in family of microbes mainly bacteria , cyanobcateria, fungi, viruses and sub viral particles like viroids and prions are included and they all are studied under microbiology. they all are visible under microscope. apart from native form of microbes genetically modified form of microbes are also studied and many valuable products are produced by them like human insulin, tissue plasminogen factor etc.
so microbiology is not only theoretical subject but it is that theoretical subject which could be directly applicable in practical approaches also.
but how does some one know which organism belongs to which group , how does they take nutrients, how they reproduce etc. so some of scientist took liberty (just a joke ). and classified them in different group so we can study them easily
Two Kingdom Classification :
Entire living world was first time divided broadly in two kingdoms namely “ ragnum Animale” and “ragnum vegetabile “ carlous Linnaeus in 1758. This classification was based on presence or absence of chlorophyll molecule. Later on they were renamed as “kingdom plantae “ and “kingdom Animalia “ But still euglena possesses chlorophyll as well as possesses some features more similar to protozoa also.
Three Kingdom Classification :
Ernest haeckel gave third kingdom name “protist” so haeckel had given concept of three kingdoms classification.He separated unicellular living entities from others.Later on all further diversification and expansion in classification was done on this haeckel’s third kingdom only
Four Kingdom Classification:
Copeland was the scientist who had divided haeckel’s protist in the two sub classes and had given the idea of four kingdom classification system which was later on popularized by Roger Y. stanier in 1958.As per four kingdom classification system protists were divided in upper protista and lower protista
Five kingdom classification :
In 1969, Robert H. whittaker had given the one of the most accepted classification system known as five kingdom classification system which was based on mode of nutrition viz. Photosynthesis,absorptive and ingestion
Kingdom – Monera:
Whittaker’s this kingdom includes the simplest form of microbes. All prokaryotes are included in this kingdom including bacteria and cyanobacteria. Usually their mode of nutrition is found to be absorptive except cyanobacteria which are known to do photosynthesis. They all are devoid of well developed cellular level organisation . they have primitive nucleus . archeaobacteria were also included in this kingdom . the microbes of this kingdom are usually studied in bacteriology.
Kingdom – Protista
This kingdom of whittaker’s classification include mainly eukaryotic microbes’s viz algae and protozoa. Here photosynthesis and ingestion both mode of nutrition are found in algae and protozoa. Respectively . they posses well developed cellular level organisation . they have well developed nucleus. The organisms of this kingdom are studied under phycology and protozoology
Kingdom – fungi
In whittaker’s classification system this kingdom was newly introduced. Fungi were first time inclueded in separate kingdom. As they are quite differ from members of protista by lacking cholorophylls and unable to show ingestion type off mode of nutrition also . they exhibit absorptive type of mode of nutrition . this kingdom mainly contains two types of organisms namely filamentous mycelial molds and unicellular microscopic yeasts. This kingdom has overall economic significance . this kingdom can be studied in branch called mycology.
Kingdom – plantae
This kingdom remains stable since linnaeus’ two kingdom classification system. It includes higher eukaryotes mainly cholorphyllous and having cell wall made up of cellulose here photosynthesis mode of nutrition is found to be prevalent the members of this kingdom are macroscopic in size. All higher plants like bryophytsm pteridophytes etc. they can be studied in botany.
Kingdom – Animalia
This kingdom include all higher animals. They all are higher eukaryotes. The member of this kingdom lack cell wall and having ingestion mode of nutrition. The members of this kingdom can be studied in zoology.