2. Invertebrates Do not have a backbone or vertebral column Range in size from microscopic dust mites to giant squids Include groups of sea stars, worms, jellyfish, and insects 95% of all animals are invertebrates

3. Body Symmetry Radial Symmetry- any number of imaginary planes can be drawn through the center, each dividing the body into equal halves Bilateral Symmetry- can only draw one imaginary plane and it divides the body into two equal halves Asymmetrical Symmetry- cannot put any lines to divide it evenly Cephalization- is the concentration of sense organs and nerve cells at the front end of the body. Usually animals that have bilateral symmetry exhibit cephalization

5. Sponges Sponges are in the phylum Porifera means “pore- bearing” Live their entire adult life attached to one place. They have nothing resembling a mouth, gut and they have no tissues or organ systems. Asymmetrical they have no front or back have no standard form

6. Cnidarians Soft bodied carnivorous animals that have stringing tentacles arranged in circles around their mouths They are the simplest animals to have body symmetry and specialized tissue They have a life cycle that includes two different looking stages: a polyp and a medusa

8. Worms They come in several different types; flat, round and segmented Body cavities there are three kinds acoelomate (no body cavity), pseudcoelomate (fake body cavity), coelomate (real body cavity lined with tissue) Most worms have exhibited cephalization at least enough to call a head Some worms can cause diseases in humans

10. Mollusks Are soft bodied animals that usually have an internal or external shell Include snails, slugs, clams, octopi, and squids Groups of mollusks Gastropods are shell-less or single-shelled mollusks that move by using a muscular foot located on the ventral side Bivalves have two shells that are held together by one or two powerful muscles Cephalopods are typically soft-bodied mollusks in which the head is attached to a single foot, the foot is divided into tentacles or arms

11. Gastropod Bivalve

12. Cephalopods Bivalves

13. Arthropods Have segmented bodies, a tough exoskeleton, and jointed appendages The exoskeleton is made up of chitin that is made from protein and carbohydrates Appendages are things like legs and antennae that extend from the body When they out grow their exoskeleton they go through a period of molting or sheding of their exoskeleton There are 4 subphylum of arthropods or groups

14. Classification of arthropods They are classified based on the number and structure of their body segments and appendages- particullarly their mouthparts The three major groups of arthropods are crustaceans, spiders and their relatives, and insects and their relatives

16. Crustaceans Members of this group are things like crabs, shrimp, lobsters, crayfish, and barnacles Typically have two pairs of antennae, two of three body sections, and chewing mouthparts called mandibles The body sections Cephalothorax- it is formed by fusion of the head with the thorax. Which lies just behind the head and houses most of the internal organs. Abdomen- is the posterior part of the body Carapace- is the part of the exoskeleton that covers the cephalothorax

18. Spiders and Their Relatives These include all spiders, horseshoe crabs, mites, ticks, and scorpions They have mouthparts called chelicerae and two body sections, and nearly all have four pairs of walking legs They have a cephalothorax, and an abdomen. They have the same kind of body structure as crustaceans, but they lack antennae. They have two pairs of appendages attached near the mouth. One pair is called chelicerae contain fangs and are used to stab and paralyze prey. The other pair is called padipalps they are longer and usually modified to grab prey

20. Echinoderms Echinoderms are characterized by spiny skin, an internal skeleton, a water vascular system, and suction-cuplike structures called tube feet. Most adult echinoderms exhibit five-parts radial symmetry. They have appendages that occur in multiples of five Classes of echinoderms include sea urchins, sand dollars, brittle stars, sea cucumbers, sea stars, sea lilies and feather stars

22. Insects and Their Relatives Uniramians are centipedes, millipedes, and insects. They have jaws, one pair of antennae, and unbranched appendages. Insects have three-part bodies (head, thorax, and abdomen) three pairs of legs are attached to the thorax and most are adapted for flight There are two types of metamorphosis incomplete and complete Incomplete they have an adult and an immature stage Complete they have the same stages but within those stages they completely change from one thing to another