Ø Sponges are classified into three classes:
1) The document discusses classification of living organisms from early systems proposed by Aristotle, Linnaeus, Haeckel, Whittaker to the modern five and six kingdom systems.
2) It describes the key features of kingdoms - Monera, Protista, Fungi, Plantae and Animalia. It also discusses viruses.
3) The plant kingdom is divided into cryptogams and phanerogams. Angiosperms and gymnosperms are described in detail along with distinguishing features of monocots and dicots.