NEET Study Notes for Diversity in Living World: Diversity in Living World is an essential part of NEET biology that will help you to understand the basic fundamentals of Biodiversity, Need for classification, Five kingdom classification and the classification of plants and animals. With a weightage of 9%, Diversity in the living world is one of the most essential topics in NEET Biology Syllabus and understanding it will help you fetch around 16 marks.

• Some of the essential topics include five kingdom classification, classification of plants and animals and their salient features.
• NEET Study notes for Diversity in Living World, will help you in understanding the concepts and practising sample questions can help you score well in NEET 2022.

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Important Topics in NEET Diversity in Living World

NEET Study Notes on Diversity in Living World

We can differentiate between non and living organisms based on the presence of certain characteristics. The characteristics of living organisms are:

• Metabolism
• Growth
• Reproduction
• Responsiveness
• Nutrition
• Respiration
• Movement
• Excretion
• Mortality
• Homeostasis

Diversity in Living World

Diversity refers to the total number and types of organisms found on earth. The common terms that are used for classification include:

Nomenclature- The term is used to give distinct scientific names to organisms for their identification. The names are of two types- generic( common name) and scientific names. When name with two components is provided, it is known as Binomial Nomenclature.

Systematics- The term is used to describe the interrelationship among plants or living organisms. Systematics ia also used to define morphological characters of plants or living organisms.

Taxonomy- Taxonomy is defined as the term for the process that is used to identify nomenclature and organisation of life forms by considering the inner and outer cell structure, advancement process, and biological data.

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Taxonomic Categories

There are 7 main Taxonomic categories. These are listed below in the hierarchical arrangement in ascending order

Kingdom

Division/Phylum

Class

Order

Family

Genus

Species

Taxonomic Aids

refer to techniques, information stored and procedures that aid in the identification and classification of entities. These are:

• Herbarium- Herbarium is used to store plant samples. These assembled plant samples are dried, squeezed and protected after which they are arranged as per the universally accepted classification system. A herbarium sheet consists of scientific name, date, where it was spotted, who collected it and other information relating to the same.
• Zoological Park- In a zoological part, wild animals with secure conditions are kept to observe their behavioural aspects and other traits of these animals.
• Botanical Gardens- Botanical Garden consists of living plant species that are accumulated and used as an information source.

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Types of Taxonomy

Taxonomy is classified into three different types:

• Alpha taxonomy- In Alpha taxonomy, only morphological characteristics are used for identification and classification of plants.
• Beta taxonomy- Beta taxonomy concerns with identifying based on genetical, anatomical, cytology, physiology and other characteristics.
• Omega Taxonomy- In omega taxonomy, analysis and synthesis of information is based on phylogenetic relationship.

Five Kingdom Classification

R.H. Whitewalker proposed the five-kingdom classification - Monera, Protista, Fungi, Plantae, and Animalia. This classification was made on the basic cell structure, mode of nutrition, phylogenetic relationship, and reproduction.

Kingdom Monera

All organisms present in Kingdom Monera are prokaryotes. The most important organisms of Kingdom Monera are Prokaryotes.

Characteristics of Kingdom Monera are;

• All the organisms are prokaryotes.
• Nucleus not bound by nuclear membrane
• Cell wall is present.
• Unicellular Organisms
• Reproduce asexually by binary fission or budding
• Cell wall is rigid and made peptidoglycan
• Movement is through flagella

Classification of Monera

Kingdom is classified into three sub-kingdoms =Archaebacteria, Eubacteria and Cyanobacteria. The salient features of these are provided below:

Archaebacteria

• The most ancient bacteria , found in the most extreme habits like salty area, hot springs and marshy areas are called Archaebacteria.
• Structure of Cell water is different from other bacteria.
• Mode of nutrition is autotrophic.

Eubacteria

• Eubacteria is also known as true bacteria.
• Movement is with the help of flagella.
• Eubacteria have a rigid cell wall.
• Examples of Eubacteria are known as Rhizobium and Clostridium.

Cyanobacteria

• Cyanobacteria are also known as blue-green algae.
• Found in aquatic region, these contain chlorophyll, carotenoids and phycobilins,
• Such bacteria are photosynthetic in nature.
• They are found in aquatic region.
• Examples of Cyanobacteria are Nostoc and Anabena.

Kingdom Protista

Kingdom Protista can be further divided into Chrysophytes, Dinoflagellates, Euglenoids, Slime moulds and Protozoans. The characteristics of Kingdom Protista are

• Unicellular Eukaryotic organisms
• They contain membrane bound organelles and nucleus
• Respiration is aerobic as well as anaerobic.
• Movement is by cilia and flagella.
• Reproduction is sexual as well as asexual.

