Biology - Definition, Branches, Example, Concepts, & History (Updated)
Biology is the study of life, from tiny cells to vast ecosystems. It explores how organisms grow, function, and evolve. This guide covers definitions, branches, examples, diagrams, and NEET-ready MCQs.
Biology is a broad and diverse field that includes many subdisciplines, including molecular biology, cell biology, anatomy and physiology, animal behavior, population biology, ecology, systematics, microbiology, virology, botany, and zoology and deals with all the physicochemical aspects of life. It also explains the cellular and bacterial forms of life. New technology has helped us understand more about living things. For example, when scientists discovered viruses, it made them think about what it means to be alive.
- What is Biology?
- Importance of Biology
- Branches of Biology
- Example of Biology in Action
- Important Concepts in Biology (Class 11 & 12)
- History of Biology
- Biology NEET MCQs
- Biology Concept Videos (Watch & Learn)
What is Biology?
The term "biology" is derived from the Greek words "bios," meaning life, and "logos," meaning study or science. Biology is defined as the study of the living world, their origins, anatomy, morphology, physiology, behaviours, evolution, and distribution. The subject also includes how they interact with their environment and other organisms. Aristotle is known as the father of biology. Modern biology explains the more complex forms and systems that support life. Biology is a constantly changing science; new developments, including genetic engineering and synthetic biology- change our notions of what life is and will be.
Importance of Biology
As a field of science, biology helps us understand the living world and the ways its numerous species function, evolve and interact. Advances in medicine, agriculture, biotechnology, and many other areas of biology have brought improvements in the quality of life. Fields such as genetics and evolution give insight into the past and can help shape the future, and research in ecology and conservation informs how we can protect the precious biodiversity of this planet.
Branches of Biology
The study of biology includes several branches of biology that have different dimensions of life and often relate to other scientific streams. For example, Systematic Biology focuses on complex interactions within biological systems. Using both computational and experimental approaches, it explains how networks of genes, proteins, and other cellular components interact to perform functions with each other.
Some of the other important divisions within biology studies are:
The entire study of biology, therefore, has been divided into several divisions of biology to study the details of specific aspects of life. Some of the branches of biology have further combined with other subjects like chemistry and physics and resulted in the discovery of new fields of study.
Anatomy
Anatomy is the branch of biology that deals with the study of structure and organisation in living organisms. It includes the study of humans, plants, and animals concerning the internal and external features related to other body parts or systems.
Molecular Biology
Molecular Biology deals with the molecular basis of biological activity. It describes in detail DNA, RNA, and proteins, and how these molecules regulate cell functions.
Genetics
The study of heredity and variation is known as genetics. It explains how traits are inherited from one generation to another through genes. The two important fields of genetics are classical genetics, dealing with Mendelian inheritance and molecular genetics, studying genes at the DNA level.
Biotechnology
This branch applies biological systems and organisms to develop or alter products for use by humans. Examples of such recent biotechnology inventions include genetic engineering, cloning, and the use of CRISPR technology.
Microbiology
Microbiology is the study of microorganisms, including bacteria, viruses, and fungi. The discipline is important in understanding diseases, antibiotics, and microbes' ecological roles.
Zoology
The course of zoology covers the study of animal behaviour, physiology, and classification. Subjects ranging from minute insects to large mammals are taken up for study by zoologists.
Botany
Botany deals with life in plants that is growth, reproduction, metabolism, and disease. For life to exist on Earth, it needs plants to provide oxygen, food, and a habitat.
Ecology
Ecology deals with the study of the relationship between living organisms and their environment, that is ecosystems, biodiversity, and conservation.
Immunology
Immunology deals with the study of the immune system, mainly how the body protects itself from the pathogenic attacks of viruses and bacteria. It includes the mechanism of immune responses and the role of antibodies in protecting the body from infections.
Physiology
It studies the functioning of living organisms and their systems, and how organs, tissues, and cells work together to provide life. It includes processes like respiration, blood circulation, and digestion and absorption, which regulate body functions and its response to the environment.
Example of Biology in Action
The "biology" definition explains living organisms, and examples show how these organisms grow, work and interact with their environment. For example:
Photosynthesis: The biological process in which plants convert sunlight into chemical energy.
Ecosystem: Relationship between living organisms as well as their environment including food webs and nutrient cycles
Cell division: Mitosis and meiosis are examples of how cells divide and pass on the genetic information
Evolution: The process by which species evolve based on selection over many generations.
