Biological Classification: Kingdoms, Categories, and Question

Biological Classification: Overview, Topics, Five Kingdoms, Books, Tips, Questions

Edited By Irshad Anwar | Updated on Oct 24, 2024 05:10 PM IST

Biologic classification or biologic taxonomy is the orderly process by which living organisms are grouped into categories in terms of shared characteristics and evolutionary relationships. It's significant for the field of biology and enables scientists and students to explore the grand diversity of life. This chapter is a part of the Class 11 Biology syllabus and is important for students preparing for competitive exams like NEET. This article comprises all aspects of biological classification from 5 kingdom classification to the animal kingdom classification to the plant kingdom classification.

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Overview of the Chapter
Important Topics of Biological Classification
What is Biological Classification?
The 5 Kingdom Classification System in Biology
Kingdom Monera
Kingdom Protista
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia
Human Biological Classification
Tips, Tricks, and Strategies for Preparing Biological Classification
Prescribed Books for Biological Classification
Types of Questions Asked on Biological Classification in Exams
Recommended Video on Biological Classification

Biological Classification: Overview, Topics, Five Kingdoms, Books, Tips, Questions

Overview of the Chapter

The Chapter Biological Classification introduces a systematic classification of living organisms displaying similarities and dissimilarities. Different modes of classification are discussed, keeping much emphasis on R.H. Whittaker's five-kingdom classification- namely Monera, Protista, Fungi, Plantae, and Animalia. Characteristics like nutrition, and mode of reproduction in each kingdom are explained. Viruses, viroids, and lichens are also studied for their biological importance. The chapter also explains the basic knowledge about biodiversity and the evolutionary relationships among organisms.

Important Topics of Biological Classification

Five Kingdom Classification
Kingdom Monera, Protista and Fungi
Plantae, Animalia and Viruses
Important concepts - taxonomy, Nomenclature, basis of classification

What is Biological Classification?

Biological classification is scientifically defined as the science of categorising living things into hierarchical groups on the basis of similarities and their evolutionary history. It helps in the proper classification and prediction of characteristic features among the species, which makes it easier for biologists to study and identify living things.

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Biological Taxonomy and Importance

Biological taxonomy is the specific part of biology, which deals with all classifications, nomenclature, and identification of organisms. Thus, biological taxonomy follows a well-defined hierarchy, which includes:

Kingdom
Phylum
Class
Order
Family
Genus
Species

Taxonomy serves to offer an international language amongst scientists. Hence, every organism boasts of a universally accepted and standard name by the use of binomial nomenclature. The study of biological taxonomy is crucial for biology class 11 biological classification and provides a base for more advanced concepts in biology.

The 5 Kingdom Classification System in Biology

The 5 kingdom classification system was developed by Robert Whittaker back in 1969. It categorizes all the living organisms into five different kingdoms:

Monera: These are unicellular prokaryotes, such as bacteria, having no nucleus and membrane-bound organelle.
Protista: Mostly unicellular eukaryotes, such as algae, protozoans, and slime moulds.
Fungi: These are the eukaryotic organisms that absorb nutrients from organic matter, and examples include moulds, yeasts, and mushrooms.
Plantae: These are multicellular autotrophs that perform photosynthesis. They include mosses, ferns, gymnosperms, and angiosperms.
Animalia: These are multicellular heterotrophs that obtain their food by ingesting others. They range from simple sponges to complex mammals.

Biological Classification in Class 11 Biology

Biological Classification forms a major chapter in the NCERT syllabus of biology class 11 for students. It introduces the classification of living things according to their morphological and genetic features. The chapter is really important for both CBSE Board Exams and entrance exams like NEET.

Kingdom Monera

Bacteria are classified as members of the Monera Kingdom.

Characteristics of Monerans

They have the following crucial characteristics:

Bacteria are minute organisms that can be found almost anywhere.
They are prokaryotic and have a cell wall.
Amino acids and carbohydrates make up the cell wall.
Bacteria can grow in both heterotrophic and autotrophic environments.
The bacteria that live in heterotrophic environments might be parasitic or saprophytic. Chemosynthetic or photosynthetic autotrophic microorganisms are both possible.

Living World and Classification of Microbes

Half of the living world is microorganisms, that is, bacteria, fungi, and viruses. Classification of microbes in the living world is done on the basis of their shape, such as cocci and bacilli, and metabolic activity.

Bacterial Taxonomy

Bacterial Taxonomy Bacterial taxonomy classifies bacteria into different categories based on their characteristics. A study of such classification would enable an understanding of diversity in bacteria. Such classification also helps one understand several diverse roles bacteria play in different ecosystems.

Monerans Bacteria are divided into four categories based on their shape:

Shape	Bacteria Type	Example
Cocci	spherical shaped	Staphylococcus aureus
Bacilli	Rod-shaped	Escherichia coli
Spirilla	Spiral-shaped	Helicobacter pylori
Vibrium	Comma-shaped	Vibrio vulnificus

Kingdom Protista

Protista Characteristics:

The following are some of the most important characteristics of Protista:

They are eukaryotic and unicellular creatures.
For mobility, some of them contain cilia or flagella.
Cell fusion and zygote formation are used in sexual reproduction.

Kingdom Protista Classification

Protista is divided into the following groups:

Chrysophytes: This group includes golden algae (desmids) and diatoms. They live in both marine and freshwater environments.
Dinoflagellates: They are often photosynthetic and saltwater organisms. Their colour is determined by the major pigments in their cells, which might be red, blue, brown, green, or yellow.
Euglenoids: The majority of Euglenoids reside in freshwater habitats in still water. They lack a cell wall and instead have a protein-rich layer termed a pellicle.
Slime Moulds: Saprophytic slime moulds. The body glides along with decomposing leaves and twigs, feeding on organic matter. They form a clump in favourable conditions and are referred to as Plasmodial.
Protozoans: Protozoans are heterotrophic organisms that can live as parasites or predators.

