Exploring Our Fluid Earth

This introduction to invertebrates gives an overview of the concepts and activities explored in this unit and describes how these investigations build an understanding of ocean literacy.

Invertebrates are animals without backbones. They represent the vast majority of all animal species on Earth.

Invertebrates are a collection of many groups within the animal kingdom. They represent a wide diversity of forms and evolutionary innovations.

A diversity of body plans offer invertebrates multiple solutions to the problems of surviving on Earth.

All species of sponges fall within the phylum Porifera. Although they cannot move, sponges are actually active animals.

Cnidarians are a diverse group of animals with stinging cells. Examples include jellyfish, anemones and corals.

The long, tubular, worm-like body plan is one of many evolutionarily successful designs repeatedly employed by invertebrates.

Molluscs represent a very large and diverse group of invertebrates. Examples include snails, clams, and squid.

Arthropods represent the largest animal phylum. Examples include insects, spiders, crabs, and shrimp.

Echinoderms can be generally distinguished by their bumpy skin or sharp spines and five-sided radial symmetry.

Phylum Chordata consists mostly of vertebrates, but also includes two invertebrate groups: tunicates and lancelets.