Invertebrates Sponges Cnidarians Sponges l Kingdom Animalia Phylum
Invertebrates Sponges & Cnidarians
Sponges l Kingdom: Animalia – Phylum: Porifera (sponges) l l l Simplest invertebrates Asymmetrical (no symmetry!) No tissues, gut or nerves
How Do Sponges Eat? l l Filter feeders: feed on tiny plants and animals Water carries food into the sponge through pores (ostia) – Ostia: holes on the outside of the body l Inside the sponge, collar cells remove food from the water – Collar cells: special cells that line the central cavity of the sponge; they digest food l The water exits through an osculum – Osculum: hole at the top of the sponge
Sponge Anatomy • Where does the water enter? • Where does the water exit? • What structure on the collar cells pushes the water up?
Body Part Abilities l l l If a part of a sponge is broken off, the missing part can regenerate, or grow back If a sponge is broken into pieces, new sponges could form from each piece If you force a sponge body through a strainer, the separated cells could come back together and reform the same sponge!
Kinds of Sponges l l All live in the water (most in salt water) Come in different shapes/sizes Most sponges have a skeleton made of hard fibers called spicules Grouped by their type of skeleton – – Barrel sponge Tube Sponge Finger Sponge Vase Sponge
Cnidarians l l Pronounced “nigh-dare-e-ins” Kingdom: Animalia – Phylum: Cnidaria l l Invertebrates that have stinging cells More complex than sponges – Have complex tissues, a gut & simple nerves l Include: jellyfish, hydrozoa, sea anemones and coral
Two Body Forms l Cnidarians have ONE of the two body forms: – Medusa: swim through the water – Polyp: attach to a surface l Some change forms at different times in their life
Special Cells l All cnidarians have tentacles covered with stinging cells – Nematocysts: stinging cells that release spears into an organism when it brushes the tentacles l l Some can release poison Used for protection and to catch food
Kinds of Cnidarians **We split them into four classes: Kingdom: Animalia Phylum: Cnidaria Class: Hydrozoa Scyphozoa Anthozoa Cubozoa
Hydrozoans l l Hydra, Portuguese Man-o’War Hydra are always polyps (attached) Live in fresh and salt water Many live in colonies
Scyphozoans Jellyfish l Catch other inverts and fish in tentacles l Spend most of their life as a medusa l
Anthozoans l l Sea Anemones and Corals Spend their lives as polyps Often brightly colored Live in colonies
Cubozoans Are square shaped when viewed from above l Resemble true jellyfish l Have well developed eyes l Are one of the most deadliest animals in the ocean l
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