Introduction to Simple Invertebrates

Slide1Simple Invertebrates• Sponge • Sponges are asymmetrical • and do not have real tissue or organs. • Cnidarians have radial symmetry • and have a mouth, tentacles, muscle tissue and stinger cells sponge jellyfish Sea anemone hydra coral

Slide2Simple Invertebrates• Flatworm -flat body, head with simple eyes, and a mouth • Roundworm-simple digestive and nervous system • Segmented worm- divided into sections and has organs such as a heart, stomach, and brain Flatworm Roundworm (nematode) Segmented worm (annelids)

Slide3Complex Invertebrates -Mollusks• Snails • have bilateral symmetry • a muscular foot or tentacle • mass of internal organs • most have a shell • specialized organs including heart, gills and a well-developed nervous system Snails clams squid

Slide4Complex Invertebrates-Echinoderms• have a hardened skeleton inside the body (endoskeleton) • usually have radial symmetry • use a water pressure system that helps them feed, breathe and move Sea star Sea urchin Sea cucumber

Slide5Complex Invertebrates -Arthropods• crabs • hard skeleton on the outside (exoskeleton) provides strength and protection. • bilateral symmetry • segmented bodies with jointed legs • efficient nervous sytem and good sensory systems insects spiders crabs