DNA Replication: It is the biological process of creating two identical replicas of DNA from one original DNA molecule.
Human Anatomy: The study of the human body and its system
Immune Response: How the body protects itself against disease and pathogens
Neuroscience: The study of the nervous system, especially concerning the brain and how it controls body functions.
Important Concepts in Biology (Class 11 & 12)
Below are the most important and basic concepts of biology. These concepts are included in the biology NCERT and students can also get biology notes easily on these concepts:
Carbon Properties & Cycle
Carbon is a very versatile element, it makes the basic framework of organic molecules. Due to the special properties of its electronic structure, carbon can exist in all three important types of chain bonds-simple, double, and triple-along with rings and complex ring systems that are necessary for living systems.
Human Biology Systems
Human biology studies the structure, function, and processes of the human body. The circulatory, respiratory, and nervous systems along with many other systems keep the individual healthy and in homeostasis.
Macromolecules
Large biological molecules are defined as macromolecules. Examples include proteins, carbohydrates, lipids, and nucleic acids. They are highly important molecules for cell structure, storage of energy, and passage of genetic information.
Energy and Enzymes
The energy within living systems is largely derived from chemical reactions. The substances that accelerate chemical reactions are known as catalysts and, in living organisms, enzymes. Enzymes would lower the activation energy for all sorts of life processes, which include metabolism and digestion.
Structure of a Cell & Membranes
A cell is the smallest unit of life. Organelles which constitute the cell include the nucleus, mitochondria, and endoplasmic reticulum. These organelles interact in carrying out vital functions of the cell that include energy production, synthesis of proteins, and waste removal, among others. Cell Biology topic is covered in class 11 biology.
Cellular Respiration
Cellular respiration is the process through which cells use glucose and oxygen to form ATP, the energy currency of the cell. It involves changes in glycolysis, the Krebs cycle, and the electron transport chain, releasing energy to fuel cellular activities.
Photosynthesis
Light energy is transformed into chemical energy by photosynthesis in plants, algae, and some bacteria, producing glucose and oxygen. It occurs in the chloroplasts and is of immense importance regarding the flow of energy within ecosystems.
Cell Division
Cell division involves mitosis and meiosis, processes in which cells form other cells. Mitosis produces genetically identical cells for growth and repair, while meiosis generates genetically diverse gametes for sexual reproduction.
Genetics & DNA
Classical genetics studies the study of inheritance patterns. This is mainly based on Mendel's laws of inheritance. Molecular genetics involves the study of genes at a molecular level that includes a great emphasis on DNA, RNA, and the synthesis of proteins.
DNA stands for deoxyribonucleic acid. It is the very molecule that contains genetic information stored in living organisms. DNA dictates cellular processes by coding for proteins and, upon its replication, ensures that genetic information is passed on to offspring.
Central Dogma
The central dogma of molecular biology is the movement of genetic material from DNA to RNA to protein. It gives information about how DNA transcribes mRNA by translating into proteins that carry on different cellular functions.
Gene Regulation
Gene regulation is a control function that allows the cells to express genes properly at required times and in adequate amounts, ensuring the proper production of proteins. It is important in both cell differentiation and cell development and in the ability of the cell to respond to environmental changes.
Biotechnology Basics
The use of biological agents to develop goods and technologies that improve human lives is studied under this topic. This involves the use of genetic engineering, cloning, and medicine and biofuel development.
Microorganisms
Bacteria and Archaea
Bacteria and archaea are kinds of prokaryotic microorganisms. Bacteria exist in several different ecological environments, archaeons tend to be in extreme environmental conditions. Both organisms have greater ecological roles in nutrient cycling and biotechnology.
Viruses
A virus is a small infectious agent that requires a living host cell for replication. It possesses genetic material, DNA or RNA, enclosed in protein. Viruses infect all life forms-from bacteria to humans-causing diseases.
Evolution
Evolution is the gradual modification of species in such a way that life becomes diverse. It is driven by natural selection, mutation, and genetic drift. The Tree of Life maps the relationships among organisms, providing a visible guide to their evolutionary history.
Ecology
Ecology is the interaction of living organisms among themselves and with their environment. It includes ecosystems, population dynamics, food chains, and the impact of human activity on natural habitats.
