Meet the Invertebrates: Anemones, Octopuses, Spiders, Ants, and Others

It is easy for humans to relate to dogs or other mammals, difficult to see any kinship with flower-like anemones, supple octopuses, or many-legged spiders. Yet we are all animals that have to deal with the basic problems of living. Bodies need to be supported and muscles to pull against firm structures. Instead of skeletons, invertebrates use structures such as exoskeletons and cavities filled with fluid. All animals must catch their food, even if they are fixed in one place, digest their f...