New NCERT Exploration · Class 9 Science · Chapter 12: Patterns in Life: Diversity and Classification
This chapter is about biodiversity, the huge variety of living organisms on Earth, and why it matters. It explains how and why scientists classify organisms, from Aristotle to the five-kingdom and three-domain systems. It also covers the groups of plants and animals, binomial nomenclature, fossils and the conservation of biodiversity.
From the Class 9 Science Short Notes, made as per the new NCERT book Exploration · Pages 108–132 of the book.
Key points
- Biodiversity is the variety of all living organisms on Earth, including plants, animals, microorganisms and fungi.
- Endemic species are found naturally only in one region, e.g. Nilgiri Tahr, Lion-tailed Macaque, Nepenthes khasiana and Neelakurinji.
- India's biodiversity hotspots include the Himalayas, Western Ghats, Indo-Burma and Sundaland.
- Biological classification groups organisms by similarities and differences, using features like cell type, nutrition, body organisation and DNA.
- R.H. Whittaker (1969) gave the five kingdoms: Monera, Protista, Fungi, Plantae and Animalia.
- Monera are unicellular prokaryotes (bacteria, cyanobacteria); Protista are unicellular eukaryotes (Amoeba, Paramecium, Euglena).
- Fungi are mostly multicellular heterotrophs with a cell wall of chitin and act as decomposers.
- Plantae are divided into Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms.
- Animalia includes invertebrates (Porifera to Echinodermata), protochordates and vertebrates (fish, amphibians, reptiles, birds, mammals).
- Hierarchy of classification: Kingdom → Phylum → Class → Order → Family → Genus → Species.
- Carolus Linnaeus introduced binomial nomenclature: a scientific name has a genus and a species, e.g. Panthera tigris.
- Carl Woese (1977) proposed three domains: Bacteria, Archaea and Eukarya; fossils give evidence of how life changed over time.
Key terms
- Biodiversity: The variety of all living organisms found on the Earth.
- Endemic species: Organisms found naturally only in a particular region and nowhere else.
- Biodiversity hotspot: A region that contains a large number of endemic species.
- Biological classification: The scientific system of grouping organisms by their similarities and differences.
- Binomial nomenclature: The universal two-word scientific naming system introduced by Carolus Linnaeus.
- Notochord: A rod providing internal support, present at least once in the life of protochordates.
- Species: The smallest unit of classification; similar organisms that can interbreed and produce offspring.
- Fossils: Preserved remains or traces of plants and animals found in rocks, sand or mud.
Diagrams to learn
- Endemic species of India
- Map of the major biodiversity hotspots of India
- Classification of organisms chart
- Development of classification systems (Aristotle to five kingdoms)
- Comparison table of Monera, Protista and Fungi
- Examples of Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms
- Examples of invertebrate phyla
- Table of animal adaptations (fish, birds, camel, polar bear, human)
- Levels of classification with tiger and pea plant examples
- Three-domain tree of life
- Rock layers with fossils
- In a scientific name, the genus begins with a capital letter and the species with a small letter; printed names are in italics, and handwritten names are underlined separately.
- Bryophytes are called the 'amphibians of the plant kingdom' because they still need water for reproduction.
- Older rock layers usually contain simpler organisms, while newer layers contain more complex organisms.
A real page from the book
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This page is a summary. The Class 9 Science Short Notes has the complete chapter in colour, with every diagram and worked example.
Frequently asked questions
What are the five kingdoms of classification?
Robert H. Whittaker in 1969 grouped organisms into Monera, Protista, Fungi, Plantae and Animalia. The grouping is based on cell type, cell structure, level of organisation, mode of nutrition and ecological role.
What are the rules for writing scientific names?
A scientific name has two parts, genus and species. The genus starts with a capital letter and the species with a small letter; printed names are in italics and handwritten names are underlined separately.
What are the biodiversity hotspots of India?
The book mentions four hotspots associated with India: the Himalayas, the Western Ghats, Indo-Burma (including North-East India) and Sundaland (including the Nicobar Islands).
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