An invertebrate is an animal without a backbone An animal with a backbone is called a vertebrate Humans dogs and whales are examples of vertebrates Worms bees and snails are examples of invertebrates Invertebrates live in every part of the world In fact most of the animals on Earth are invertebrates Invertebrates come in all different shapes and sizes WHAT IS A SEA INVERTEBRATE Sponges flatworms jellyfish sea stars spiders shrimp snails and scallops are just a few of the many kinds of invertebrates 4
A sea invertebrate is an invertebrate that lives in the sea There are many different groups of invertebrates that live in the world’s oceans These animals have such features as stinging tentacles spiny skin soft bodies or an exoskeleton Some like sponges are very simple Sponges are merely a mass of specialized cells Others like octopuses are more complex Octopuses can change skin color very quickly and have been observed using tools Based on what you know about vertebrates and invertebrates think of ways that both types of animals are similar In what ways are they different Compare and Contrast Octopuses are known as one of the smartest invertebrates 5
Octopuses belong to a group of invertebrates called mollusks Other mollusks include squid clams and oysters There are more than 150 species of octopus and they live in seas throughout the world Octopuses are considered the smartest invertebrates Octopuses have eight arms and soft baglike bodies with large eyes Their long slender arms reach out in all OCTOPUSES Here you can see the rows of suckers on the underside of an octopus’s arm 6
directions Each arm has two rows of cuplike suckers with great holding power Octopuses vary greatly in size The smallest are only about 2 inches 5 centimeters long The largest may be 18 feet 5 5 meters long and have a 30-foot 9-meter arm span The giant Pacific octopus is the largest and longest-living octopus species The largest ever found weighed 600 pounds 272 kilograms Octopuses have eight arms Can you think of another animal that has eight arms or legs Think About It 7