Biodiversity and Conservation
Biodiversity refers to the variety in life on Earth which includes species diversity, ecosystem diversity, and genetic diversity. Biodiversity and conservation includes In situ and Ex situ conservation
Plant Biology
It includes the structure, function, growth, and reproduction of plants. The process of photosynthesis, transpiration and the ecological role of primary producers are studied under this topic.
History of Biology
Biology as a science is deeply rooted in history and evolved significantly over time.Before the term biology was adopted, disciplines such as Natural History defined the study of plants, animals and fungi in their natural environments, and those who studied it were called natural historians or naturalists. Other disciplines also include Natural Theology and Natural Philosophy.
The word "Biology" was coined by Michael Christoph Hanow in 1766 and independently by Thomas Beddoes, in 1799, Karl Friedrich Burdach, in 1800, Gottfried Reinhold Treviranus, in 1802 and Jean-Baptiste Lamarck, in 1802.
Major Scientists & Their Discoveries
The early human beings survived by knowledge of plants and animals, which was passed from generation to generation. More significant steps in Biology came with the transition from hunting and gathering into farming, furthering knowledge of agriculture and animal domestication. Biology as a branch came into shape from early contributions by Aristotle. It was significantly developed during the 19th century with various discoveries and experiments.
Given below is the list of major scientists and their contributions which formed a base for the understanding of various concepts in Biology:
Scientist | Title/Contribution | Discovery/Explanation |
Aristotle | Father of Biology | Classified organisms as plants and animals, proposed scala naturae, also known as the Great Chain of Being and conducted studies on animal anatomy and reproduction. |
Hippocrates | Father of Medicine | Founded human anatomy and physiology through the Hippocratic Corpus; established medicine as a unique science separate from philosophy and superstition. |
Theophrastus | Father of Botany | Wrote Historia Plantarum, which began studies on botany dealing with the classification of plants, plant growth, and plant reproduction. |
Galen | Early Medical Pioneer | Contributed to anatomy and physiology, including studies on the circulatory system, bones, muscles, and nerves derived from animal dissections. |
Andreas Vesalius | Father of Modern Anatomy | Conducted human skin dissections; corrected many of Galen's anatomical mistakes; wrote De Humani Corporis Fabrica. |
William Harvey | Pioneer of Cardiovascular Physiology | The first one to describe the blood circulation pumped by the heart; his book De Motu Cordis is considered the foundation of circulatory physiology. |
Anton van Leeuwenhoek | Father of Microbiology | First to view microorganisms (bacteria, protozoa) with the help of homemade microscopes and allowed microbiology and cell theory to begin. |
Robert Hooke | First to Identify Cells | Came up with the term "cell" after observation of cork structure under the microscope; published findings in Micrographia. |
Carl Linnaeus | Father of Taxonomy | Binomial nomenclature-Systema Naturae: provided the uniform system for naming and classification of species. |
Jean-Baptiste Lamarck | Early Evolution Theorist | Lamarckism or the proposal that organisms acquire traits in their lifetime and pass it on to the offspring was also given by him, though the same was proved wrong. |
Matthias Schleiden & Theodor Schwann | Founders of Cell Theory | Co-proposed the theory that states that all living organisms are made up of cells and are the basic units of life. |
Martinus Beijerinck | Father of Virology | In his study on TMV, the highly infectious tobacco mosaic virus, he discovered viruses as infectious agents much smaller than bacteria. |
Biology NEET MCQs
Q1. Omnis cellula e cellula is the concept of ______ given by_____
Cell division; Rudolf Virchow
Cell respiration; Meredith Grey
Cell death; Harper Avery
Cell maturation; Leeuwenhoek
Correct answer: 1) Cell division; Rudolf Virchow
Explanation:
In 1838, German botanist Matthias Schleiden observed that all plants are composed of cells, and in 1839, German zoologist Theodor Schwann extended this idea to animals, declaring that they too are made up of cells. These foundational observations led to the formulation of the Cell Theory, which was later refined by German physician Rudolf Virchow, who introduced the famous dictum Omnis cellula e cellula ("new cells arise from pre-existing cells"). The Cell Theory states: (1) All living organisms are made up of one or more cells, (2) Cells are the basic unit of structure and function in organisms, and (3) New cells arise only from pre-existing cells, as they are self-reproducing. This theory remains a cornerstone of modern biology.
