SPONGES

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SPONGES

• PHYLUM PORIFERA

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• Major Characteristics of
• the Phylum Porifera
• Sponges are
• asymmetrical
• multicellular
• sessile
• Heterotrophic
• eukaryotic
• No body cavity
• evolved from Kingdom Protista
• No systems (digestive, excretory, circulatory,
  or respiratory)

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Water flowing through sponges provides food and
oxygen, as well as a means for waste removal.
Green dye was placed next to a sponge-- note the
flow from the osculum! Small incurrent pores
allow water in.
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Sponges
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Cell types (3 types) 1. Choanocyte cells
(a.k.a. collar cells) have nets and
flagella. They surround pores, bring water in,
and filter food particles.
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Cell types (2nd type)
2. Epithelial cellsoften brightly colored.
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Cell types (3rd type)

• Amoebocyte cells have many jobs
• transport food
• replace damaged parts
• produce spongin spicules
• form gametes

amoebocyte
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BARREL SPONGES
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• Reproduction
• Most are hermaphrodites-- produce both male and
  female gametes.
• Sexual Reproduction
• Amoebocytes become
• Eggs--retained and fertilized internally
• Sperm-- released through osculum
• sperm ? osculum? other sponges choanocytes?
• amoebocyte carries sperm to egg)? fertilization
  forms larva (plankton)? released from
  mesenchyme, then floats/swims to new spot ?
  develops to adult
• Asexual reproduction is also possible
• gemmules (freshwater sponges only)
• fragmentation (following damage)

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OLD PICTURE FROM FLORIDA OF SPONGE COLLECTORS
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STINGING CELLED

• PHYLUM CNIDARIAN

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• Characteristics of Cnidarians
• Evolved by gaining body symmetry and tissues
• Radially-symmetrical
• no body cavity
• Digestive cavity and mouth for digestion,
  excretion, circulation, and respiration

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• Cnidarian Characteristics
• Cnidocytes -- stinging cells-- barbed /or sticky
  /or poisonous-- used for feeding / protection

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• Gastrovascular cavity-- food and oxygen in /
  waste and CO2 out
• Tissues-- muscular, nervous (sensory and
  nerve-net cells), mesoglea (from ectoderm and
  endoderm)
• Hollow body form(s)-- sessile, vase-shaped polyp
  /or free-swimming, bowl-shaped medusa
• Planula-- free-swimming larval form resulting
  from sexual reproduction (sexual and asexual
  reproduction)

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• Three Classes of Cnidarians
• 1. Hydrozoans-- (Hydra, Portuguese man-of-war,
  Obelia)
• Polyp form
• Mostly asexual reproduction
• Freshwater and marine types

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• 2. Scyphozoans-- jellyfish (stinging nettle, blue
  wasps...)
• Medusa form dominant
• 1/2 inch to 7 feet diameter
• Nerve cells in margin of bell (coordinate
  swimming)
• Sense organs-- statocysts (gravity) and ocelli
  (light)
• Some are edible (juicy mesoglea!)

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Video
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• 3. Anthozoans-- anemones and corals (red coral,
  sea fans)
• Polyp form only (thus sessile except for planula
  and those living on backs of snails)
• Anemones lack skeleton corals secrete CaCO3
  (limestone)
• Many have symbiotic dinoflagellates /or green
  algae
• Sexual and asexual reproduction
• Divided, sophisticated gastrovascular cavity
• Form coral reefs of limestone skeletons-- most
  diverse marine communities-- provide food and
  shelter for fish, shellfish, etc.
• Red coral used for money/jewelry

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