Chapter 11: Reproduction: How Life Continues

Reproduction is a biological process by which living organisms produce new individuals of their own kind.

Every living organism has a definite life span. It is born, grows, matures, reproduces and finally dies. Reproduction is important because it ensures that life continues on Earth.

For example, an old mango tree may die, but its seeds grow into new mango plants. Similarly, cows give birth to calves, dogs to puppies, cats to kittens and humans to children.

There are two main types of reproduction:

• Asexual reproduction
• Sexual reproduction

Asexual Reproduction

In asexual reproduction, only one parent is involved. The offspring are almost exact copies of the parent.

Sexual Reproduction

In sexual reproduction, usually two parents are involved. The offspring get a mixture of characteristics from both parents. This produces variations among individuals.

These variations help organisms adapt to changing environments and may contribute to the formation of new species over many generations.

Asexual reproduction is a type of reproduction in which a single parent produces new individuals.

It is commonly seen in:

• Unicellular organisms like bacteria, amoeba and yeast
• Simple multicellular organisms like hydra and sponge
• Many plants

In asexual reproduction, the offspring are genetically identical to the parent because they are formed from only one parent. Such identical individuals are called clones.

Asexual reproduction is generally fast and helps organisms increase their population quickly when environmental conditions are favourable.

Vegetative Propagation in Plants

Many plants can produce new plants from their vegetative parts such as roots, stems and leaves. This method is called vegetative propagation.

Examples

• Potato and ginger grow from fleshy underground stems.
• Money plant grows from stem cuttings.
• Sugarcane grows from stem cuttings.
• Bryophyllum leaves produce tiny plantlets that grow into new plants.

Vegetative propagation involves only one parent, so the new plants are genetically identical to the parent plant.

Vegetative propagation is very useful in agriculture and horticulture because it helps farmers grow plants with desirable features on a large scale.

Scientists and horticulturists have developed several methods of vegetative propagation, such as:

• Cutting
• Grafting
• Layering
• Tissue culture

These methods help in producing large numbers of useful plants quickly and efficiently.

Advantages of Vegetative Propagation

• Fast method of reproduction

New plants can be produced quickly.

• Genetically identical plants

The new plants have the same desirable traits as the parent plant.

• Useful for seedless plants

Plants that do not produce viable seeds can be grown by vegetative propagation.

• Large-scale cultivation

Farmers can grow desirable crops on a large scale.

• Better quality crops

Plants with better fruits, flowers or yield can be multiplied.

• Tissue culture helps produce disease-free plants

Tissue culture is used to produce healthy plantlets, especially in crops like banana.

Cutting

Cutting is a method of vegetative propagation in which a part of the plant, usually a stem cutting, is planted in the soil to grow into a new plant.

Steps in Cutting

• A healthy shoot or stem is selected from the parent plant.
• A cutting of suitable length is taken.
• Leaves from the lower half of the cutting are removed.
• The cutting is inserted into soil mixed with compost.
• It is planted at an angle of about 45°–60°.
• It is watered regularly.
• After some time, roots and shoots develop and a new plant grows.

Examples

• Rose
• Sugarcane
• Money plant
• Hibiscus

Importance of Cutting

Cutting is a simple and common method used by gardeners and farmers to grow new plants quickly.

Grafting

Grafting is a method of vegetative propagation in which a stem piece from one plant is joined to a rooted plant of another variety.

The rooted plant is called the stock, and the stem piece inserted into it is called the scion.

Steps in Grafting

• A healthy rooted plant is selected as Plant A.
• A healthy stem piece from another plant is selected as Plant B.
• A slit or wound is made on a twig of Plant A.
• The stem cutting of Plant B is inserted into the slit.
• The joint is wrapped with cloth or film to protect it from pests and drying.
• The plant is watered regularly.
• After healing, Plant B grows along with Plant A.