Kingdom Fungi

Molds, mushrooms, yeast, and other fungi are all members of the fungi kingdom. They have a wide range of uses in both household and commercial settings.

Fungi Kingdom Characteristics

The fungi, with the exception of yeast, are filamentous (single-celled).
Hyphae are slender, long thread-like structures that make up their form. Mycelium refers to the web of hyphae.
Unbroken tubes jam-packed with multinucleated cytoplasm make up some of the hyphae. Coenocytic hyphae is the name given to such hyphae.
The other form of hyphae is septae or cross-walls.
Polysaccharides and chitin make up the cell wall of fungi.
The majority of the fungi are heterotrophic saprophytes.
Some fungi live as symbionts with other organisms. Some of them are parasitic. Some symbiotic fungi, such as lichens, exist in association with algae. As mycorrhiza, some symbiotic fungi live in connection with the roots of higher plants.

NCERT Notes Subject Wise Link:

Classification of Animal and Plant Kingdoms

A proper understanding of the diversity of life requires the classification of animal and plant kingdoms. While the classification of animals is based on the structure of a body, level of symmetry, and organ systems, the classification of plants is primarily based on the types of reproductive structures and methods used for photosynthesis.

Kingdom Plantae

Features of Kingdom Plantae:

All eukaryotes having chloroplasts belong to the kingdom Plantae.
The majority of them are autotrophic, although some are also heterotrophic.
Cellulose makes up the majority of the cell wall.
Plants go through two stages in their life cycle. The saprophytic phase is diploid, and the gametophytic phase is haploid.
The lengths of the diploid and haploid phases differ between different plant families. This process is known as the Alternation of Generation.

Biological Classification of Plants

The biological classification of plants divides them into groups on whether the plants may reproduce seeds, vascular tissues, and reproductive parts. The major plant types are as follows:

Bryophytes: Unable to form a vascular system; mosses and other related plants.
Pteridophytes: These are seedless vascular plants, such as ferns.
Gymnosperms: These plants produce seeds but do not have flowers, such as conifers.
Angiosperms: Flowering plants; seeds enclosed in fruits.

In many ways, understanding the structure and classification of a plant kingdom can be very necessary for an understanding of the classification of living things as it is in biology.

Kingdom Animalia

Animalia's Characteristics:

This kingdom encompasses all heterotrophic multicellular eukaryotes that lack a cell wall.
Plants provide nourishment to animals either directly or indirectly. Their feeding mode is holozoic. Holozoic feeding entails ingesting food and subsequently digesting it with the aid of an internal cavity.
Many of the animals are capable of moving about.
They reproduce through sexual reproduction.

Animal Kingdom Biology

The animal kingdom is a broad group of organisms, ranging from simpler invertebrates to more complex vertebrates.

Porifera: It is one of the major phyla, which includes sponges-the simplest multicellular animals.
Cnidaria: jellyfish with radial symmetry.
Arthropoda: Insects, arachnids, and crustaceans. These creatures have segmented bodies; they also have exoskeletons, which protect their bodies.
Chordata: Animals having a notochord. They are categorised into classes including fish, amphibia, reptilia, aves and mammals.

NCERT Solutions Subject wise link:

Human Biological Classification

Humans belong to the Animalia kingdom of the following biological taxonomy:

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: Homo sapiens

The biological classification of humans reflects our evolutionary history and relationship with other organisms in the animal kingdom.

Tips, Tricks, and Strategies for Preparing Biological Classification

Given below are some tips and tricks to prepare for biological classification:

Mnemonics

The mnemonic to use in referring to the hierarchy of biological classification is: King Philip Came Over For Good Soup (Kingdom, Phylum, Class, Order, Family, Genus, Species)

Study Aids

Create charts or tables to illustrate the five-kingdom classification.
Create diagrams of various types of kingdoms, and focus very much on animal and plant cell differentiation.

Multimedia

Watch animations or videos about the five-kingdom classification and characteristic differentiations.

Flashcards

Use flashcards to help you memorize the characteristics of different kingdoms and taxa.

NCERT Exemplar Solutions Subject wise link:

Prescribed Books for Biological Classification

NCERT Biology textbook class 11 forms the base for learning about biological classification. Further extended understanding of the concept can be done through "Trueman's Elementary Biology, Volume 2", which provides all essential explanations with practice questions. Another helpful book is "Pradeep's Biology" which provides proper explanations with solved examples. Other great videos, articles, and practice mock tests are available on the Careers360 website for this chapter.

Ncert Books Link:

Types of Questions Asked on Biological Classification in Exams

The types of questions related to biological classification asked in various exams are as follows:

Exam Type	Types of Questions	Weightage
CBSE	Definitions, classification criteria, short answers on kingdom characteristics, examples	4-5%
NEET	MCQs on 5-kingdom classification, key features of organisms, bacterial taxonomy	3-4%
AIIMS	Assertion and reason-based questions on classification and evolutionary relationships	1-2%
Nursing Entrance Exams	Scenario-based questions, case studies on microorganisms and classification	2-4%
Paramedical Exams	True/False on classification, functions of microbes, plant and animal kingdoms	1-3%

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Fungus Life Cycle	Classification of Virus
Angiosperm and Gymnosperm Difference	Phylum Platyhelminthes
Phylum Ctenophora	Phylum Mollusca
Urochordata	Cephalochordata