Classification of invertibrates

Answer 1

Invertebrates have nucleated cells and are thus eukaryotes (Domain Eukarya in the Empire of Life). They are multicellular and heterotrophic and thus animalian (Kingdom Animalia). Edward O. Wilson is what one calls a 'splitter' in taxonomy and has split the animal kingdom into about 85 phyla. Most other taxonomists think there are somewhere in the thirties in the realm of 'How many phyla are there ?' Some invertebrate animal phyla are:

Phylum Porifera, Phylum Cnidaria, Phylum Ctenophora, Phylum Platyhelminthes, Phylum Annelida, Phylum Mollusca, Phylum Arthropoda, Phylum Echinodermata, Phylum Hemichordata, Phylum Nematoda, Phylum Rotifera, Phylum Kinorhyncha, Phylum Nemertea, Phylum Bryozoa