Examples

• Rose
• Mango
• Citrus fruits
• Apple

Importance of Grafting

Grafting is useful because it combines the good qualities of two plants. For example, one plant may have strong roots, while another may produce better fruits or flowers.

Layering

Layering is a method of vegetative propagation in which a branch of a plant is bent and buried partly in the soil while still attached to the parent plant.

Steps in Layering

• A flexible and thin branch is selected.
• The middle part of the branch is buried under the soil.
• The branch is watered regularly.
• After 10–15 days, roots develop from the buried part.
• The rooted branch is cut from the parent plant.
• It grows independently as a new plant.

Examples

• Lemon
• Jasmine
• Bougainvillea
• Guava

Importance of Layering

Layering is useful for plants whose branches can bend easily. It allows the new plant to get food and water from the parent plant until roots develop.

Tissue Culture

Tissue culture is a modern method of vegetative propagation in which small parts of a plant are grown in a laboratory on a nutrient medium.

It is very useful in crops like banana.

Benefits of Tissue Culture

• Produces many plantlets quickly
• Produces healthy and disease-free plants
• Helps in high yield
• Useful for commercial farming

Sexual reproduction is a type of reproduction in which two parents usually take part in producing a new individual.

Both parents contribute genetic material to the offspring. Therefore, the offspring are not exact copies of the parents. They show variations.

In sexual reproduction, special reproductive cells called gametes are formed.

• Male gamete in animals: Sperm
• Female gamete in animals: Egg
• Male gametes in plants are present in pollen grains
• Female gametes in plants are present in ovules

A special type of cell division called meiosis helps in sexual reproduction.

Every species has a fixed number of chromosomes in its cells. Chromosomes are thread-like structures present in the nucleus. They carry genetic information.

Humans have 23 pairs of chromosomes, that is, 46 chromosomes in total.

What is Meiosis?

Meiosis is a special type of cell division that produces gametes.

In meiosis, the chromosome number is reduced to half.

• Normal body cell: Diploid
• Gamete: Haploid

In humans:

• Body cells have 46 chromosomes
• Sperm and egg have 23 chromosomes each

When sperm and egg fuse during fertilisation, the chromosome number becomes 46 again in the zygote.

How Meiosis Creates Variation

During meiosis, chromosomes are separated and distributed into gametes in different combinations. This produces many possible combinations of genetic characters.

Thus, each child receives a unique combination of chromosomes from the parents.

Importance of Variation

Variation is important because:

• It makes individuals different from one another.
• It helps organisms adapt to changes in the environment.
• It supports the survival of species.
• It contributes to evolution over many generations.

Flowering plants are called angiosperms. In these plants, the flower is the reproductive organ.

A complete flower has four main parts:

• Sepals
• Petals
• Stamens
• Pistil

Parts of a Flower

1. Sepals

Sepals are the green outer parts of a flower. They protect the flower in the bud stage.

2. Petals

Petals are usually colourful and attractive. They help attract pollinators like insects and birds.

3. Stamen

The stamen is the male reproductive part of a flower.

It has two parts:

• Filament
• Anther

The anther produces pollen grains, which contain male gametes.

4. Pistil

The pistil is the female reproductive part of a flower.

It has three parts:

• Stigma
• Style
• Ovary

The stigma receives pollen grains. The style connects stigma to ovary. The ovary contains ovules, and each ovule has an egg cell.

Pollination is the transfer of pollen grains from the anther to the stigma of a flower.

Pollination is necessary for the formation of fruits and seeds.

There are two main types of pollination:

• Self-pollination
• Cross-pollination

Self-Pollination

When pollen grains are transferred from the anther to the stigma of the same flower or another flower of the same plant, it is called self-pollination.

Features of Self-Pollination

• Only one plant is involved.
• It produces less variation.
• It can happen without external pollinators in some plants.

Cross-Pollination

When pollen grains are transferred from the anther of a flower of one plant to the stigma of a flower of another plant of the same type, it is called cross-pollination.

