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

What is the purpose of Bodies filled with holes or pores? 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

Spicules are made of calcium carbonate or silica 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

What do Flagella of choanocytes do? What are spicules made of? 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 Amebocytes also transport carbon dioxide & wastes away from sponge cells Excess water & food leaves through the excurrent osculum

What do flagella do during feeding in a sponge? 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 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 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

How do sponges reproduce? 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

Name two different classes of sponges. Group assessment Name two different classes of sponges.