Marine Invertebrates

Chapter 7

The Classification of Organisms

Domain Bacteria Domain Archaea Domain Eukarya

Kingdom Protista

Kingdom Animalia

Kingdom Plantae

Kingdom Fungi

EukaryotesProkaryotes

Animal Kingdom

• Characteristics of Animals:– Eukaryotic– Multicellular– Heterotrophic – Reproduce sexually– Contain cells lacking a cell wall– Usually capable of movement at some stage in life

Major Phyla of the Animal KingdomPhylum Examples

Porifera Sponges

Cnidaria Jellyfish, sea anemones, corals

Ctenophora Comb jellies

Platyhelmenthes Flukes, tapeworms

Nematoda Roundworms

Annelida Polychaetes, leeches

Mollusca Snails, clams, oysters, octopus, squid

Arthropoda Crustaceans

Echinodermata Sea stars, sea urchins

Chordata vertebrates

Phylum Porifera

• Structurally simplest animal• Do not form true tissues or organs• Mostly sessile – living attached to a surface• Variety of shapes, sizes, and colors• Simple body plan• Filter feed on plankton• Reproduce sexually by broadcast spawning• Some reproduce asexually when buds break off

Sponge Anatomy

http://www.mun.ca/biology/scarr/Porifera.htm

Sponge Anatomy

http://www.enchantedlearning.com/subjects/invertebrates/sponge/labelx/

Sponge AnatomyStructure Function

Pinacocyte

Flat cells covering the outer structure

Pore cells or porocytes

Tube-like cells that allow water to enter

Structure Function

Choanocytes (or collar cells) Cells lining the larger feeding chamber of the sponge; contains a thin flagellum

to create a current and collar to trap food particles

Oculum Large opening on the top of the sponge through which water exits the sponge

Structure Function

Spicules

(http://etc.usf.edu/clipart/47800/47878/47878_spo_spicules.htm)

Used for structural support; transparent siliceous or calcareous

structures of different shapes and sizes

Structure FunctionSpongin

(http://www.palaeos.com/Invertebrates/Lists/Images/Spongin.jpg)

Tough, elastic fibers to help support the sponge

Can be sole means of support or found with spicules

Amebocytes Wandering cellsSecrete the spicules and spongin

Can transport and store food particlesSome can transform themselves into

other types of cells

Sponge Feeding

• Suspensions feeders – animals that eat food particles suspended in the water– Specifically, sponges

are filter feeders, suspension feeders that actively filter the food particles

http://www.mesa.edu.au/friends/seashores/sponges1.html

Sponge filtering - http://www.youtube.com/watch?v=T7E1rq7zHLc

http://www.enchantedlearning.com/subjects/invertebrates/sponge/labelx/

Sponge filtering - http://www.youtube.com/watch?v=T7E1rq7zHLc

Sponge Reproduction

• Asexual (one parent) – when branches or buds break off, they will grow into separate sponges identical to the parent

• Sexual (two parents) – sponges produce sex cells, gametes, nutrient rich eggs and sperm with flagellum– Broadcast spawning

Body Plans

• Sponges have three basic body plans:– Asconoid– Syconoid– Leuconoid

Asconoid• Simplest form• A simple tube perforated by holes• Central cavity, spongocoel, lined with choanocytes

http://animaldiversity.ummz.umich.edu/site/resources/klaus_jost/00017869.jpg/view.html

Syconoid•Large tubular body with a single osculum•Thicker body wall than asconoid•Longer pores that that form simple canals•Canals lined with choanocytes (not central spongocoel)

http://animaldiversity.ummz.umich.edu/site/resources/Grzimek_inverts/Hexactinellida/Euplectella_aspergillum.jpg/view.html http://eastchestereagles.wikispaces.com/Animal+Phyla+Even+Porifera

Leuconoid• Most complex body plan • Vast network of interconnecting canals that

eventually lead to one or numerous larger oscula

<http://animaldiversity.ummz.umich.edu/site/resources/klaus_jost/00000222.jpg/view.html> http://eastchestereagles.wikispaces.com/Animal+Phyla+Even+Porifera

Classes of Porifera

• Three classes of Porifera:– Calcarea– Hexactinellida– Demospongiae

Classes of Porifera• Class Calcarea – includes sponges with all three body plans– produce large spicules (megascleres) of calcium

carbonate.• Classes Hexactinellida– only possess leuconoid members– produce six-pointed large and small spicules (mega-

and microcleres) made of silica.• Class Demospongiae– only possess leuconoid members– may have microscleres and megascleres, spongin, both,

or neither