Features of Cross-Pollination

• Two plants of the same species are involved.
• It produces more variation.
• It often requires pollinating agents like insects, wind, water or birds.

Pollination usually depends on external agents called pollinators.

Common pollinating agents are:

• Wind
• Water
• Insects
• Birds

1. Pollination by Wind

Wind-pollinated plants produce light and small pollen grains in large numbers.

Examples

• Wheat
• Maize
• Rice

Features

• Pollen grains are small and light.
• Pollen grains are produced in very large numbers.
• Stigma is often long and feathery to catch pollen.

2. Pollination by Water

In some aquatic plants, pollen is carried by water currents.

Examples

• Vallisneria
• Hydrilla

3. Pollination by Insects

Many plants are pollinated by insects like bees and butterflies.

Examples

• Sunflower
• Hibiscus
• Marigold

Features

• Flowers are brightly coloured.
• Flowers produce nectar.
• Flowers may have fragrance.
• Pollen grains are sticky or spiny.
• Stigma is sticky to receive pollen.

4. Pollination by Birds

Some flowers are pollinated by birds.

Examples

• Coral tree
• Hibiscus

Pollinating Birds

• Indian white-eye
• Sunbirds

Reproductive Success in Pollination

Wind-pollinated plants produce a huge number of pollen grains because many pollen grains are wasted. Insect-pollinated plants produce fewer pollen grains but are often more efficient because insects directly carry pollen from one flower to another.

According to the chapter:

This shows that insect pollination is generally more efficient, while wind pollination depends on producing a very large number of pollen grains.

After pollination, pollen grains reach a compatible stigma. Then the pollen grain produces a pollen tube.

Steps of Fertilisation in Flowering Plants

• Pollen grain lands on the stigma.
• A pollen tube grows through the style.
• The male gamete travels through the pollen tube.
• The male gamete reaches the ovule.
• It fuses with the egg cell.
• This fusion is called fertilisation.
• The fertilised egg is called a zygote.
• The zygote develops into an embryo.
• The ovule develops into a seed.
• The ovary develops into a fruit.

Important Points

• Fusion of male and female gametes is called fertilisation.
• The fertilised egg is called a zygote.
• The zygote develops into an embryo.
• The ovule becomes the seed.
• The ovary becomes the fruit.

When conditions such as water, air and suitable temperature are available, the seed germinates and grows into a new plant.

Meet a Scientist – P. Maheshwari

P. Maheshwari is known as the Father of Indian Embryology.

Embryology is the study of the development of embryos and reproductive organs.

Contributions of P. Maheshwari

• He worked in the field of plant embryology.
• He developed the technique of in-vitro fertilisation in flowering plants.
• He successfully fused an egg and a male gamete in a test tube to create new hybrid plants.
• He was among the first scientists to grow plant embryos on artificial nutrient media.
• His book An Introduction to the Embryology of Angiosperms became a classic work.

Animals reproduce by asexual and/or sexual reproduction.

In sexual reproduction, male and female gametes must meet and fuse. This fusion is called fertilisation.

There are two main types of fertilisation in animals:

• External fertilisation
• Internal fertilisation

External Fertilisation

In external fertilisation, fusion of sperm and egg takes place outside the body of the female.

Examples

• Frogs
• Most fish

In frogs and many fish, the female releases eggs into water, and the male releases sperm over them. Fertilisation occurs in water.

Features

• A large number of eggs are produced.
• Many eggs and young ones are destroyed by water currents or eaten by other animals.
• Survival rate is usually low.

Internal Fertilisation

In internal fertilisation, fusion of sperm and egg takes place inside the body of the female.

Examples

• Reptiles
• Birds
• Mammals

Features

• Fewer eggs or young ones are produced.
• The embryo is better protected.
• Chances of survival are higher than in external fertilisation.

Animals show different reproductive strategies. The main challenge in all animals is to ensure that:

• Male and female gametes meet.
• Young ones survive long enough to grow and reproduce.

