Of the more advanced living organisms on Earth, the plants evolved before the animals. The oldest plant fossils date from the Precambrian era, over 3 billion years ago. Since the first appearance on Earth of plant life millions of plant species have populated the planet, most of which are now extinct. Today about 3,50,000 species of plants are known, although the true number is probably considerably more, because new species are constantly being discovered and identified.
The classification of plants and animals provides a logical system by which living organisms can be accurately identified. The living organisms are classified into five kingdoms. The five kingdoms are:-
1) Plant Kingdom
2) Animal Kingdom
3) Protista Kingdom
4) Monera Kingdom
5) Fungi Kingdom
The Plant Kingdom or the kingdom Plantae is divided into two sub-kindoms which are:-
1) Cryptogams (Non-Flowering plants) and
2) Phanerogams (Flowering plants)
The Cryptogams are non-flowering plants that are those which reproduce without the means of seeds. Instead of seeds they employ such diverse methods of reproduction as binary fission, conjugation, and spore formation. Cryptogams are divided into three divisions:-
1) Thallophyta
2) Bryophyta
3) Pteridophyta
Thallophyta contains Algae, Fungi, Lichens and Bacteria. Bryophyta contains Mosses, Liverworts and Hornworts. Pteridophyta contains Ferns, Club mosses and Horsetails.
The classification of plants and animals provides a logical system by which living organisms can be accurately identified. The living organisms are classified into five kingdoms. The five kingdoms are:-
1) Plant Kingdom
2) Animal Kingdom
3) Protista Kingdom
4) Monera Kingdom
5) Fungi Kingdom
The Plant Kingdom or the kingdom Plantae is divided into two sub-kindoms which are:-
1) Cryptogams (Non-Flowering plants) and
2) Phanerogams (Flowering plants)
The Cryptogams are non-flowering plants that are those which reproduce without the means of seeds. Instead of seeds they employ such diverse methods of reproduction as binary fission, conjugation, and spore formation. Cryptogams are divided into three divisions:-
1) Thallophyta
2) Bryophyta
3) Pteridophyta
Thallophyta contains Algae, Fungi, Lichens and Bacteria. Bryophyta contains Mosses, Liverworts and Hornworts. Pteridophyta contains Ferns, Club mosses and Horsetails.