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Chapter 7 Marine Animals sans Backbone. Where are we in geologic time?. So are, we ’ ve moved from bacteria to plankton, and through some alage (seeweed). Now we ’ ll examine primative animals without vertebrae. How are we related??. Introduction.
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Chapter 7 Marine Animals sans Backbone
Where are we in geologic time? So are, we’ve moved from bacteria to plankton, and through some alage (seeweed). Now we’ll examine primative animals without vertebrae.
Introduction • Most (97%) of the amazing life which is located within the oceans, or anywhere else, doesn’t have a backbone! • In every class of invertebrate we can find a marine example…convenient, eh?
Summary of Invertebrates • Sponges-sponge • Cnidarians- “jellyfish” • Comb Jellies- comb jellies • Symmetrical Worms-flat, round, segmented worms • Molluscs-snails, clams, oysters, scallops, octopuses • Arthropods-copepods, shrimp, and lobster • Echinoderms- seastars, brittlestars
1. Sponges • Phylum – Poriferia “pore bearers” • Loose aggregation of specialized cells. • Cells do not actually form organs or tissues, but do serve similar functions, keeping the animal(s) alive.
Porifera-Sponges (the pore bearers) Spicules are like calcium carbonate or silica re-bar for sponges, providing support for a larger congregation.
Sponges • Of the 6,000 known nearly all are marine. • Do they “sits and thinks, or do they just sits??” • Sponges are sessile and remain permanently attached to the substrate they alight upon.
Sponges: Composition • Ostia (tiny pores) – allow water to enter and circulate through series of canals where plankton and organic particles are filtered and eaten • If cells separated, can even regroup and form new sponge • Flexible skeletal frame (spicules) gives spongy texture
Porifera-Sponges (the pore bearers) Spicules are like calcium carbonate or silica re-bar for sponges, providing support for a larger congregation.
Sponges: Composition • Spicules are transparent and made of siliceous or calcareous supporting structures of different shapes and sizes • Skeleton made of protein sponging • Spicules, spongin, or both
Sponges: Composition • Wandering cells, amebocytes, secrete spicules and sponging, transport and store food particles, and transform into other types of cells to quickly repair damage
Porifera-Sponges (the pore bearers) Spicules are like calcium carbonate or silica re-bar for sponges, providing support for a larger congregation.
Still, if you carve ‘em up, they come back for more!! It’s more amazing than that. If you mix groups of sponges together, they will usually reorganize into their original groups.
Sponges: Feeding • Outer surface covered with flat cells called pinacocytes and pore cells (porocytes) which allows water to enter • Water pumped into larger feeding chamber lined with collar cells (choanocytes) • Each choanocytes have flagellum that creates currents and a thin collar that traps food particles, which is ingested by body of cell
Sponges: Feeding • Water leaves through osculum, large opening at top of sponge
Sponges: Reproduction • Asexually • If piece breaks off, it can form new sponge • Sexually • Specialized collar cells or amebocytes can turn into gametes • Large nutrient rich egg and smaller sperm with flagellum
Sponges: Reproduction • Most are hermaphrodites • Some have separate male and female organisms • Typically utilize broadcast spawning • Egg retained inside body until fertilization
Sponges: Reproduction • Early development takes place inside • Flagellated sphere of cells (larva), parenchymula, is planktonic • Settles and metamorphosis into juvenile
Reproduction: Asexual vs. sexual Damage to a sponge can actually promote asexual reproduction, as “parts” can land elsewhere and form new sponges.
General Sponge Types Hawaiian encrusting sponge Sclerosponge (CaCO3) Ceratoporella nicholsoni Sponges fall into several basic categories, mostly depending on Shape, ranging from tropics to poles: branching tubular round encrusting glass boring (destructive)
Sponges: Diversity • Branching and Tubular – volcano-like masses • Encrusting – thin and brightly colored on rocks • Glass – anchored in deep water sediments • Siliceous spicules (lace like) • Boring – bore into calcium carbonate (oysters and corals) • Sclerosponges (coraline) – calcium carbonate skeleton forms beneath body of sponge
Sponges: Diversity • Bath sponges • Harvested in Gulf of Mexico and Mediterranean • Spongin are the fibers that remain after the death of the sponge