Porifera, Cnidarians and Ctenorphora

Sponges Are multicellular Cells do not form permanent tissue –Metazoan organization Sessile – non-motile Radial Suspension feeders, use choanocytes to drive water through canals and chambers Precambrian Classified according to chemical composition of spicules, (internal skeleton)

4 different Classes Calcarea – made of calcite or silica (bony)

Hexactinellida – Glass sponge, found in deep water

Demospongiae – 90%of all sponges

Sclerospongiae – Skeleton made of calcium carbonate.

Anatomy of a typical sponge

Asconoid Sponges

Syconoid Sponges

Leuconoid Sponges

Class Calcarea Skeleton composed of calcium carbonate crystals Simple shapes: vase, pear, or cylinder Marine sponges only

Class Hexactinellida Spicules have 6 rays Marine sponges only Found in deep, cold water

Class Demospongiae 90% of all sponges are this type Marine and freshwater

Key Features Spicules have 4 basic symmetries –Monaxon, triaxon, tetraxon and polyaxon

Multicellular, body is a loose aggregate –Of cells Body has pores, canals and chambers that serve for passage of water All aquatic, mostly marine Radial symmetry or none. Epidermis of flat pinocytes, inner surface of choanocytes that create water current No organs or tissue, digestion intracellular, Excretion and respiration by diffusion No nervous system

All adults are sessile Asexual reproduction by buds and gemmules Sexual reproduction by eggs and sperm Free-swimming larvae

Important Environmental Indicators As filter feeders, if there are toxins/pollutants in the water, sponges are usually the first to suffer, becoming sickly and disappearing….. A great indicator that something is wrong with the marine environment.

Cnidarians 4 classes of Cnidarians Hydrozoa Scyphozoa Anthozoa Cubozoa

Phylum Cnidarian (Coelenterata) knide- needle; arian- having -get their name from cells called cnidocytes which contain the stinging organelles called nematocysts -consist of plant-like hydroids, sea anemones, jellyfish, sea whips, sea fans, hard corals that make up reefs

Cnidarians Cnidarians have: Radial symmetry Diploblastic (double-layer of tissue) Simple, sac-like body Gastrovascular cavity

Two-stage life cycle of Cnidarians are carnivorous: Tentacles around the mouth capture prey animals and push them through the mouth Digestion begins in the gastrovascular cavity with the undigested remains being expelled through the mouth. Tentacles are armed with stinging cells, called cnidocytes

Class Hydrozoa It is a colony of individual medusae and polyps. One contributes a large floating gas sac above the water line Certain polyps have roles: 1.Some are concerned with feeding 2.Some move the colony through the water 3.Some have tentacles to catch fish 4.Some are responsible for reproduction

Class Hydrozoa Hydras, Portuguese Man-of-War Polyp stage X96XS4c&feature=player_embedded

Two-stage life cycle of Cnidarians Adult Medusa (sexual phase) Exists as males or females. Polyp (asexual phase) Produces multiple medusae

Class Scyphozoa

Class Scyphozoa consists of solitary marine medusae called jellyfish because of the jelly- like material of their cell wall The surface of the tentacles are made up of many epitheliomuscular cells. Between these cells are specialized stinging cells called cnidocytes grouped together in “batteries”. Each battery has a nematocyst and when prey brush against the long triggers, venomous threads impales through the flesh

The common jellyfish or Aurelia True jellyfish These often reach a diameter of 30 centimeters The arctic jellyfish can grow to a diamter of 2 meters The mouth is surrounded by oral arms that function in transferring small organisms to the mouth

The stomach has four gastric pouches opening into many radial canals of the umbrella The radial canals lead into the ring canal The canals assure equal distribution of nutrients

Class Scyphozoa Jellyfish yer_detailpage&v=-Tp38DUjUnM

Class Anthozoa

Are marine polyps Some are individuals like sea anemones and some are colonial like coral Corals support themselves by secreting calcium- like skeletons Each polyp generation builds on the previous remains of earlier corals

Fringing coral surrounding a volcanic island

Fringing coral surrounding a subsiding volcanic island

An Atoll- Fringing coral surrounding a submerged volcanic island

Corals- generally found between 30º North and 30º South Need shallow clear water for photosynthesis and warm water for calcium production.

Class Cubozoa box jellies and sea whips Most lethal Survival rate for humans is in minutes /watch?v=SP6TB8kiZB0 m/watch?v=zjHMMmLn gU4

Ctenophora “Comb-bearing” Comb jellies or sea walnuts e=player_embedded&v=G7WT81ukH ZE player_detailpage&v=rHOYatB7c3s

Tentaculata – two tentacles Nuda – no tentacles TWO CLASSES

Ctenophora (tĬnŏf´ərə), a small phylum of exclusively marine, invertebrate animals, commonly known as sea walnuts or comb jellies Ctenophores are characterized by eight rows consisting of ciliated plates called ctenes (combs). Most ctenophores resemble biradially symmetrical jellyfish (phylum Cnidaria) but lack the cnidarian whorl of tentacles around the mouth.Cnidaria They lack the specialized stinging cells (nematocysts) found in coelenterates In order to capture prey, ctenophores possess sticky cells called colloblasts. In a few species, special cilia in the mouth are used for biting gelatinous prey. Have a complete digestive system.

Cnidarian vs. Ctenophora Very diversefew species Fresh & salt waterall marine Radial symmetrybi radial symmetry Have cnidocyteshave colloblasts No bioluminationhave biolumination Incomplete digest syscomplete digest sys No comb platehave a comb plate