why spirogyra and chlamydomonas are not included in protista ?
- Earlier classification systems included bacteria, blue green algae, fungi, mosses, ferns, gymnosperms and the angiosperms under ‘Plants’.
- The character that unified this whole kingdom was that all the organisms included had a cell wall in their cells.
- This placed together groups which widely differed in other characteristics. It grouped together the unicellular organisms and the multicellular organisms. Example: Chlamydomonas and Spirogyra were placed together under algae.
- All single-celled eukaryotes are placed under Protista, but the boundaries of this kingdom are not well defined.