Variation in Reproductive Strategies

Larval Stage

Fish, amphibians and insects produce many eggs. These eggs contain yolk, but usually only enough to support development up to a larval stage.

A larva is an intermediate stage in development. It feeds and grows before transforming into an adult.

Example: Butterfly Life Cycle

The life cycle of a butterfly includes:

Egg → Larva → Pupa → Adult

This transformation from larva to adult is called metamorphosis.

Reptiles, Birds and Mammals

• Reptiles and birds lay eggs with enough yolk to nourish the embryo.
• In mammals, the zygote develops inside the female body.
• Mammals usually feed their young ones with breast milk after birth.

Human beings reproduce by sexual reproduction.

In humans, male and female reproductive systems produce gametes.

• Male gamete: Sperm
• Female gamete: Egg

When sperm and egg fuse, a zygote is formed. The zygote develops into an embryo and later into a foetus in the uterus.

Reproductive maturity is the stage when reproductive organs become mature and start producing gametes.

This happens during puberty.

During puberty, physical and emotional changes occur in boys and girls.

In Boys

• Testes begin producing sperm.
• Voice may become deeper.
• Shoulders may broaden.
• Facial and body hair may appear.

In Girls

• Ovaries begin releasing eggs.
• Menstrual cycle begins.
• Body changes occur due to hormones.

Reproductive maturity means the body becomes capable of reproduction, but it does not mean a person is emotionally or socially ready for adult responsibilities.

The male reproductive system produces sperm and helps transfer them to the female reproductive system.

Main Parts of the Male Reproductive System

• Testes
• Scrotum
• Vas deferens
• Urethra
• Seminal vesicles
• Prostate gland
• Penis

1. Testes

Testes are two oval-shaped organs that produce sperm.

They also produce hormones that control sperm production and bring about changes during puberty.

2. Scrotum

The scrotum is a pouch of skin that contains the testes.

It keeps the testes slightly cooler than normal body temperature, which is necessary for sperm formation.

3. Vas Deferens

The vas deferens is a long tube through which sperm travel from the testes.

4. Urethra

The urethra is a common passage for urine and sperm.

5. Seminal Vesicles and Prostate Gland

These glands add fluids that:

• Nourish the sperm
• Help sperm remain active
• Help sperm move

6. Sperm

Each sperm has:

• A head containing genetic material
• A tail that helps it swim towards the egg

The female reproductive system produces eggs and supports the development of the baby.

Main Parts of the Female Reproductive System

• Ovaries
• Oviducts/Fallopian tubes
• Uterus
• Cervix
• Vagina

1. Ovaries

The ovaries produce female gametes called eggs.

They also release hormones that bring about changes during puberty.

2. Oviducts/Fallopian Tubes

The oviducts connect each ovary to the uterus.

The egg travels through the oviduct after ovulation. Fertilisation usually occurs in the oviduct.

3. Uterus

The uterus is a bag-like muscular organ where the embryo and foetus develop.

4. Cervix

The cervix is the narrow passage between the uterus and the vagina.

5. Vagina

The vagina is the passage that connects the uterus to the outside of the body.

Meet a Scientist – Subhash Mukhopadhyay

Subhash Mukhopadhyay was an Indian scientist associated with the history of in-vitro fertilisation in India.

In-vitro Fertilisation

In-vitro fertilisation, or IVF, is a medical technique in which an egg and sperm are combined outside the female body, usually in a laboratory dish.

The fertilised egg is then placed in the uterus to begin pregnancy.

A baby born through this method is commonly called a test tube baby, although the process actually happens in a culture dish, not in a test tube.

In 1978, Subhash Mukhopadhyay of Kolkata pioneered India’s first test tube baby, Kanupriya Agarwal, also known as Durga.

The process of formation of gametes is called gametogenesis.

