SPONGES, CNIDARIANS,& CTENOPHORES

PHYLUM PORIFERA CHARACTERISTICS Includes marine & freshwater sponges Found in the kingdom Animalia & subkingdom Parazoa Sessile as adults Simplest of all animals

SPONGES CHARACTERISTICS CONTINUED Contain specialized cells, but no tissue Asymmetrical Bodies filled with holes or pores for water circulation Marine sponges are larger & more colorful than freshwater sponges Range in size from 2 centimeters to 2 meters

GROUP ASSESSMENT What is the purpose of Bodies filled with holes or pores? How big can they get?

SPONGES CHARACTERISTICS CONTINUED Osculum is single, large body opening at the top for water & wastes to leave Spongocoel is the body cavity of sponges Have only 2 cell layers (ectoderm & endoderm) separated by jellylike material Flagellated cells called choanocytes or collar cells line their internal body cavity Flagella of choanocytes beat & pull in water containing food which the collar traps

SPONGES CONTINUED Spongin is a network of flexible, protein fibers making up the sponge's skeleton Spicules are tiny, hard particles shaped like spikes or stars in the skeleton of some sponges Spicules are made of calcium carbonate or silica

GROUP ASSESSMENT What do Flagella of choanocytes do? What are spicules made of?

FEEDING IN SPONGES Sponges are filter feeders that remove plankton (food) from the water that is brought in through pores lined with collar cells Flagella pull in bacteria, protozoans, & algae that sticks to collar of choanocytes where it is digested Amebocytes are specialized cells in sponges that can roam to pick up food from choanocytes & distribute it to all other parts of the sponge

FEEDING IN SPONGES Amebocytes also transport carbon dioxide & wastes away from sponge cells Excess water & food leaves through the excurrent osculum

GROUP ASSESSMENT What do flagella do during feeding in a sponge? Where does the excess water and food go in a sponge?

REPRODUCTION IN SPONGES Sponges can reproduce asexually by external buds that break off & form new sponges or stay attached to form sponge colonies Gemmules are specialized, internal buds formed by sponges during cold or dry weather that can survive harsh conditions

REPRODUCTION IN SPONGES Gemmules consist of a food-filled ball of amebocytes surrounded by a protective coat with spicules & released when adult sponge dies Gemmules break open when conditions improve & the cells form new sponges

REPRODUCTION IN SPONGES Sponge can also asexually regenerate missing parts or a new sponge from a small piece of sponge Sponges are hermaphrodites (produce both eggs & sperm), but they exchange sperm & cross-fertilize eggs during sexual reproduction

REPRODUCTION IN SPONGES Planula is the flagellated, free- swimming larva that forms from the zygote Planula larva eventually settles to the bottom & attaches to develop into an adult, sessile sponge

GROUP ASSESSMENT How do sponges reproduce? What does it mean that sponges are hermaphrodites ?

CLASSES OF SPONGES Calcarea are chalky sponges with calcium carbonate spicules Hexactinella includes glass sponges & the Venus flower basket with silica spicules Demospongiae include horny & bath sponges with only spongin or spongin & silica spicules Sclerospongiae are coral sponges & have spongin & silica and calcium carbonate spicules

GROUP ASSESSMENT Name two different classes of sponges.

PHYLUM CNIDARIAN CHARACTERISTICS Includes marine organisms such as jelllyfish, Portuguese man-of-war, coral, sea anemone, & sea fans Hydra is a freshwater cnidarian All carnivorous Have 2 cell layers (epidermis -outer & gastrodermis-inner) with a hollow body called gastrovascular cavity

PHYLUM CNIDARIAN CHARACTERISTICS Contain a jelly-like layer between epidermis & gastrodermis called mesoglea Single opening (mouth/anus) to gastrovascular cavity where food & water enter & wastes leave; called two-way digestive system Have tentacles around mouth to pull in water & capture food

CNIDARIAN CHARACTERISTICS Have a simple nerve net with to help with movement & senses Sessile members include corals, sea anemones, & sea fans Have radial symmetry as adults Contain stinging cells called cnidocytes in their tentacles that contain coiled stingers called nematocysts that can shoot out & paralyze prey

GROUP ASSESSMENT 1. What is a hollow body cavity called in a cnidarian? 2. What kind of digestive system does an cnidarian have?