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Kingdom Fungi

Characteristics of Kingdom Fungi are:

• They are non-motile and non-vascular.
• Unicellular and eukaryotic
• Reproduction is by spores called conidia or zoospores.
• Vegtative part of fungus is called mycelium.

Kingdom Plantae

Kingdom Plantae includes all photosynthetic, multicellular, and eukaryotic plants. Characteristics of Kingdom Plantae are:

• Mostly eukaryotic in nature.
• Existence of the main pigment is chlorophyll
• Cell walls are made up of cellulose.
• Reproduction can be sexual as well as asexual.
• Alternation of generation phenomenon is exhibited, that is diploid sporophyte and haploid gametophyte.

Kingdom Animalia

Characteristics of Kingdom Animalia are:

• Eukaryotic, heterotrophic, multicellular organism
• Well developed organ system such as skeleton system, circulatory and respiratory system.
• They have membrane-bound cells with nucleus which is bound by a nuclear membrane.
• Kingdom Animal have developed locomotory organs,

Viruses- Infectious agents that are active only inside the host organism are called viruses. Bacteriophages are those viruses that can infect bacteria. Other viruses can also infect plants and animals. The genetic material in virus is DNA or RNA.

Viroids- Small Infectious Agents that contain single-stranded DNA are called viroids. Viroids are small in size in comparison to viruses.

Lichens- These are symbionts between fungi and algae. Algae provides food for fungi and fungi produces provide shelter and absorb mineral nutrients and water for Algae.

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Classification of Plants

Natural system of classification is based on internal features. The type pf classification is provided below:

Algae

• Algae are autotrophic photosynthetic organisms.
• Algae belong to Thallophyta.
• Algae can be unicellular like Chlamydomonas, colonial like Volvox, or filamentous like Ulothrix.
• Reproduction in algae can be vegetative, sexual, and asexual.
• Vegetative reproduction occurs by fragmentation. Each fragment gives rise to Thallus.
• Asexual Reproduction occurs through Zoospores, these can be flagellated or non flagellated. These spores on germination give rise to new plants.

Bryophytes

• Bryophytes include mosses and liverworts.
• These are also known as amphibians of the plant kingdom. Because they exist in soil but depend on water for sexual reproduction.
• They contain a hairy-like structure is known as Rhizoids, they help in absorption and fixation.
• Reproductive Organs in Bryophytes are multicellular. Male sex organ is known as antheridium. They produce male gametes known as antherozoids. Female sex organs are called archegonium,, it is flask-shaped and produces egg.
• The fertilization of antherozoids and egg form zygote. Zygotes produce a multicellular body called the sporophyte.

Pteridophytes

• Pteridophytes are also called vascular cryptogams as they possess xylem and phloem
• Pteridophytes do not produce flowers or seeds. They possess roots and leaves.
• In pteridophytes, small leaves are known as microphyll, whereas large leaves are called macrophylls.
• Leaves that contain sporangia are called sporophyll. Sometimes a compact structure is formed, known as strobili or cones.
• On germination, spores form prothallus
• The spores that are formed can be spores of similar kind or homosporous and spores of different kind or heterosporous. Spurs found in the majority of pteridophytes are homosporous. Heterosporous spores are found in Selaginella and Salvinia. Examples of Pteridophytes are horsetails and ferns.

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Gymnosperms

• Gymnospersms act as a link between pteridophytes and angiosperms.
• They are seed producing , non flowering plants.
• All Gymnosperms are perennial and include medium sized trees or tall trees and shrubs.
• In Gymnospersms, needle like leaves to reduce the surface area. An example is Conifers.
• The spores are heterosporous, Female spores are known as megaspores whereas the male spores are called microspores. Megaspores are formed in megasporangia. Microscopes are formed in microsporangia.
• Male and female gametophytes depend on each other with sporangia. Megasporagium mature into archegonia.
• Pollen Tube carry male gametes towards archegonia. Then fertilization occurs between male gamete and female gamete. The formed zygote develops into an embryo and the ovule develops into seeds.

Angiosperms

• These are flower-producing plants that have seeds enclosed within the seed coat. Within the fruit, seeds are enclosed. Angiosperms are divided into monocots and dicots. Dicots contain two cotyledons while monocots contain one cotyledon.
• The male reproductive organs is called stamen. Stamen consists of anther and filament. Anther produces male gametes that are known a pollen grains.
• Female reproductive organ is called pistil or carpel. Pistils consist of three parts- stigma, style and ovary.
• Pollen lands on the stigma during pollination. Ovary contains ovules. Embryo Sacs are reduced female gametophytes that are present within ovules.

