpongocoelChoanocyteAmoebocyteMesohyl
Suspension Feeding & Gas Exchange
Sponge Reproduction:Asexual reproduction
Buds or gemmules
Sexually – most sponges are hermaphroditesCells become egg/spermSperm released into waterFertilization occurs in mesohyl
(egg)Zygote becomes flagellated larva
that leaves in flow of water
Phylum CnidariaJellyfish
Box jelly
Coral
Sea anemone
Main CharacteristicsDiploblastic, radial symmetry
Cnidocytes with nematocysts concentrated in tentacles
Gastrovascular cavity with 1 opening2 layers separated by mesoglea
Gas exchange and excretion occur by diffusion
Structure cont…Nerve nets
Connect sensory cells to contractile cellsSense organs around edge of bodyEx. photoreceptors
Contractile cells Not true musclesAct as hydrostatic skeleton
Cnidarians come in 2 forms:Medusa – tentacles
downPolyp – tentacles
up
Many alternate between medusa and polyp during life cycle
4 Classes of Cnidaria
Hydrozoa Scyphozoa Cuboza Anthozoa
Cnidarians are CarnivoresFeed on fish, larva, comb jellies, other
zooplankton
Sting prey with their tentacles
Mouth gastrovascular cavity mouth
Jellyfish.asf
A word about corals:Many have symbiotic zooxanthellae
Environmental issue: Coral Bleaching
Interesting Facts…Portuguese Man-
of-WarColonial
Has sail-like float
Tentacles can grow up to 165 feet and are nearly invisible
More interesting facts…Box Jellies
More toxic than Man-of-War
Stings can lead to heart failure within minutes
Tentacles may reach 15 feet
CTENOPHORA: THE COMB JELLIESDiploblastic??; Biradial
Symmetry
Swim with 8 rows of ciliary combs
Have 2 long tentacles with sticky cellsColloblasts
Eat large amounts of fish larva & planktonMouth + 2 anal pores
Introduced/Invasive species (Black Sea)