40 likes | 178 Views
Lecture 5 Animal Evolution – The Invertebrates. The Evolution of Invertebrates. Sponges : no symmetry, tissues or organs Cnidarians : simple tissues and no organs Flatworms : simplest organ systems Annelids : more pronounced organ systems Mollusks
E N D
The Evolution of Invertebrates • Sponges : no symmetry, tissues or organs • Cnidarians : simple tissues and no organs • Flatworms : simplest organ systems • Annelids : more pronounced organ systems • Mollusks • Roundworms : false coelom, complete digestive system • Arthropods : the most successful • Echinoderms : the junction between invertebrates and vertebrates