Download Chapter 17 - Invertebrates Invertebrate – an animal that does not

Chapter 17 - Invertebrates
Invertebrate – an animal that does not have a backbone.
Vertebrate – an animal that has a backbone
Bilateral Symmetry – has one line of symmetry, both sides are exactly the same.
Radial Symmetry – has more than one line of symmetry.
Asymmetrical – no lines of symmetry.
Filter Feeders – take out tiny organisms and oxygen from the water as it passes over the sponge.
Flagella – thin, whiplike structures that help move water over the sponge.
Tentacles – surround the mouth of some cnidarians. Have stinging cells on the end of them.
Polyp – vase shaped body of a cnidarians that is attached to the ground
*example – sea urchin and sea anemones
Medusa – bell shaped body of a cnidarians that can swim or move
*example – jellyfish
Parasite – an organism that lives on or in another organism. Depends on that organism to get food and
shelter.
Host – an organism that a parasite lives on or in. Is harmed by the parasite.
Gills – organ that allows a water-dwelling animal to exchange carbon dioxide for dissolved oxygen in the
water.
Mollusk – soft bodied, bilaterally symmetrical invertebrate with a large, muscular foot, a mantle, and an open
circulatory system. Usually has a shell
Mantle – thin layer of tissue that covers a mollusk’s body and that can secrete a shell.
Radula – scratchy, tonguelike organ in many mollusks that has rows of teethlike projects used to scrape and
grate food.
Closed Circulatory System – a type of blood circulation system in which blood is transported through blood
vessels rather than washing over organs.
Open Circulatory System – a type of blood circulation system that lacks blood vessels and in which blood
washes over the organs.