Biology NCERT Text Books
NCERT (National Council of Educational Research and Training) has two Biology NCERT textbooks, one for class 11 & another for class 12. Both books have 5 units, with 22 chapters in the Class 11 textbook and 16 chapters in the Class 12 textbook, covering the 10+2 level higher secondary biology syllabus.
Today I am going to discuss my view about the biological concept behind the order of chapters in two books.
By definition, Biology is the study of ‘Life’ and the “Evolution of living organisms on Earth“.
Unit I: DIVERSITY IN THE LIVING WORLD
1st Chapter of Biology NCERT textbook, “The Living World” of this unit explains about life, the definition of a living organism & diversity of living organisms.
The main aim of biology is to scientifically study living organisms, which is next to impossible if the individual is not identified & classified into its convenient category. Chapter 2nd “Biological Classification” deals with that.
According to R.H Whittaker, an american Ecologist, based on Phylogeny Animal Kingdom comes after the Plant Kingdom. Similerly “Plant Kingdom” is described in chapter 3rd, after that, in chapter 4th, “Animal Kingdom” is described.
Unit II: STRUCTURAL ORGANISATION IN PLANTS AND ANIMALS
Till now, the Organism is defined, then identified & classified. To study the organism scientifically, we study the organism from the external body parts to the internal.
Firstly, we take a Plant as an organism. the external features of a plant body are studied in Morphology, which belongs to chapter 5 of the Biology NCERT textbook: “Morphology of Flowering Plants“.
Internal body part of a plant is to be studied at the tissue level in Anatomy, which is described in the next chapter, Chapter 6: “Anatomy of Flowering Plants“.
Then we take an Animal as an organism. In chapter 7 “Structural Organisation in Animals“, first Morphology, then Anatomy is described of Earthworm (Annelida), Cockroach (Arthropoda) and Frogs(Amphibia) on an evolutionary trend. Basic portion of HISTOLOGY under the topic “Animal Tissue” is illustrated at the beginning of this chapter.
Unit III: CELL: STRUCTURE AND FUNCTIONS
Now we are going into more detail in the body from the tissue level to the cellular level. In this unit chapter 8 “Cell: The Unit of Life” is about Cellular Structure & Function.
In more depths Celluler composition Biomolecules is explained in the next chapter, chapter number 9 ‘Biomolecules‘.
At the end, Cell Cycle and Cell Division: Mitosis, Meiosis goes to chapter 10 of the Biology NCERT textbook: “Cell Cycle and Cell Division“.
Unit IV: PLANT PHYSIOLOGY
The Physiological activity occurs at Celluler level. So the Biology NCERT text book discuss the Physiology after Cell Biology.
At first, Plant Physiology is divided into 5 chapters in Unit 4th.
Energy is the prime demand of all living organisms to be alive, which basically comes into an organism through food.
Plant as an ecologically producers (Autotrophs), they make their own food. Plants generally make food on it’s green part mainly leaves. To make food, Carbon dioxide and water are required. Leaves are trapped sunlight easily, Carbon dioxide is also available into air, diffuses to leaf directly. But the problem is arisen for water that comes from soil that is not directly touched by leaves. So a transport system is required to conduct Water and Minerals from the soil to the leaf. That’s why Plant Physiology starts with Chapter 11 of the Biology NCERT textbook: “Transport in Plants“.
Along with Water, Mineral is also transported from the soil, which has a vital role in Plant Nutrition. So in the next chapter, Mineral Element, Nutrient Cycle, etc. are described in Chapter 12: “Mineral Nutrition“.
Now the plant is ready for synthesis its own food (Glucose). the process is called Photosynthesis. It comes with chapter 13: “Photosynthesis in Higher Plants“.
Food is now going to each & every cell of the plant body to oxidise for getting Energy. The process of cellular oxidation and release of energy in the form of ATP is called Cellular Respiration, which is mentioned in the next chapter, Chapter 14 “Respiration in Plants“.
