Topic
Uyiriyal - Biological
🧬 Biological Theories (Uyiriyal Kotpaadugal / Biological Theories) – Full explanation
Biological theories explain how organisms form, grow and function Important scientific concepts. These are considered the basic pillars of biological science.
1. Cell Theory
All living things are made up of cells. Cell is the basic unit of life.
- ✔ All living things are made up of cells
- ✔ Cell = basic unit of life
- ✔ New cells are formed from old cells
🧬 2. Genetic Theory
The transmission of traits from parents to children is called heredity. This was explained by Gregor Mendel.
- ✔ Traits are transmitted through DNA
- ✔ Mendel – Father of Genetics
🌱 3. Theory of Evolution
Organisms change over time and evolve into new species. Charles Darwin explained this through his theory of Natural Selection.
- ✔ Survival of the fittest
- ✔ Natural selection
4. Germ Theory of Disease
The theory that diseases are caused by microorganisms. This was explained by Louis Pasteur and Robert Koch.
- ✔ Diseases are caused by germs
- ✔ Pasteur, Koch – prominent scientists
🌍 5. Origin of Life
There are many theories about how life originated on Earth. Mainly the theories of “Abiogenesis” and “Biogenesis” are discussed.
- ✔ Abiogenesis – Life from non-life
- ✔ Biogenesis – Life from life
Key Notes (TNPSC):
- ✔ Cell theory – the basis of life
- ✔ Mendel – Father of Genetics
- ✔ Darwin – Evolution
- ✔ Pasteur – Germ theory
TNPSC Exams include “Who is Cell theory?”, “What did Darwin say?”, “What is Germ theory?” Questions like Frequently asked questions from this topic.
Therefore, Biological Principles is very important basic topic in Biology course.
🧬 Classification (Vagaippadu / Classification) – Full description
Classification is the classification of organisms based on their similarities and differences A method of grouping. It helps to understand organisms easily.
📘 Classification requirements
- ✔ To identify organisms easily
- ✔ To group similar organisms together
- ✔ To understand the relationships of organisms
👨🔬 The father of classification
Carl Linnaeus is known as the father of taxonomy. He introduced Binomial Nomenclature.
🏷️ Binomial naming system
Each creature is given two names:
- ✔ Genus
- ✔ Species
Example: Man –Homo sapiens
🌍 Five Kingdom Classification
- 1. Monera:Bacteria
- 2. Protista:Amoeba
- 3. Fungi:Yeast, mushroom
- 4. Plantae:Plants
- 5. Animalia:Man, animals
📊 Levels of Classification (Taxonomic Hierarchy)
- ✔ Kingdom
- ✔ Phylum
- ✔ Class
- ✔ Order
- ✔ Family
- ✔ Genus
- ✔ Species
💡 Key features
- ✔ Regulates organisms
- ✔ Helps in scientific research
- ✔ Globally uniform naming scheme
Key Notes (TNPSC):
- ✔ Linnaeus – Father of Taxonomy
- ✔ Homo sapiens – Human
- ✔ 5 Kingdom classification
- ✔ Taxonomy levels are important
“Who is Linnaeus?”, “What is 5 kingdom?”, “What is Homo sapiens?” in TNPSC exams. Questions like Frequently asked questions from this topic.
Therefore, classification is a very important basic topic in biology.
🌱 Evolution (Parinamam / Evolution) – Full explanation
Evolution is the gradual change in organisms over time It is the process of forming new species. It is an important biological theory that explains the development and change of organisms.
👨🔬 Father of Evolution
Charles Darwin is known as the father of the theory of evolution. He proposed the theory of “Natural Selection”.
🌿 Natural Selection
Organisms that have characteristics that suit their environment survive and thrive. Those without suitable properties perish.
- ✔ Survival of the fittest
- ✔ Adaptation to environment
🧬 Sources for evolution
- ✔ Fossils:Evidence of ancient organisms
- ✔ Homologous structures:Single source system
- ✔ Analogous structures:Same function
- ✔ Genetic evidence:DNA similarities
🔄 Stages of Evolution
- ✔ Variation
- ✔ Competition
- ✔ Natural Selection
- ✔ Creation of new species (Speciation)
📊 Example
Giraffe is the only animal with a long neck Living and growing because of more food is said to be an example of evolution.
💡 Key features
- ✔ Organisms are not static – they change
- ✔ Environment plays an important role
- ✔ New species are formed
Key Notes (TNPSC):
- ✔ Darwin – Evolution
- ✔ Natural Selection is important
- ✔ Fossils – evidence
- ✔ Survival of the fittest
“Who is Darwin?”, “What is natural selection?”, “What are fossils?” in TNPSC exams. Questions like Frequently asked questions from this topic.
Therefore, evolution is a very important basic topic in biology.
🧬 Genetics (Marapiyal / Genetics) – Full explanation
Genetics refers to the traits (traits) in organisms from parents The branch of science that deals with how things are passed down to offspring.
👨🔬 Father of Genetics
Gregor Mendel is known as the father of genetics. He studied the pea plant and discovered genetic rules.
📘 Key concepts
- ✔ Gene:The unit that controls properties
- ✔ DNA:Material containing genetic information
- ✔ Chromosome:A system that carries genes
- ✔ Traits:Height, color etc
⚡ Mendel's Laws
1. Law of Segregation
Two alleles for a trait are segregated and transmitted separately.
2. Law of Independent Assortment
Different properties are transmitted independently of each other.
