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How We Organise Life
Biodiversity
Life exists in countless forms, from bacteria to complex animals
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Classification
Organisms grouped by cell structure, number of cells, nutrition and ecological role
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Five kingdoms
Monera, Protista, Fungi, Plantae and Animalia
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Hierarchy and binomial names help us study and conserve biodiversity
- Biodiversity
- Life on the Earth exists in many forms, from simple bacteria to complex animals.
- Criteria
- Organisms are classified by cell structure, number of cells, mode of nutrition and ecological role.
- Five kingdoms
- Whittaker’s system — Monera, Protista, Fungi, Plantae and Animalia — is simple and useful for understanding diversity.
- Plantae
- Divided into five classes — Thallophyta, Bryophyta, Pteridophyta, Gymnosperm and Angiosperm.
- Animalia
- Divided into non-chordata (invertebrates: Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata) and chordata (vertebrates), on the basis of the notochord.
- Protochordates
- Show a transition from invertebrates to vertebrates as they possess a notochord at least once in life.
- Vertebrates
- Divided into fish, amphibians, reptiles, birds and mammals.
- Hierarchy
- Kingdom, Phylum, Class, Order, Family, Genus, Species — each lower level shares more features.
- Binomial nomenclature
- A two-part universal name (genus + species) introduced by Linnaeus.
- Value of classification
- It reveals relationships, traces the history of life and helps conserve biodiversity.
