Biological Classification

 Biological Classification

INTRODUCTION: In this chapter, Biological Classification we will discuss in detail. Arranging organisms into groups on the basis of affinities in the hierarchy.

• Help to know the relationship between the organisms of different groups.
• Arrange the species in the different categories on the basis of similarity or dissimilarity.
• Help in the identification of organisms.

Artificial System	Natural System
It employs one or two morphological traits.	It employs many morphological characters.
Do not employ characters biochemistry, cytology, genetics, etc of organisms.	Employs all these characters.
Do not provide information about natural relationships.	It Provides information on natural relationships.
This system uses habit or habitat for classification.	But this the system never uses habit or habitat for classification.

    Table 1: Differences between Artificial and Natural System of Classification

Taxonomy Branch	Information
Cytotaxonomy	Provide comparative cytological studies, number, structure, and behavior of chromosome
Chemotaxonomy	Provide information of various chemical constituents like alkaloids, crystals, betacyanin, proteins, amino acids, etc.
Numerical taxonomy	Provide largely number of statistical like numbers and codes
Cladistic taxonomy	Provide similarity due to common ancestor

    Table 2:  Major Branch of Taxonomy

*Biological Classification

S.NO.	Characters	Monera	Protista	Fungi	Plantae	Animalia
1	Cell type	Prokaryotic	Eukaryotic	Eukaryotic	Eukaryotic	Eukaryotic
2	Cell wall	Non- cellulosic	Present in some	Present (Non cellulosic)	Present(cellulose)	Absent
3	Chloroplast	Absent	Present in some	Absent	present	Absent
4	Mitochondria	Absent	Present	Present	Present	Present
5	Nuclear membrane	Absent	Present	Present	Present	Present
6	Motility	Bacterial flagella	Cilia, flagella amoeboid	Cilia, flagella in some	Cilia and Flagella in lower forms	Cilia and flagella
7	Mode of nutrition	Autotrophic chemo and photosynthetic	Photosynthetic and heterotrophic	Heterotrophic, saprophytic and parasitic	Autotrophic by photosynthesis	Heterotrophic by ingestion

       Table 3: Characteristics of Five Kingdom

See Also: Diversity Living World

 Whittaker proposed five kingdoms Monera, Protista, Fungi, Plantae, and Animalia.

1. Kingdom Monera: Mycoplasma, bacteria, actinomycetes, spirochaetes, rickettsiae, chlamydiae, and cyanobacteria.

•  They are basically unicellular.
• Nutrition - parasitic, photoautotrophic, symbiotic, etc.
• The cell wall is generally present.
• Genetic material is not organized.
• DNA is naked.
• Membrane-bound cell organelles are absent.
• Mitotic spindle and Gametes are absent. 
• A) Archaebacteria: Primitive group of bacteria.
• Groups of Archaebacteria: a) Methanogens b) Halophiles c) Thermoacidophiles
• B) Eubacteria: Typical prokaryotic
• a) Coccus bacteria: spherical, small and non-flagellated
• b) Bacillus: rod-shaped
• c) Vibrio: comma-shaped
• d) Spiral: coiled form 

Image 1: Bacteria

See Also: Monera Bacteria Archaebacteria Cyanobacteria

Protista Photosynthetic Dinoflagellates Euglenoids

Fungi Phycomycetes Ascomycetes Basidiomycetes

2. Kingdom Protista: Flagellates, dinoflagellates, ciliates, diatoms, sporozoans, etc.

• Mostly aquatic organisms.
• Mode of nutrition- parasitic, photosynthetic, ingestive, etc.
• Genetic material is an organized form.
• The endoplasmic reticulum, lysosomes, Golgi bodies, etc. Occurs.
• There is a double envelope system.
• Cell division occurs by mitosis.
• Flagella if present is 11- stranded. 
• Chrysophytes include diatoms and golden algae.
• Dinoflagellates are mostly marine and photosynthetic.
• Euglenoids are found in stagnant water.
• Slime moulds are saprophytic.
• Protozoans are heterotrophs.

3.Kingdom Fungi: Mildews, yeasts, mushrooms, bracket fungi, etc.

• Multicellular, spore-producing, eukaryotic organisms.
• Organisms are heterotrophic.
• The body of the fungus is filamentous called mycelium and filaments are called hyphae.
• Hyphae are multicellular and nuclei are small.
• The walls having chitin and noncellulosic polysaccharides.
• Reproduction is sexual and asexual.
• Glycogen and fat is food reserve.
• Phycomycetes are in aquatic habitats.
• Ascomycetes are saprophytic, decomposers, parasitic.
• Basidiomycetes are mushrooms, puffballs.
• Deuteromycetes are imperfect fungi. 

  

  Image 2: Fungi

  4. Kingdom Plantae: 
• Organisms are eukaryotic, multicellular, and indefinite growth.
• Nutrition is autotrophic.
• Photosynthetic activities are performed in plastids.
• Plants are fixed or free-floating.
• Starch and fat is food reserve.
• Heterotrophic plants are parasitic.
• Reproduction is sexual and asexual.
• Active locomotion is not found.

Image 3: Plants

  5. Kingdom Animalia: 

• Multicellular, eukaryotic, and with a regular body.
• An organ system is organized into different organisms.
• Response to stimuli is present.
• Photosynthetic pigments are absent.
• For mobility muscle cells are present.
• Reproduction is sexual.
• The embryo is formed.

Image 4: Animals

Virus:

• Nucleoprotein particle.
• Ultramicroscopic, obligatory parasite
• The capsid is an outer protective covering.
• Viruses are intermediate between living and non-living.
• Genetic material is either DNA or RNA  but no virus contains both.
• Plant viruses e.g., Tobacco Mosaic Virus, Potato Mosaic virus, Tomato leaf curl, etc.
• Animal virus e.g., Poliomyelitis virus, Influenza virus, Smallpox virus, Mumps virus, etc.
• Phagineae e.g., Bacteriophages, coliphages, cyanophages, phycophages, mycophages etc.
• Lysogenic Phase- viral genome gets integrate into the host DNA, the virus is non-virulent.
• Lytic Phase- viral genome does not integrate to the host DNA, virus is virulent.

Image 5: Virus

Viroid:

• RNA particle.
• The protein coat is not present.
• Small in size
• The low molecular weight of RNA

Lichens:

• Formed by fungus and algal called phycobiont.
• The relation is called mutualism.
• Algal provide food for fungus and fungus provide shelter.

Mycorrhiza:

• Association between fungus and root of the higher plant (pine).
• It is an example of mutualism.

Conclusion: Arranging of livings into the groups on the basis of affinities in the hierarchy of categories.

In this chapter, Biological Classification above the information is completed in detail with images.