Welcome to the Biological Classification. The first chapter describes general characteristics of algae, bryophyte, pteridophyte, gymnosperms, and angiosperms. The second chapter describes general characteristics of porifera, coelenterate, Platyhelminthes, nematode, annelida, arthopoda, mollusca, Echinodermata, protochordata, urochordata, cephalochordate, and vertebrata.