Our planet is home to millions of creatures From sea turtles to snakes to snow leopards Earth’s habitats are filled with animals that are interesting and diverse including mollusks There are many fascinating animals within the group of mollusks Mollusks share many things in MEET THE MOLLUSKS This coconut octopus is just one of the many mollusks that call Earth home 4
common yet there are also many differences between them Most mollusks live in water though some live on land Many mollusks have shells but some do not In fact some mollusks such as snails and squid seem too different to belong to the same group Millions of mollusks populate our planet They live in diverse environments all over the world Mollusks have certain characteristics that set them apart from other animals and each other Let’s dive into the world of mollusks to learn more about them Mollusks live in many different environments including rivers Habitats are places or type of places where a plant or animal naturally lives or grows Vocabulary 5
A mollusk is a kind of animal with a soft body Most mollusks have a hard shell that protects their body but not all do There are more than 100,000 species or kinds of mollusks in the world Scientists think they account for 23 percent of all known sea animals With so many mollusk species it’s no surprise how different they are But they do have some traits in IDENTIFYING MOLLUSKS This Carpathian blue slug creeps along a pile of moss 6
common Mollusks are invertebrates which means they do not have a backbone and their bodies are not divided into sections Generally mollusks have three body regions a head a visceral mass and a foot-like structure The head contains the brain The visceral mass contains the organs It is surrounded by a protective layer called the mantle In some mollusks the mantle forms the animal’s shell A mollusk’s foot helps it move or dig Why do mollusks need to have a hard shell What could happen without it Think About It More than 90 percent of all animals are invertebrates including jellyfish starfish snails shrimp and more 7
