sponges cnidarians ctenophores. phylum porifera: the sponges

Parazoa and RadiataSponges

CnidariansCtenophores

Phylum Porifera: The Sponges

General InformationMainly marine organisms;

evolved from choanoflagellates

May have algae or bacteria that give them color

Larva are flagellated, adults considered sessile

Many disease-fighting compounds

holdfast

Tube Sponges

Encrusting Sponges

CharacteristicsCan reproduce sexually

or asexually

Gas exchange and excretion - diffusion at individual cells

Supported by skeletal fibers:

spicules or spongin

Simple animals made of few specialized cells; NO tissues

Asymmetrical

Body with ostia

Most are filter feeders / suspension feeders 1 family is

carnivorous

Anatomy of a Sponge:

OsculumSpongocoelChoanocyteAmoebocyteMesohyl

Suspension Feeding & Gas Exchange

Sponge Reproduction:Asexual reproduction

Buds or gemmules

Sexually – most sponges are hermaphroditesCells become egg/spermSperm released into waterFertilization occurs in mesohyl

(egg)Zygote becomes flagellated larva

that leaves in flow of water

Phylum CnidariaJellyfish

Box jelly

Coral

Sea anemone

Main CharacteristicsDiploblastic, radial symmetry

Cnidocytes with nematocysts concentrated in tentacles

Gastrovascular cavity with 1 opening2 layers separated by mesoglea

Gas exchange and excretion occur by diffusion

Structure cont…Nerve nets

Connect sensory cells to contractile cellsSense organs around edge of bodyEx. photoreceptors

Contractile cells Not true musclesAct as hydrostatic skeleton

Cnidarians come in 2 forms:Medusa – tentacles

downPolyp – tentacles

up

Many alternate between medusa and polyp during life cycle

4 Classes of Cnidaria

Hydrozoa Scyphozoa Cuboza Anthozoa

Cnidarians are CarnivoresFeed on fish, larva, comb jellies, other

zooplankton

Sting prey with their tentacles

Mouth gastrovascular cavity mouth

Jellyfish.asf

A word about corals:Many have symbiotic zooxanthellae

Environmental issue: Coral Bleaching

Interesting Facts…Portuguese Man-

of-WarColonial

Has sail-like float

Tentacles can grow up to 165 feet and are nearly invisible

More interesting facts…Box Jellies

More toxic than Man-of-War

Stings can lead to heart failure within minutes

Tentacles may reach 15 feet

CTENOPHORA: THE COMB JELLIESDiploblastic??; Biradial

Symmetry

Swim with 8 rows of ciliary combs

Have 2 long tentacles with sticky cellsColloblasts

Eat large amounts of fish larva & planktonMouth + 2 anal pores

Introduced/Invasive species (Black Sea)