Phylum Porifera and Cnideria
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Transcript of Phylum Porifera and Cnideria
Phylum Porifera and Cnideria
From sponges to Men of War
Phylum Porifera – Fact Sheet ReviewSymmetry/Body Plan: assymetrical. No digestive organs, so no “body plan”.
Digestion:Structures: collar cells, amoeboid cells
and microvilliCollar cells cause water to filter through the
sponge.Microvilli absorb microscopic nutrients.Amoeboid cells complete digestion.
Fact Sheet Review cont’dExcretion: water is let out of the osculum.
Respiration: done at the cellular level. Amoeboid cells help to circulate gases (among other nutrients).
Nervous or control system: Non-existant.
Movement: sessile (does not move; non-motile)
Fact Sheet Review cont’dReproduction: both asexual and sexual.Asexual: regeneration of cells (if the sponge
is damaged); gemmule (spore) formation; budding.
Sexual: egg and sperm cells are produced by amoeboid cells; sperm leave one sponge and are filtered into another to cause fertilization.
Representative Organisms and NotesRepresentative organism: the sponge.Classified by type of spicule in skeleton:1. Chalk sponge – skeleton is made of CaCO3
2. Glass sponge – skeleton is made of silica3. No spicules (only use soft protein fibers
called spongin).
Phylum Cnideria – Fact Sheet ReviewSymmetry/Body Plan: radial symmetry. Sac body plan (mouth = anus).
Digestion:Structures: gastrovascular cavity,
gastrodermal cellsDigestion starts in gastrovascular cavity;
nutrients eventually enter gastrodermal cells and diffuse throughout the body.
Fact Sheet Review cont’dExcretion: wastes will leave through the mouth (anus).
Respiration: done at the cellular level. Gases distributed by the gastrovascular cavity.
Nervous or control system: Simple nerve net.
Movement: motile in medusa stage. Sessile in polyp stage. Movement aided by muscle cells.
Fact Sheet Review cont’dReproduction: both asexual and sexual.Asexual: regeneration of cells (if a small
piece of the cnidarian breaks off); budding.
Sexual: egg and sperm cells are produced during the medusa stage (usually). These combine into a zygote.
Representative Organisms and NotesRepresentative organisms: jellyfish, corals, anemones, and Portugese man-of-war.Vary in how they cycle between medusa and
polyp stages.Jellyfish = mostly medusa; short polyp stage.Corals = colonial polyps (no medusa).Anemones = solitary polyps (no medusa).Portugese man-of-war = some polyps (for
feeding and floating), some medusae (for reproduction).
Representative Organisms
Notes cont’dDefenses:Cnidarians produce cnidocytes
Contain a capsule (nematocyst) that, when “tripped”, shoots out.
Traps or poisons prey.
The bitter sting…