Five Kingdom Classification system

 Evidence of classification system:

       The classification system of organism was first created by the Greek philosopher Aristotle. Many scientist worked on it including Abu-Usman Umer Aljahiz, Ibn Rushhd, Andrea Casalpino, John Ray, Augustus Rivinus, and Tournefort

Two kingdom classification: 

    The two-kingdom classification divides organisms into two categories: plants and animals. All autotrophs are put into plant group and all heterotrophs are put into group of animal. This system of classification was first classification system and base of other classification. 

Those organisms that can prepar their own food (through photosynthesis and other methods; bacteria use chemosynthesis) are called autotrophs. Bacteria, fungi, algae and plants placed in the kingdom plantae.  Not all autotrophs but some other organisms. However fungi is not autotroph. 

Those organisms which have no ability of preparing food are called heterotrophs. Animals are include in kingdom animalia. 

The flaw of this system is that it ignores significant differences between organisms.   For example euglena has chlorophyll but cell wall is absent. In darkness it get nutrition as heterotrophic.

Three kingdom classification:

    The two-kingdom system was unclear, as demonstrated by the example above. Many taxonomists work on it. In 1866, Ernst Hackle was promote a new kingdom called protista or protoctista. Algae and bacteria was include in this kingdom. But some taxonomist could not satisfy for this system.  For example fungi absorb nutrient through absorption. They are heterotrophs, in their cell wall chitin is found instead of cellulose. These objection led to new theories of classification.

Five kingdom classification:

    After further research, classification system has been evolved.

• In 1937, E-Chatton proposed term of prokaryotes. 
• In 1965 Robert Whittaker suggest five kingdom classification system.
• In 1988, Lynn Margulis and their colleagues research endosymbiosis theory and modified it.

Only Monera includes prokaryotes. 

Prokaryote comes from Greek word Pro means "before" and karyon means "nucleus". This name is used because of they don't have a clear nucleus. 

Other four kingdom include eukaryote. Eu means "true" and karyon means "nucleus" means they have clear nucleus. Organisms are classified on the base of mode of nutrition, motility,

type of reproduction and cellular difference. These five kingdoms are described  below. 

Prokaryote(Monera):

    All prokaryotes are put in this kingdom.. It include all species of bacteria and cyanobacteria.

Characteristics: 

• Some bacteria live as parasites. Some get food by decaying organic matter and other are autotrophs include cyanobacteria. 
• They reproduce asexually by binary fission and through hormogonia.
• Some bacteria are used in medicine.
• But some are pathogens (cause disease).
• Bacteria are found in various environments including soil, water, air, organic matter and even in animals.

Protista(Protoctista):

    Some organisms which behave as fungi, animal and plant like, are include in this kingdom. They are evolved from prokaryote. Some taxonomist thought that all other eukaryotic organisms evolve from major groups. protist. 

This kingdom also known as polyphyletic group of organisms; Poly means "many" and phyletic means "ancestors". These cannot be easily classified but it share some characteristic with other organisms. They are classified into three

1. Animal like protists; All these are unicellular but some are colonial. Some are amoeba, zooflagellates, actinopodes, foraminifera, apicomplexans and cilliates. They can reproduce by binary fission or fragmentation as well as sexually.
2. Plant like protists; These are colonial, multi or unicellular. They all have pigments for preparation of food. Some are Euglenoids, dinoflagellats, diatoms, red, brown and green algae. It is thought that algae is origin and common ancestor of all plants. They can reproduce both sexually(fusion of haploid gametes) and asexually(fragmentation and binary fission).
3. Some protist resemble fungi ; There is no specifically reason to categorize them such as. But both contain thread like structure called hyphae. These are slime molds(Myxomycota) and water mold (Oomycota). They can reproduce by spores.

Besides of this there are more classes of protists and it is more diverse group.

 Fungi(Recyclers or Decomposer):

    Taxonomists suggested that fungi are not suited for the kingdom Plantae, because of several reason. These are similar to plants because they have cell wall and live on soil. They have fruiting body and non motile. 

They are similar to animals because they are autotrophs. Taxonomist separate these organisms from other.

Characteristics:

• It contain cell wall but contain chitin instead of cellulose.
• They are heterotrophs and gain nutrition by absorption in many ways.
• Some are parasites and decomposer. They decay dead organic matter and are called decomposers.
• They are unicellular, multi or colonial.
• Some fungi non motile.
• They can reproduce both sexually(fusion of haploid nuclei) and asexually(via spore formation, budding, fragmentation, and conidia).

There are four major classification of fungi:

• Zygomycota include Rhizopus, Pilobolus.
• Ascomycota include yeast, morels, molds.
• Basidiomycota include mushrooms, rusts, puff balls.
• Deutromycota include Aspergillus, Penicillium, Alternaria.

Plantae:

    Autotrophic organisms are include in kingdom Plantae. There are two main division of plants: Bryophytes and Tracheophytes.

Bryophytes:

    Non-vascular plants means lack xylem and phloem tissues, are called Bryophytes. This is lower classification of plants. plants are believed to have evolved from green algae. They have following characteristic.

• They live in shady and moist places. They need water for reproduction and never live without of water. Because of this reason they are called amphibians of plants. 
• They can reproduce sexually. Archegonia produce non-motile egg and antheridia produce motile sperms. These organs also protect them.
• Bryophytes are divided into Hepticopsida(liverworts), Bryopsida(mosses) and Anthocerpsida(hornworts).

Tracheophytes:

    Tracheophytes have vascular tissue xylem and phloem, that is why it is called vascular plants. These are higher classification of plants.

They are also evolved from green algae.   These have following characteristics:

• Gamete transmission is water-independent.
• They have adaptations for live in many types of habitat. They can live in moist as well as rough and dry land.
• They can differentiate in leaves stem, roots and leaves. They also produce flower and fruits.
• Tracheophytes are divide into Psilopsida, Lycopsida, Preteropsida and Sphenopsida.

Animalia:

    Heterotrophic organisms(animals) are include in Animalia. Animalia is come from Latin word anima which means soul. Animals are evolved from protoctists.

Animals are divided into two division; Radiata and Bilateria.

Dipoblast(The animals which can divide in 4 to many parts and every part is similar to each other) include in grade radiata. For example anemone and jellyfish.

Animals which can divided into two equal parts and one part is similar to other are include in grade bilateria. For example all humans mammals and bird.

General characteristic:

• They are motile and move with different and special organs.
• All they are heterotrophs. 
• They primarily reproduce sexually and few are asexually.
• They are flexible for live in any habitat as compared to other.