BODY FORMS Polyp forms are usually sessile with upright tentacles arranged around the mouth at the top and with a thin layer of mesoglea Polyps are the asexual stage Corals, hydra, & sea anemones exist in the polyp form as adults

BODY FORMS Medusa forms are usually free- swimming, bell-shaped animals with tentacles that hang down around the mouth and with a thick layer of mesoglea for support Medusa are the sexual stage Jellyfish & Portuguese man-of-war are medusa form as adults

BODY FORMS Some cnidarians are dimorphic or go through both polyp & medusa stages in their life cycle Some are solitary (Hydra) others are colonial (corals) Three classes include Hydrozoa (hydra), Scyphozoa (jellyfish), & Anthozoa (sea anemones & corals)

BODY FORM PICTURES

GROUP ASSESSMENT What are the two body form stages of a cnidarian called? What body form do corals exist as adults? What body form do jellyfish exist as adults?

HYDROZOA Includes freshwater, sessile hydra (exists only as polyps) Portuguese man-of-war (exists as colony of polyps & medusa) Group of cells called basal disk produces sticky secretion for attachment & can secrete gas bubbles to unattach & let hydra float Hydra also move by somersaulting (tentacles bend over to bottom as basal disk pulls free)

HYDROZOA Tentacles pull food into gastrovascular cavity where enzymes digest it Reproduce asexually by budding during warm weather & sexually in the fall Hermaphrodites that release sperm into water to fertilize eggs of another hydra

GROUP ASSESSMENT What are two examples of organisms that fall in the Hydrozoa class? What method do they reproduce during the warm weather and then during fall?

SCYPHOZOA Includes bell-shaped jellyfish Medusa stage is dominant in the life cycle Tentacles may be meters in length & carry poisons that cause severe pain or death Have both asexual polyps & sexual medusa stages in their life cycles

SCYPHOZOA Adult medusa stage releases eggs & sperm into water Fertilization produces ciliated planula larva that settles to the bottom, attaches, & forms tentacles New medusa bud off of reproductive polyps & form adult jellyfish

JELLYFISH

GROUP ASSESSMENT Which stage dominates the scyphozoan class? What do new medusa that bud off produce?

ANTHOZOA Include corals in a limestone case & sea anemones Called "flower animals" All marine Sea anemone is a sessile, polyp- form that uses its tentacles to paralyze fish

ANTHOZOA Some anemones in the Pacific Ocean live symbiotically with the clownfish sharing food & protecting each other Corals are small, colonial polyps living in limestone cases Coral reefs form as polyps die & provide a home and protection for other marine animals

ANTHOZOA notes Reefs form in warm, shallow water & only the top layer has living polyps Algae may live symbiotically with coral supplying them with oxygen NEMO!

GROUP ASSESSMENT What two organisms identify the Anthozoa class? What is unique about the relationship between clownfish and sea anemone?

PHYLUM CTENOPHORA CHARACTERISTICS All marine Includes comb jellies Have eight rows of fused cilia called "comb rows" Largest animal to move by cilia Move by beating cilia Lack cnidocytes but have cells sticky cells called colloblasts that bind to prey

PHYLUM CTENOPHORA CHARACTERISTICS Colloblasts located on two ribbon-like tentacles Have sensory structure called apical organ to detect direction in the water Most are hermaphrodites (make eggs & sperm) Produce light by bioluminescence

GROUP ASSESSMENT What is the name of the organism that is unique to class Ctenophora? What is the name of their ability to produce light?