Vertebrates and Invertebrates ​
All animals are classified into groups according to things they have in common with other animals in that group. The first major difference that separates groups of animals is whether or not they have backbones. Animals with backbones are called vertebrates. Animals without backbones are called invertebrates. Each of these groups is divided into even smaller groups. Examples of groups of invertebrates are sponges, flatworms, roundworms, segmented worms, mollusks and arthropods. Sponges Sponges are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them. Flatworms The flatworms are a phylum of relatively simple unsegmented, soft­bodied invertebrates. ​
They have heads and tails but do not have true organs like stomachs, lungs, etc. Roundworms The r roundworms are a diverse animal phylum living in a very large range of environments. Roundworms have round bodies, a digestive system and a nervous system Segmented Worms Segmented worms are more complex than flatworms and roundworms. Earthworms are one example of segmented worms. They have eyes, organ systems and even jaws. Mollusks Most mollusks have a soft, skin­like organ covered with a hard outside shell. Some mollusks live on land, such as the snail and slug. Other mollusks live in water, such as the oyster, mussel, clam, squid and octopus. Arthropods Arthropods are the largest group of animal on earth. Insects, spiders, centipedes, millipedes, lobsters and crabs are all arthropods.​
An arthropod is an invertebrate animal having an exoskeleton, a segmented body, and jointed appendages. . There are five major groups of verfebrates QUESTIONS 1. Animals are classified into different groups according to a. whether or not they have backbones. b. whether they have hair or feathers. c. whether or not they feed their young milk. d. All of the above 2. Invertebrates a. have backbones. b. do not have backbones. c. live only in water. d. is a group of animals that includes simple fish. 3. List six groups of invertebrates 4. The most complex group of worms are a. roundworms b. segmented worms c. flatworms d. snakes 5. List three types of mollusks. 6. The largest group of animals on earth is the ___________________ group. Vocabulary Word Definition/translation vertebrate invertebrate oragnism segmented/ unsegmented Systems digestive nervous organ exoskeleton appendages affixes/roots in­ ​
in​
vertebrate not un­ ​
un​
segmented not ex­ ​
exo​
skeleton out