Important Notes on the Living World for NEET Biology

the Living World for NEET Biology

The living world is considered an important chapter for NEET. This chapter exposes you to the core principles of the universe of living beings; you must become acquainted with it. Additionally, having a good understanding of the topics taught in the chapter allows one to advance to far bigger concepts easily. Also, because this chapter is rather long, there's a good risk you'll miss several important points. However, by referring to these biological notes of the living world for NEET, one may swiftly reduce the stated risk. These notes will help you in your last-minute revision.

What Is The Living World?

Living things are made up of cells that can perform various cellular functions. Anything capable of growth, development, response, adaptability, and reproduction is considered living. These distinguishing traits help biology in determining whether or not something is alive.

Features of Living Organisms:

The following are the features of living organisms:

  • Cell division increases the number and mass of cells.
  • Tactile sense is the capacity to perceive the surroundings through touch.
  • Metabolism is a process in which the body's chemical makeup is formed and changed through biological processes.
  • Reproduction is the process of creating children and propagating them.
  • Cellular organization is one of the most distinguishing features of all living creatures.
  • Consciousness is the sensation of being aware of one's environment, activities, and goals.


Characteristics of Living Organisms

For your better understanding of the characteristics of living organisms, the following flow chart is shown:

  1. Growth
  2. Reproduction
  3. Metabolism
  4. Cellular Organisation
  5. Consciousness
  6. Interaction


  • Growth refers to the overall increase in mass or size of a tissue, organism, or components.

  • The twin features of growth are a rise in mass and an increase in number. This is a permanent and irreversible rise in the size of an organ, a component of it, or even a single cell.


There are two forms of growth:

  • Intrinsic growth: Growth that occurs within a live organism's body. This is the defining moment of one's life.

  • Extrinsic growth: Growth that occurs outside of the organism's body. As if it has accumulated on any part of the body. This form of growth is seen in non-living things.


There are two forms of intrinsic growth:

  • Indeterminate Growth: Unlimited growth is growth that continues continually over a long period. It can only be found in plants.

  • Determinate growth: Growth that happens only till a given age is reached. It is found in mammals. Only a few tissues have cell division to replace lost cells.



  •  It is the generation of a new person or offspring.

  • In the case of a multicellular organism is the development of progeny with characteristics that are more or less comparable to those of the parents.

  • In the case of unicellular organisms such as bacteria, unicellular algae, or amoeba, reproduction increases the number of cells. Growth and reproduction are synonyms or the same in unicellular organisms.

  • No non-living item can reproduce. Many living organisms, such as mules, infertile human couples, and worker bees, cannot reproduce. This is also not considered a distinguishing characteristic of life.


There are two modes of reproduction:

Asexual reproduction:

  • Asexual reproduction is a reproduction that does not entail fertilization, gametic fusion, or meiosis.
  • In algae and fungus, asexual spores are used.
  • In Yeast and Hydra through budding
  • In filamentous Algae, Fungi, and Protonema of moss plants via fragmentation.
  • By True Regeneration: Fragmented organisms restore missing body parts and transform into new organisms, such as Planaria.


Regeneration is a process in which only damaged body parts are healed or regenerated.

Sexual Reproduction:

Sexual reproduction is the process of forming gametes through meiosis and fertilizing them to produce children.

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Metabolism is the total of all chemical reactions that occur in our bodies. Metabolism is present in all organisms, including unicellular and multicellular. There are no non-living objects that display metabolic activity.

Cellular organization

The cell is life's fundamental unit. All creatures are made up of cells; some are made up of a single cell and are called unicellular organisms; others are made up of numerous cells and are referred to as multicellular organisms. Unicellular organisms are capable of autonomous existence and executing vital biological functions. Anything less than a cell structure does not guarantee autonomous life. All living organisms are made up of cells, the basic structural and functional units. This is life's distinguishing characteristic.


An organism can respond to external stimuli or changes in the environment. It is a characteristic of all living things. They can detect any changes in their surroundings.

If you are preparing for the NEET examination, you must have the living world NEET notes for your last minute revision. This will help you to boost your preparation.

Diversity in Living Organism

There are millions of plants and creatures in the living world. Biodiversity refers to the great variety of them and other living beings. The procedure of nomenclature is used to give each creature a scientific name. The names are widely accepted to minimize mistakes while referring to a species. Humans, for example, are known scientifically as Homo sapiens. The International Code for Botanical Nomenclature lays forth the agreed-upon principles for plants and creatures (ICBN). The International Code for Zoological Nomenclature, on the other hand, lays forth the agreed-upon principles for naming animals (ICZN).

The following are the specific terms based on which the bio diversities are classified:

  1. Nomenclature
  2. Classification
  3. Taxonomy
  4. Systematics

Taxonomy Categories

The classification process follows different steps that constitute a rank or category and are taxonomic categories. A taxonomic hierarchy is made up of these taxonomic groupings. Here are some key points to help you comprehend the hierarchy:

Species: A species is formed when organisms are grouped based on fundamental similarities.

Genus is a group of closely related species. Potato and brinjal, for example, belong to the same Solanum genus but are separate species. When comparing two genera, there are greater similarities than when comparing two species.

Family refers to a collection of closely related genera. Plant species' vegetative and reproductive characteristics are used to classify them into families. A family, in comparison to genera and species, has fewer similarities.

Order is a higher classification level than species, genera, and families. The aggregate of families is called order, indicating a lower amount of comparable characters.

Class is a group of orders that are connected.

Phylum/Division: Phylum is used in the case of animals, and Division is used in the case of plants to group together related groups.

Kingdom: the greatest level of the taxonomic system. This categorization is based on Taxon, which is observable characteristics.

Taxonomy Aids

Classification and identification are essential for the complete and accurate study of organisms. Biologists, researchers, and scientists will need to do laboratory and field research for this. Herbarium, museums, botanical gardens, and zoological parks are some frequent taxonomic aids.

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