Gametogenesis occurs in:

• Testes in males
• Ovaries in females

Gametes are formed by meiosis.

In humans:

• Body cells have 46 chromosomes
• Sperm has 23 chromosomes
• Egg has 23 chromosomes
• Zygote has 46 chromosomes

This maintains the chromosome number from one generation to the next.

Difference Between Sperm and Egg

The sperm is small and motile, while the egg is large and contains stored nutrients.

From puberty onwards, usually one mature egg is released every month from one of the ovaries. This process is called ovulation.

Before ovulation, the inner lining of the uterus becomes thick and rich in blood vessels.

Steps

• An egg is released from the ovary.
• The egg enters the oviduct.
• Sperm may reach the egg in the oviduct.
• If one sperm fuses with the egg, a zygote is formed.
• The zygote divides repeatedly by mitosis.
• It travels to the uterus.
• It attaches to the inner lining of the uterus.
• This attachment is called implantation.
• Implantation marks the beginning of pregnancy.

• Ovulation: Release of a mature egg from the ovary.
• Fertilisation: Fusion of sperm and egg.
• Zygote: Fertilised egg.
• Implantation: Attachment of the developing embryo to the uterus lining.
• Pregnancy: Period during which the embryo/foetus develops in the uterus.

If the egg is not fertilised, it remains alive for about a day and then degenerates.

The thick inner lining of the uterus is no longer needed. Therefore, it breaks down and comes out of the body through the vagina along with some blood.

This process is called menstruation or period.

Menstruation

Menstruation is the shedding of the inner lining of the uterus along with blood when fertilisation does not occur.

It usually lasts for 3 to 7 days.

The menstrual cycle usually repeats every 21 to 35 days, often around 28 days.

Key Stages of a Typical 28-Day Menstrual Cycle

If fertilisation does not happen, the lining begins to break down and the cycle repeats.

Important Note

Ovulation does not always happen exactly on day 14. The timing may vary from person to person and cycle to cycle.

What Determines a Baby’s Biological Sex?

Humans have two sex chromosomes.

• Females have XX chromosomes
• Males have XY chromosomes

The mother always contributes an X chromosome. The father contributes either an X chromosome or a Y chromosome.

• X from mother + X from father = XX female
• X from mother + Y from father = XY male

Therefore, the father’s sperm determines the biological sex of the baby.

Bridging Science and Society – Hygiene Practices to Follow During Menstruation

Menstruation is a natural and healthy process. Proper hygiene during menstruation helps maintain health and cleanliness.

Menstrual Hygiene Practices

• Use clean menstrual products

Use sanitary pads, tampons, menstrual cups or reusable pads.

• Wash regularly

Clean the genital area with water. Avoid using harsh soaps.

• Wash hands properly

Always wash hands with soap and water before and after changing menstrual products.

• Dispose of used products properly

Wrap used pads in paper or wrapper and throw them in a bin. Do not flush them.

• Care for reusable products

Reusable pads should be washed and dried properly as instructed.

• Change products regularly

Pads should generally be changed every 4–6 hours, or more often if needed.

Period is Your Pride

Menstruation is a sign of a healthy reproductive system.

It should not be treated as something shameful. Using clean menstrual products, changing them regularly and disposing of them responsibly helps maintain personal hygiene and keeps surroundings clean.

Pregnancy in humans lasts about nine months.

It is divided into three stages called trimesters.

First Trimester

In the first trimester:

• The fertilised egg develops into an embryo.
• Major organs start forming.
• From about the ninth week, the developing embryo is called a foetus.

Second Trimester

In the second trimester:

• The foetus grows bigger and stronger.
• The mother may start feeling movements of the foetus.

Third Trimester

In the third trimester:

• The baby grows rapidly.
• The baby prepares for life outside the womb.

During childbirth, strong contractions of the uterus help push the baby out through the birth canal. In some cases, doctors may use medical or surgical methods to deliver the baby safely.

