Cnidaria/Ctenophores

Organization

Tissue level, multicellular

Embryonic Development

Ectoderm → Epidermis

Endoderm → Gastradermis

(Diploblastic)

Symmetry

Radial

Skeleton

Hydrostatic Skeleton

Movement

Polyp (Mouth up): Sessile

Medusa (Mouth down): Motile

Sensory/Nervous

Nerve net, connecting ocelli

Digestion/Feeding

GVC

Cnidocytes to capture prey

Intracellular and Extracellular digestion

Excretory

Diffusion

Circulation

Diffusion

Respiration

Diffusion

Reproduction

Asexual

Sexual

Monoeicious or Dioecious

Classes of Cnidaria

Hydrozoa

Scyphozoa

Cubozoa

Anthozoa

Digestion/Feeding (Ctenophores)

Complete gut/colloblasts

Reproduction (Ctenophores)n

Sexual and Monoecious

Cnidocyte

Penetrate and may inject toxins

Stinger called nematocyst

Hydrozoa

• Dominant Polyp Stage

• Little mesoglea

• Both sexual (Medusae) and Asexual (Polyps) reproduction

Hydra

• Class Hydrozoa

• Exists as an individual polyp

• Mobile

• Freshwater

• Can reproduce asexually or sexually within the same individual

What organism is this?

Hydra

What class is this? What type of reproduction is this? What part is this?

What class is this? What type of reproduction is this? What part is this?

Class: Hydrozoa

Sexual Reproduction (Male)

Testes

What class is this? What type of reproduction is this? What part is this?

Class: Hydrozoa

Sexual Reproduction (Female)

Tentacles

What class is this? What type of reproduction is this? What part is this?

Class: Hydrozoa

Sexual Reproduction (Female)

Ovary

What class is this? What type of reproduction is this? What part is this?

Class: Hydrozoa

Sexual Reproduction (Female)

Basal Disc (Foot)

Obelia

• Class Hydrozoa

• Polymorphic colony

• Have Specialized Polyps

Hydranths (gastrozooids) = feeding polyps

Gonangium (gonozooids) = asexually reproducting polyps

• Both polyp and medusa

• Medusa = Sexual Reproduction

What organism is this? Phyla and class? Name the parts labelled below corresponding to each part.

• Obelia

• Phylum Cnidaria

• Class Hydrozoa

A. Medusa buds

B. Hydranth (gastrozooids) (feeding polyp)

C. Gonangium (gonozooids) (Reproductive polyp)

D. Hypostome

E. Tentacles

F. Perisarc

G. Coenosarc

What organism is this? Phyla and class? Name the parts labelled below corresponding to each part.

• Obelia (Medusa)

• Phylum Cnidaria

• Class Hydrozoa

A. Tentacles

B. Manubrium

C. Radial Canal

Fire Corals

• Class Hydrozoa

• Calcified Skeleton is smooth

• Painful sting, polyps inside skeleton

Portuguese man o’ war (Physalia Physalis)

Class Hydrozoa

Polymorphic Colony

Highly specialized polyps

Venom-filled nematocysts that paralyze prey

Class Scyphozoa

• True sea jelly

• Thick layer of mesoglea

• Medusa is dominant, reduced polyp

What phylum and class is this organism? Label the steps and types of reproduction.

Phyla Cnidaria

Class Scyphozoa

Organism: Aurelia Aurita

A. Sexual Reproduction

B. Planula Larvae (S)

C. Scyhphistoma (A)

D. Asexual Reproduction

E. Strobila (A)

F. Ephyra (S)

Class Cubozoa

• Cube shaped dominant medusa stage

• 4 even tentacles

• Fatal stings

Class Anthozoa

• Sessile with only a polyp stage (no medusa stage)

• Exists as solitary individuals(anemones) or as true colonies (corals)

• Most specialized

• All marine

Organisms in class Anthozoa

• Sea fan (soft coral)

• Sea pansy

• Anemone

• Hard Coral

Phylum Ctenophora

“Comb Jellies”

• Collenchyme (like mesoglea except with muscle cells)

• Colloblasts (cells that adhere to prey and bring to mouth)

• Lack cnidocytes

• HAVE A COMPLETE GUT

• MOSTLY MONOECIOUS

• SEXUAL REPRODUCTION