1) Kingdom Monera:
Ø It includes bacteria and Eubacteria, mostly tiny, single celled organisms whose genetic material is loose in the cell.
Ø Monera includes most organisms with a prokaryotic cell organization(I.e. without nucleus)
Ø They are filamentous and quite long, green but have no visible structure inside cells.
Ø They absorb nutrients through the cell wall or produce their own food by photosynthesis process.
Ø Monera has been divided into two categories:
· They are prokaryotes that have no true nucleus or any other organelles within their cell.
· Presence of special type of cell wall which helps to withstand extreme conditions.
· Archaebacteria were seen as extremophiles, lived in harsh environment such as hot springs (thermoacidophiles), salt tolerant (halophiles) and those living in high methane habitats like marshlands (methanogens). Methane is used to produce biogas and as sewage treatment.
· Enzymes from extremophile archae can resist high temperature and organic solvents.
· They are large group of unicellular micro-organisms.
· Typically few micrometers in length and have wide range of shapes.
· Bacteria are ubiquitous in nature; growing in soil, acidic hot springs, radioactive waste, water and deep in the earth, in organic matter and in the living bodies of plant and animals.
· There are typically 40 million bacterial cells in gram of soil.
· Chemoautotrophic bacteria generally use inorganic chemicals as the energy source. This energy is achieved by oxidation- reduction process often involving metal ions. This energy is used to convert CO2 into the molecule needed for life.
Ø They are belonging to diverse group of eukaryotic micro organisms.
Ø Term protista was first used by Ernst Haekel in 1866.
Ø Protists were traditionally subdivided into several group based on similarities as Chrysophytes, dinoflagellates, euglenoids, slime moulds.
Ø Protists do not have much in common besides a relatively simple organization either they are unicellular or multicellular without special tissues. This simple cellular organization distinguishes the protists from other eukaryotes ( fungi, animals, plants).
Ø Protists live in almost any environment that contains water. Many protists, algae are photosynthetic and are vital primary producers in ecosystem, particularly in ocean as part of the plankton.
a) Chrysophytes : are golden algae and are large group of heterokont algae found mostly in fresh water.
Ø Most members are unicellular flagellates with either two visible flagella.
Ø Diatoms are major group of chrysophytes (eukaryotic algae) and are one of the most common types of phytoplankton.
Ø Fossilized remains of diatoms over a billion of years form a diatomaceous earth.
b) Dinoflagellates are large group of flagellate protists. Mostly are marine plankton but they are common in fresh water habitats as well.
Ø Their populations are distributed depending on temperature, salinity or depth. About half of all dinoflagellates are photosynthetic.
Ø Mostly are unicellular forms with two flagella; one of these extends towards the posterior end called the longitudiunal flagellum, while the other forms a lateral circle called transverse flagellum.
Ø Red tide is more specifically produced when dinoflagellates are able to reproduce rapidly and explosively on account of the abundant nutrients in water.
Ø They were first defined by Otto Butselli (1884).
Ø They were classified as both animals and plants, as they share characterstics with both.
Ø Euglenoids are one of the best known groups of flagellates.
Ø They are commonly found in fresh water especially when it is rich in organic material.
Ø Many euglenoids have chloroplast and produce energy through photosynthesis, but others feed by phagocytosis or strictly by diffusion.
Ø This varies from rigid to flexible and gives the cell its shape, often giving it distinctive striations. In many euglenoids the strips can slide part one another, causing an incling motion called metaboly.
d) Slime moulds:
Ø Slime moulds feed on micro-organisms in decaying vegetable matter. They can be found in the soil; on lawn and in the forest commonly on deciduous lags.
Ø They begin their life as amoeba like cells. These unicellular amoeba like as commonly haploid and multiply if they encounter their far food bacteria.
Ø When food supplies waves, plasmodium will migrate to the surface of its substrate and transform into rigid fruiting bodies.
Ø The fruiting bodies or sporangia are superficially looks like fungi or moulds but they are not related to the true fungi. These sporangia will then release spores which hatch into amoeba to begin the life cycle begin.
3) Kingdom Fungi:
Ø The fungi are closely related to animals than plants. A fungus is a eukaryote and heterotrophic organism possessing a chitinous cell wall.
Ø Many fungi grow as thread like filamentous microscopic structure called as hyphae and an assemblage of interwined and interconnected hyphae is called mycelium.
Ø Hyphae can be septate or coenocytic (containing one or more nuclei).
Ø Reserve food material is glycogen.
Ø Many fungi produce bioactive compounds called mycotoxins.
Ø Specialized fungal structure important in sexual reproduction is the apothecia, perithecia and cleistothecia in the ascomycetes and the fruiting bodies of the basidiomycetes and few ascomycetes.
Ø In phycomycetes asexual reproduction takes place by producing zoospores (with flagella) or by aplanospores (without flagella). Former one is motile and the later is non-motile. These spores are produced inside a special sac like structure called sporangia. Eg: Mucor, rhizopus, albugo.
They are filamentous fungi composed of hypahe and reproducing sexually via the formation of specialized club shaped and cells called basidia that normally bear external spores which are specialized microspores called basidiospores. Eg: Mushroom, puff balls, jelly fungi, human pathogenic yeast Cryptococcus.
They are commonly called as fungi imperfecti. Fungi producing antibiotic penicillin and those that cause athelete’s foot and yeast infections are example of imperfect fungi. A best known fungus in this phylum is penicillium. Best known product from this genus is penicillin, first widely used antibiotic. Penicillin was first extracted from Penicillium notatum by Alexander Flemming.
4) Kingdom Plantae:
Ø They are eukaryotic and multicellular organisms.
Ø Green plants containing chlorophyll pigment can prepare their own food by using solar energy are called autotrophs.
Ø There are few other species which are heterotrophs like parasites (cuscuta,loranthus)and insectivorous plants.(venus fly trap).
Ø Kingdom plantae includes algae, fungi, bryophytes, pteridophytes, gymnosperms, angiosperms. Among these first three belongs to non-vascular plants and last three belongs to vascular plants.
Ø Non-vascular plants lacks water conducting system of tubular cells (xylem tissue) and do not have the roots , stem and leaves. Non-vascular plants are all placed in the division bryophyte includes mosses, liverworts.
Ø Vast majority of the plant kingdom is vascular cryptogams with tubular water conducting cells called xylem tissue.
Ø A clear alternation of genes is observed with the types of generation representing diploid sporophytic or haploid gametophytic phases in all vascular cryptogams and vice versa in bryophytes.
5) Kingdom Animalia:
· This includes multicellular with specialized eukaryotic heterotrophic organism.
· They have their own means of locomotion and growth is limited, it stops at certain period of age.
· All animals are showing heterotrophic or holozoic mode of nutrition.
· Its example includes sponges, worms, insects, fish, and amphibians.
· Asexual mode of reproduction is restricted to lower forms and all higher organisms shows sexual mode of reproduction.
· Sexual reproduction involves the fusion of male and female gamete resulting in the formation of zygote which undergoes embryonic stages of development and grow into an adult.
Classification of organisms can be explained by following categories like two kingdom, three kingdom, four kingdom, five kingdom and six kingdom.
Viruses are non cellular organisms and act as a connecting link between plants and animals. Lichens are symbiotic association between algae and fungi. Viroids are infectious agents that are smaller than virus.