Think of things from the sea... fish, dolphins, whales are what spring to mind. How long did it take before you thought of marine invertebrates? Yet, most sea creatures are invertebrates animals without a backbone. Indeed, the sea harbors animals that are the "missing link" between invertebrates and vertebrates " creatures such as sea squirts and lancelets. But here we are learning about invertebrates. Let's focus on some of the more obvious you would encounter in the Galapagos: bright orange sally lightfoot crabs, chocolate-chip sea stars, and purple-black sea urchins.