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Kingdom Animalia Phylum Cnidaria.

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Presentation on theme: "Kingdom Animalia Phylum Cnidaria."— Presentation transcript:

1 Kingdom Animalia Phylum Cnidaria

2 Characteristics Radial or biradial symmetry Diploblastic organization
Mesoglea between epidermis and gastrodermis Gastrovascular cavity Nerve net Cnidocytes – used in defense and feeding

3 Reproduction/Life Cycle
Can be monoecious or dioecious Alternate generations between polyp and medusa form Polyp – asexual and sessile Medusa – dioecious and free swimming

4 Reproduction Cont’d Planula – Cnidaria larvae
Polyps are produced by budding or planula Medusae formed by budding from a polyp body wall

5 Feeding Use cnidocytes to stun or kill prey
Tentacles contract to bring food to mouth Food is digested in gastrovascular cavity

6 Support and Locomotion
Hydrostatic Skeleton Some classes have longitudinal muscles that aid in movement Polyps – somersault, inchworm, glide on base, and walk on their tentacles Medusae – swim and float

7 Classification Class Hydrozoa Class Scyphozoa Class Cubozoa
Class Anthozoa

8 Class Hydrozoa Mostly marine, but the only class with freshwater members! Alternate generations Mostly colonial polyps

9 Obelia Gastrozooid – feeding polyp formed from planula larvae
Grows through budding into more gastrozooids Gonozooid – reproductive polyp that forms medusa by budding Medusae then reproduce sexually

10 Gastrozooid Gonozooid

11 Gonionemus Medusa predominant
Has a velum (shelf-like lip that projects inward) Velum creates jet propulsion Mouth at end of a manubrium Nerve ring that coordinates swimming movements Statocyst – responds to gravity


13 Hydra Freshwater Polyps only, no medusae Testes form sperm by meiosis
Ovaries form one egg each

14 Physalia Portuguese man-of-war Colonial Cannot swim
Cnidocytes in tentacles are lethal to small vertebrates and dangerous to humans

15 Class Scyphozoa All marine “True Jellyfish” – medusa dominant

16 Stinging Nettle, Mastigias

17 Aurelia Gastrodermal cells have cilia to circulate food
Feeds on plankton Rhopalia – chemoreceptors Lappets – touch receptors Statocysts – gravity sensors Ocelli - photoreceptors

18 Class Cubozoa Medusae are cuboidal Polyps are reduced or absent
Tentacles hang from corners

19 Class Anthozoa Polyps only, no medusae Mouth has a pharynx
Gastrovascular cavity is divided into sections Sexual and asexual reproduction

20 Sea Anemones

21 Corals

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