Finally, the plant is getting Energy which is to be used in Growth & develpoment of the Plant body. Plant Physiology ends with this topic in Chapter no 15, “Plant Growth and Development“.
Unit V: HUMAN PHYSIOLOGY
After Plant Physiology, 7 chapters of the Biology NCERT text book is covered for Human Physiology under the 5th unit.
Here we also apply the concept of energy.
Human as an animal is Ecologically Consumer (Heterotroph) means they can not make their own food. So a human body takes ready-made complex food and digests it into a simple form, then absorbs it. The whole process is explained under chapter 16, “Digestion and Absorption”, the first chapter of Human Physiology.
Now Oxygen is required to oxidise the food that is not produced in the human body. It comes from the air, outside the body, inhaled by the respiratory tract. its cover the chapter 17: “Breathing and Exchange of Gases“.
But it is impossible to reach the oxygen into all the cells of the body, Because Oxygen is transported through the respiratory tract only upto Lung. The circulatory system comes into effect, which circulate Respiratory gases, Nutrients, etc. throughout the body by Cardio-vasculer system. Chapter 18: “Body Fluid and Circulation“.
During oxidation of foods, Excretory products are also formed, being toxic it should be eliminated from the body. That’s why NCERT illustrated this in the chapter 19: “Excretory Products and their Elimination“.
Finally, energy is released from food particles, which is used to react to the physiological stimuli. As an animal, the human body responds to external stimuli by Movement and Locomotion. Chapter 20: “Locomotion and Movement” is talking about that.
The human body consists of several organs and the organ system [e.g, Digestive System, Circulatory System, etc.] covers more than one organ. So a Coordination must be required.
Short-term rapid coordination is established by the nervous system physically. Chapter 21, “Neural Control and Coordination” explains Physical Coordination.
Similarly, a special type of chemical called hormones coordinates and integrates the body parts chemically. Human Physiology is completed by this chapter 22: “Chemical Coordination and Integration“.
Unit VI: REPRODUCTION
An organism is fit for Reproduction when it is mature morphologically, anatomically, and physiologically. After studying all of that, we are going to know about Reproduction. Unit 6 of the Biology NCERT textbook (class 12) illustrates Reproduction into 4 chapters of the Biology NCERT textbook.
In the 1st chapter “Reproduction in Organism“, the methods and types of Reproduction is explained, then NCERT goes to specialisation for Plants in the 2nd “Sexual Reproduction in Flowering Plants“, and for humans, in the 3rd chapter “Human Reproduction” & 4th chapter “Reproductive Health” is illustrated respectively.
Unit VII: GENETICS AND EVOLUTION
Every species continue their generation through Reproduction, to know the theory of that, Unit 7 of Biology NCERT comes after Reproduction. In this unit, Chapter 5th and 6th is talking about Inheritance and Variation.
The variation may evolve the organism. That’s why Chapter 7 deals with “Evolution“.
From defining the organism to evolution, everything is studied till now; obviously, we gain biological knowledge which should be applied in Human Welfare. Units 8 and 9 of Biology NCERT give knowledge about that.
Unit VIII: BIOLOGY IN HUMAN WELFARE
In this unit, “Human Health and Disease” is discussed in chapter 8th, “Strategies for Enhancements in Food Production” in chapter 9 and “Microbes in Human Welfare” is explained in chapter 10 of class 12th Biology NCERT textbook.
Unit IX: BIOTECHNOLOGY
This unit has 2 chapters. Chapter 11 is about Principles and Processes of Biotechnology, and its application is given in Chapter 12.
Unit X: ECOLOGY
At last, after studying the organism, we are going to know about the interaction between the organism and its surroundings. It has 4 Chapters.
Chapter 13 is about “Organisms and Populations”.
Chapter 14 deals with ‘Ecosystem‘.
Chapter 15 is talking about “Biodiversity and Conservation“.
At the end, “Environmental Issue” is explained under chapter 16.
☆ Reference: Biology NCERT Text Book for Class 11th & 12th.