Class IX Science
Notes for Diversity in Living Organisms
• Biodiversity refers to variability.
• The diverse forms of organism need classification.
• The evolutionary history decides the phylogenetic classification.
• H. Whittaker proposed the five kingdom system of classification
• A distinct name is a need for identification.
• Common names are unscientific.
• Binomial nomenclature is scientific naming of organisms.
• Taxonomic hierarchy is the framework of classification which helps in appropriate placing of organisms.
1. Monera
• These are prokaryotic, unicellular, autotrophic or heterotropic organisms.
2. Protista
• These are unicellular and eukaryotic, autotrophic or heterotrophic organisms.
• They are further classified as protistan algae, slimemoulds, and protozoa.
3. Fungi
• Multicellular and eukaryotic organisms having plant like and animal like features. They may be parasitic or saprophytic.
4. Plantae
• These are multicellular, eukaryotic and autotrophic organisms. They are further classified.
• Thallophyta – Thallus like body, mostly autotrophic and aquatic.
• Bryophyta – Simple plants with no vascular system. They are amphibious.
• Pteridophytes – They are land plants with true vascular system.
• Gymnosperms – They are land plants bearing naked seeds.
• Angiosperms – They are flowering plants with seeds covered by fruits.
5. Animalia
• These are multicellular, eukaryotic and heterotrophic organisms. They are further classified.
• Porifera – Pore bearing organisms.
• Coelenterata – Organisms with hollow gut.
• Platyhelminthes – unsegmented flat worms.
• Nematoda – Unsegmented round worms.
• Annelida – Metamerically segmented worms.
• Arthropoda – These are animals with jointed appendages.
• Mollusca – Soft bodied animals.
• Echinodermata – Spiny skinned animals.
• Chordata – Dorsal nerve cord,
notochord and gill slits.