ANIMAL KINGDOM : BASIS OF CLASSIFICATION
Animals are heterotrophic, multicellular organisms devoid of chlorophyll and cell walls. Animalia has eleven main phyla: For detail notes 1. Porifera 7. Invertebrates 2. Cnideria 8. Mollusca 3. Ctenophora 9. The echinodermata 4. Hemichordata 10. Platyhelminthes 5. Aschelminthes 11. Chordata 6. Annelida CLASSIFICATION BASIS 1. Organizational levels Animals are categorized into four levels based on this: a.At the cellular level of organization, cells are grouped together loosely. For instance, Porifera. b. The organizing of cells into tissues occurs at the tissue level. For instance, ctenophores and nidarians. c. Organ level organization: Tissues are grouped into organs at this level. For example, higher animals (from chordates to platyhelminthes). d. Organ system level of organization: In this case, an organ system is linked to an organ. Every system carries out a particular physiological task. Consider higher ani...