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Classification of Animals

Porifera (Sponges)

• They are symmetrical, marine with organisation of cellular level.
• Water transport system helps in food intake, gaseous exchange and excretion.
• Reproduction sexual and asexual. Sexual is through formation of gametes and asexual is through fragmentation.
• Examples are Spongilia, Eispongia and Sycon

Coelenterata

• Coelenterata are aquatic with tissue level of organization, diploblastic, and symmetrical radially.
• A single opening called hypostome is present in the central gastrovascular activity. These are surrounded by sensory testacles.
• Digestion in Coelenterata can be extracellular and intracellular.
• Examples - Meandrina( Brain Coral), Adamsia (Sea Anemone), Gorgonia (Sea Fan).

Ctenophora

• Also known as sea walnuts or comb jelly.
• Externally, eight rows of ciliated combs are present.
• Fertilization occurs externally with indirect development.
• Ctenaphores are hermaphroditic.
• Examples - Ctenoplana, Pieurorbrachia

Platyhelminthes

• Platyhelminthes also known as flatworms, are mostly endoparasites with dorsoventrally flattened body and organ level organization.
• Osmoregulation and excretion occur due to the presence of flame cells.
• Through many larval stages, indirect fertilization and indirect development occurs..
• Example- Fasciola (Liver Fluke), Taenia (Tapeworm)

Ascelminthes

• Ascelminthes are free-living or parasitic in nature, living in aquatic or terrestrial land.
• Internal Fertilization occurs with direct or indirect development.
• Alimentary canal has a muscular pharynx and is complete.
• Examples- Ascaris (Roundworm), Wuchereria (Filarial Worm)

Annelida

• Annelida are bilaterally symmetrical with organ system organization.
• Locomotion is aided by Longitudinal and circular muscles.
• Examples - Pheretima (earthworm), Hirudinaria( bloodsucking leech)

Arthopoda

• Arthropoda is the largest species with about 9,00,000 species.
• They are bilateral triploblastic with organ system level of organization.
• These contain insects, due to jointed appendages, it derives the name arthropods where anthro means joints and poda is the foot.
• Their body wall consists of thick chitinous cuticle.
• They have Malpighian tubes for excretion
• Examples- Bombyx (Silkworm), Apis (Honey bee)

Mollusca

• Mollusca is the second largest Phylum
• Their body is usually bilateral. Snail is asymmetrical due to torsion during growth. These are triploblastic with organ system organisation.
• Feather-like gills enable functions of respiration and excretion.
• There are three body regions which include head, visceral mass, and foot.
• Examples- Pila (apple snail), Octopus (devilfish), Pinctada (pearl oyster).

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Echinodermata

• Echinoderms are triploblastic with organ system level organisation.
• They have bilateral symmetry in larva and radial symmetry in adults.
• Presence of water vascular system aids in locomotion.
• Example- Asterias (starfish), Echinus (sea urchin)

Chordata

• Chordata is derived from, Chor which means thick string and ata which means to have. This name comes due to the presence of notochord.
• The main features of the Chordata are the notochord, dorsal tubular nerve chord, and pharyngeal gills.

NEET Sample MCQs for Diversity in Living World

Question: How does regulation of activities of cells take place?

1. Flow of energy
2. Flow of substances
3. Flow of Energy
4. Flow of smoke

Answer: Flow of Energy

Question: What is the correct sequence of taxonomic categories?

1. Species > Genus > Order > Phyllum
2. Genus > Species > Order > Kingdom
3. Species > Order > Genus > Kingdom
4. None of the above

Answer: Species > Genus > Order > Phyllum

Question: What is the first step in taxonomy/

1. Classification
2. Description
3. Naming
4. Identification

Answer: Identification

Question: What does ICBN stand for?

1. International Code of Botanical Nomenclature
2. International Congress of Biological Names
3. International Code of Botanical Nomenclature
4. Indian Congress of Biological Names

Answer: International Code of Botanical Nomenclature

Question: In which of the following reproductive organs are hidden?

1. Cryptogamae
2. Angiosperms
3. Gymnosperms
4. Phanerogamae

Answer: Cryptogamae

Question: What is the meaning of Arthropod?

1. Jointed legs
2. Largest legs
3. Cartilaginous legs
4. Bonous legs

Answer Jointed Legs

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