Hence the correct answer is option 1) Cell division; Rudolf Virchow
Q2. Which of the following statements is incorrect?
The major components of our food are carbohydrates, proteins and fats.
The major components of our food are carbohydrates, proteins and fats.
Food is reduced in the presence of oxygen to release energy in a process called aerobic respiration.
Food provides energy and organic materials for the growth and repair of tissues.
Correct answer: 3) Food is reduced in the presence of oxygen to release energy in a process called aerobic respiration.
Explanation:
Food is oxidized in the presence of oxygen to release energy in a process called aerobic respiration. Food (usually glucose) is oxidized not decreased during aerobic respiration. Energy is released during the process when glucose (or other organic molecules) oxidizes in the presence of oxygen. The energy currency of cells- ATP (adenosine triphosphate) is created using this energy.
Hence, the correct answer is option 3) Food is reduced in the presence of oxygen to release energy in a process called aerobic respiration.
Q3. In E.coli, the lac operon gets switched on when:
Lactose is present, and it binds to the repressor
Repressor binds to operator
RNA polymerase binds to the operator
lactose is present, and it binds to RNA polymerase
Correct answer: 1) lactose is present, and it binds to the repressor
Explanation:
Lactose metabolism involves the regulation of gene expression that is determined by the presence or absence of the lac operon in bacteria. Here is how it works:
Lactose Binding: Once lactose exists in the surrounding environment, then it will bind to the attached repressor protein along the operator region of the lac operon.
Repressor Inactivation: This binding leads to a conformational shift of the repressor, which can't bind to the operator anymore. RNA polymerase is thus able to access the promoter region of the operon.
Gene Expression: The genes for lactose metabolism-the lacZ, lacY, and lacA-are transcribed. In this manner, bacteria can use lactose as an energy source.
It presents an example of inducible gene expression - the presence of lactose substrate allows for increased expressions of genes concerning its metabolism.
Hence the correct answer is Option (1) lactose is present, and it binds to the repressor.
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Biology Concept Videos (Watch & Learn)
These selected videos will help you understand process of photosynthesis and evolution in a more engaging and visual way — perfect for quick revision.
Basics of Photosynthesis:
- This video describes the basics of photosynthesis which forms the base of the food chain, supporting life on Earth.
- It will help students understand the pathway of energy in an ecosystem, the role of plants in oxygen production, and the importance of sustainable agriculture and food security.
Biological Evolution:
- The video given below on Biological evolution describes the process through which species of organisms change over generations through variations in their genetic material.
- Students will get more clarity on the development of new species and adaptations to changing environments from this video.
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Frequently Asked Questions (FAQs)
Biology is the science that deals with studies about life and living organisms, their structure, function, growth, evolution, distribution, taxonomy, methodology of study, and their interaction with the environment.
Biology has helped us understand the natural world, human health, environmental issues, and interdependencies of life forms. It assists in the furtherance of medicine, agriculture, and biotechnology.
Some major divisions or branches of biology include the botany-study of plants, zoology-study of animals, microbiology-study of microorganisms, genetics, and ecology.
The term "biology" was independently derived by several scientists like Michael Christoph Hanow and Jean-Baptiste Lamarck in the late 18th and early 19th centuries.
There is some overlap between biology and chemistry, physics, and mathematics in the fields of biochemistry, biophysics, and theoretical biology that explain life from the molecular and physical perspective.
Aristotle is also made famous and has been attributed as the "Father of Biology" simply because of the broad studies he conducted and the classification he did on all living organisms from animals to plants.
Maria Sibylla Merian is known as the "Mother of Biology" because she did the fundamental work in the field of entomology and took the records of the life cycles of insects.
Aristotle is known as the "Father of Zoology" because he laid down the very foundation of animal behavioural study, anatomy, and classification.
Martinus Beijerinck is considered the "Father of Virology" because he discovered viruses as infectious agents, especially through his work on the tobacco mosaic virus.
Biology is the scientific study of living organisms, their structures, functions, growth, and interactions with each other and their environments.
The 15 branches of biology are:
- Anatomy
- Botany
- Zoology
- Microbiology
- Genetics
- Ecology
- Physiology
- Evolutionary Biology
- Cell Biology
- Molecular Biology
- Immunology
- Biotechnology
- Marine Biology
- Paleontology
- Biochemistry
The father of the cell in biology is Robert Hooke.