Classification of Living Organisms
* A process of gradual and progressive change or development in characteristics is known as evolution.
* Organisms are grouped at various levels: Kingdom, Phylum for animals or
* Division for plants, Class, Order, Family, Genus and Species.
* Kingdom Monera consists of prokaryotic cell consisting of bacteria, small onecelled organisms.
* Kingdom Protista includes unicellular eukaryotic organisms, the simplest of the eukaryotes.
* Kingdom Fungi are eukaryotic organisms which lack chlorophyll. They have to depend on other sources for their nourishment.
* Kingdom Plantae are multicellular eukaryotes with cell walls. They use chlorophyll for photosynthesis.
* Kingdom Animalia includes all organisms which are heterotrophic, multicellular eukaryotes without cell walls.
The Plant Kingdom
* Bryophytes do not have true leaves and roots or special tissues for the transportation of nutrients and water. For example – Moss.
* Pteridophytes have well-differentiated plant body and vascular tissues. For example – Ferns.
* Gymnosperms bear naked seeds and are usually perennial, evergreen and woody. For example – Pines.
* Angiosperms are highly evolved plants with flowers, fruits and covered seeds.
* Plant embryos in Angiosperms are made of Cotyledons.
* Monocots are Angiosperms with a single Cotyledon. For example – Corn.
* Dicots are Angiosperms with two Cotyledons. For example – Bean.