Diversity of Living Organisms and Classification
Diversity of Living Organisms and Classification covers taxonomy, the plant and animal kingdoms, and microbes. The exam tests binomial nomenclature, hierarchy, diagnostic features, and the placement of organisms.
Core rules
- Binomial nomenclature: genus name capitalised, species epithet lowercase; both italicised when printed. Example: Mangifera indica.
- Hierarchy: kingdom, phylum or division, class, order, family, genus, species. Family names end in -aceae in plants and -idae in animals; order names end in -ales in plants.
- Five kingdoms: Monera, Protista, Fungi, Plantae, Animalia. Viruses, viroids, and prions are not included in the five-kingdom system.
- Plant groups: algae, bryophytes, pteridophytes, gymnosperms, angiosperms. Bryophytes need water for fertilisation; gymnosperms have naked seeds; angiosperms have flowers and fruits.
- Animal phyla include Porifera, Coelenterata, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata, and Chordata.
- Microbes include bacteria, archaea, fungi, protozoa, and viruses; lichens are symbiotic associations of algae and fungi.
Worked example
Place Mangifera indica in the taxonomic hierarchy and give its family and order. Reasoning: Mangifera is the genus and indica is the species. The family name takes the -aceae ending, so it is Anacardiaceae. The order takes the -ales ending, so it is Sapindales. The full hierarchy is Plantae, Angiospermae, Dicotyledonae, Sapindales, Anacardiaceae, Mangifera, indica.
Traps
Only the genus is capitalised; the species epithet is not. Viruses are not bacteria and are not placed in the five kingdoms. Lichens are not a single organism. Mycoplasma lacks a cell wall. Bryophytes are called amphibians of the plant kingdom because they need water for fertilisation, not because they live in water permanently.