🧬 Dominant & Suppressive Characteristics
- ✔ Dominant:Emergent characteristic
- ✔ Recessive:A latent trait
📊 Example
T is dominant in the traits Tall (T) and Short (t). TT or Tt → Tall, tt → Short.
💡 Key features
- ✔ Traits are passed down through generations
- ✔ DNA plays an important role
- ✔ Gene = genetic unit
Key Notes (TNPSC):
- ✔ Mendel – Father of Genetics
- ✔ Gene = Trait unit
- ✔ Dominant / Recessive
- ✔ DNA is important
“Who is Mendel?”, “What is Gene?”, “What is Dominant?” in TNPSC Exams. Questions like Frequently asked questions from this topic.
Therefore, genetics is a very important basic topic in biology.
🧬 Genetics (Marapiyal / Genetics) – Full explanation
Genetics refers to the traits (traits) in organisms from parents The branch of science that deals with how things are passed down to offspring.
👨🔬 Father of Genetics
Gregor Mendel is known as the father of genetics. He studied the pea plant and discovered genetic rules.
📘 Key concepts
- ✔ Gene:The unit that controls properties
- ✔ DNA:Material containing genetic information
- ✔ Chromosome:A system that carries genes
- ✔ Traits:Height, color etc
⚡ Mendel's Laws
1. Law of Segregation
Two alleles for a trait are segregated and transmitted separately.
2. Law of Independent Assortment
Different properties are transmitted independently of each other.
🧬 Dominant & Suppressive Characteristics
- ✔ Dominant:Emergent characteristic
- ✔ Recessive:A latent trait
📊 Example
T is dominant in the traits Tall (T) and Short (t). TT or Tt → Tall, tt → Short.
💡 Key features
- ✔ Traits are passed down through generations
- ✔ DNA plays an important role
- ✔ Gene = genetic unit
Key Notes (TNPSC):
- ✔ Mendel – Father of Genetics
- ✔ Gene = Trait unit
- ✔ Dominant / Recessive
- ✔ DNA is important
“Who is Mendel?”, “What is Gene?”, “What is Dominant?” in TNPSC Exams. Questions like Frequently asked questions from this topic.
Therefore, genetics is a very important basic topic in biology.
🏥 Udal Nalam / Health – Full explanation
Health refers to the state of balance of body, mind and social welfare. True health is complete health, not merely the absence of disease.
📘 Elements of health
- ✔ Physical Health:Physical health
- ✔ Mental Health:Peace of mind and well being
- ✔ Social Health:Social relations
🥗 Tips for good health
- ✔ Balanced Diet
- ✔ Regular Exercise
- ✔ Hygiene
- ✔ Adequate sleep
- ✔ Stress management
🦠 Types of diseases
1. Communicable Diseases
- ✔ Spread by germs
- ✔ Eg: Fever, Tuberculosis
2. Non-Communicable Diseases
- ✔ Non-communicable diseases
- ✔ Eg: diabetes, blood pressure
💉 Prevention methods
- ✔ Vaccination
- ✔ Clean water
- ✔ Sanitation
- ✔ Medical examination
🌿 Importance of hygiene
- ✔ Prevents diseases
- ✔ Increases longevity
- ✔ Improves quality of life
Key Notes (TNPSC):
- ✔ Health = Physical + Mental + Social
- ✔ Balanced diet is important
- ✔ Vaccination is important
- ✔ Hygiene = Health
“Health definition?”, “Communicable disease?”, “What is vaccination?” in TNPSC exams. Questions like Frequently asked questions from this topic.
Therefore, health is a very important topic in biology and general science subjects.
🦠 Human Diseases (Manidha Noigal / Human Diseases) – Full explanation
Human diseases are conditions in which the normal functions of the human body are affected. These are caused by germs, lifestyle or genetics.
📘 Types of diseases
1. Communicable Diseases
Diseases spread from one person to another.
- ✔ Virus – Flu, COVID-19
- ✔ Bacteria – Tuberculosis
- ✔ Parasite – Malaria
2. Non-Communicable Diseases
Non-communicable diseases are usually caused by lifestyle or genetics.
- ✔ Diabetes
- ✔ Hypertension
- ✔ Heart diseases
🦠 Causes of diseases
- ✔ Microorganisms
- ✔ Lack of cleanliness
- ✔ Lack of nutritious food
- ✔ Genetic causes
💉 Prevention methods
- ✔ Vaccination
- ✔ Hygiene
- ✔ Clean drinking water
- ✔ Balanced diet
⚕️ Treatment methods
- ✔ Medicines
- ✔ Surgery
- ✔ Natural medicine
📊 Examples
| disease | The reason | Type |
|---|---|---|
| Malaria | Parasite | Epidemic |
| Tuberculosis | Bacteria | Epidemic |
| diabetes | way of life | Non-communicable disease |
Key Notes (TNPSC):
- ✔ Communicable vs Non-communicable
- ✔ Vaccination is important
- ✔ Hygiene is important
- ✔ Microorganisms cause
TNPSC Exams include “Cause of Malaria?”, “What is a Communicable Disease?”, “What is the Type of Diabetes?” Questions like Frequently asked questions from this topic.
Therefore, human diseases are a very important topic in biology and general science subjects.
People Also Ask
Quick answers for common questions
The science of living things and their activities.
Cell
Plant cell → has a cell wall
Animal cell → no cell wall
Animal cell → no cell wall
The process by which plants use sunlight to make food.
Skin
Transporting oxygen and nutrients to all parts of the body.
A molecule that contains genetic information.
The process of producing energy in the body.
A small biological unit that is neither living nor non-living.
Protects the body from diseases.
