The classification of all living organisms follows the following hierarchy
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Carolus Linnaeus classified organisms into two broad kingdoms, namely plants and animals only. However, not all living organisms are either plant or animal. Some organisms are neither plant nor animal. Therefore, the five kingdom of classification was developed.
All living organisms can be classified into these five kingdoms:
- Kingdom monera
- Kingdom protista
- Kingdom fungi
- Kingdom plantae
- Kingdom animalia
Monera Kingdom
Members of this kingdom are unicellular, prokaryotic (no true nuclear membrane or membrane-bound organelles) and their cell wall do not contain cellulose. Examples includes; blue-green algae and bacterial
Kingdom Protista
They are unicellular organisms, eukaryotic (has definite nuclear membrane or membrane-bound organelles), they move by either cilia or flagella. They reproduce asexually by mitosis and sexually by fission of the gamates. Members of this kingdom includes Amoeba, Paramecium, and Euglena.
Kingdom protista is divided into four phyllums namely; protozoa, pyrrophyta, euglenophyta, and chrysophyta.
Fungi Kingdom
Fungi is closely related to plants, however fungi differ from plants with the possession of chitin in their cell wall instead of cellulose.
Fungi are eukaryotic (cell with nuclear membrane or membrane-bound organelles), they are non-green plants (lack chlorophyll) have cell wall made of chitin, have no true roots, stems, and leaves.
Some fungi are unicellular (e.g yeast), while some fungi are multicellular (e.g mushroom). Fungi reproduce asexually by spore formation and sexually by conjugation, their vegetative parts are made up of fine and delicate threads called hypae e.g mushroom, yeast, and rhizophus.
Kingdom Plantae
Plant kingdom is divided into three phyllums namely; (1) Thallophyta (2) Bryophyta (3) Tracheophyta
Thallophytes:
Are microscopic plants which have no true roots, stems, and leaves. They have cellular cell wall, some are unicellular (chlamydomynas) while others are multicellular (e.g spirogyra). They also live in colonies e.g volvox.
Bryophytes:
Are multicelliular green plants, that lack true roots, stems, and leaves. They posses asexual reproduction by spores, in which there is alternation of generation. E.g mosses and liverworth,
Tracheophytes
Are vascular plants grouped into two sub-divisions: pteridophyta and spermatophyte
Pteridophyta are multicellular, vascular green plant which are non-flowering plants. E.g ferns.
Spermatophyta are multicellular, seed producing flowing plant, which are divided into gymnosperm and angiosperm. The gymnosperm produces naked seeds, without flowers. E.g cycads, and conifer. The angiosperm produces enclosed seeds in their fruit. Angiosperm is further divided into dicotyledons and monocotyledon plants.
Dicots bears seeds with two seed leaves or cotyledons, while monocots bears seeds with only one seed leaf or cotyledon
Animal Kingdom
This is the kingdom for all the vertebrates and invertebrates animals (animals without backbones).
The animal kingdom is divided into eight phylum namely:
- Porifera
- Coelenterata
- Platyhelminthes
- Nematoda
- Annelida
- Mollusca
- Arthropoda
- Echinodermata
- Chordata
Examples
- The type of asexual reproduction that is common to both paramecium and protest is A. budding B. sporulation C. fragmentation D. fission (ans)
- The domination phase in the life cycle of a fern is the A. gametophyte B. prothallus C. sporophyte (ans) D. antheridium
- The fungi are distict group of eukarotes mainly because they have A. spores B. no chlorophyll (ans) C. many fruiting bodies D. sexual and asexual reproduction
- The organ which is sensitive to light in euglena is the A. gullet B. flagellum C. chloroplast D. eyespot (ans)
Five Kingdom Classification: WAEC Biology Past Questions (Practice)
Attempt the practice questions below, to evaluate your knowledge of the topic so far