Care After Birth

After birth, a baby needs special care.

Important Care for Newborns

• Breastfeeding
• Keeping the baby warm
• Timely vaccination
• Gentle handling
• Clean surroundings

Breastfeeding is important because mother’s milk provides complete nutrition and protects the baby from many diseases.

A mother’s health during pregnancy is very important for the baby’s growth and safety.

Important Practices During Pregnancy

• Eat a balanced diet rich in proteins, vitamins and minerals.
• Attend regular medical check-ups.
• Follow the doctor’s advice about light exercise and rest.
• Avoid harmful habits such as smoking and alcohol.
• Avoid taking medicines without medical advice.
• Maintain emotional well-being.
• Get support from family members.

Post-Partum Depression

Some mothers may feel anxiety, sadness or tiredness after delivery. This condition is called post-partum depression. It is a recognised condition and can be treated.

Mothers should talk to a doctor, nurse or ASHA worker if they feel very low or overwhelmed.

Role of ASHA Workers

ASHA workers help in:

• Hygiene awareness
• Immunisation
• Family planning
• Maternal care
• Safe deliveries
• Contraceptive guidance

Sexual maturity means the body becomes capable of reproduction.

In boys, this includes production of sperm. In girls, this includes the beginning of menstrual cycles.

However, sexual maturity does not mean that a person is fully ready for adult responsibilities.

Sexual Maturity vs Emotional Maturity

Sexual maturity is related to physical ability to reproduce.

Emotional maturity means being able to:

• Handle feelings responsibly
• Communicate clearly
• Make thoughtful decisions
• Understand responsibilities

Emotional maturity usually takes longer to develop than physical maturity.

Responsible choices help prevent:

• Unplanned pregnancies
• Sexually transmitted infections
• Health risks

Sexually Transmitted Infections

Some infections can spread through close sexual contact. These are called Sexually Transmitted Infections, or STIs.

Examples of STIs

• Gonorrhoea
• Herpes
• Syphilis
• Genital warts
• HIV, which can lead to AIDS

Some STIs are not curable yet. Therefore, prevention is very important.

Contraceptive Methods

Contraceptives are methods used to prevent pregnancy.

1. Barrier Methods

These stop sperm from reaching the egg.

Examples:

• Condoms
• Vaginal covers

Condoms also help reduce the spread of STIs.

2. Oral Pills

Oral contraceptive pills change hormone levels and prevent the release of eggs. They should be used only with proper medical guidance because they may have side effects.

3. Intra-Uterine Devices

Intra-Uterine Devices, or IUDs, are placed in the uterus to prevent pregnancy.

Example:

• Copper-T

4. Surgical Methods

Surgical methods prevent sperm and egg from meeting.

Examples:

• Blocking the vas deferens in males
• Blocking the fallopian tubes in females

Important Social Message

Prenatal sex determination is strictly prohibited by law in India. This is important because sex-selective abortion can disturb the sex ratio and harm society.

At a Glance – Summary

Reproduction is the biological process by which living organisms produce new individuals of the same species.

There are two main types of reproduction: asexual reproduction and sexual reproduction.

In asexual reproduction, only one parent is involved, and the offspring are generally genetically identical to the parent. It occurs through methods such as budding, spore formation and vegetative propagation.

Vegetative propagation is a method in plants where new plants develop from vegetative parts such as stems, roots or leaves. Important methods include cutting, grafting, layering and tissue culture.

In sexual reproduction, two parents usually contribute genetic material. This produces variation, which helps organisms adapt and survive.

Meiosis is a special type of cell division that produces gametes with half the number of chromosomes. It helps maintain chromosome number and creates variation.

In flowering plants, the flower is the reproductive organ. The stamen is the male part, and the pistil is the female part.

Pollination is the transfer of pollen grains from the anther to the stigma. It may be self-pollination or cross-pollination.

Pollination can occur through agents like wind, water, insects and birds.

After pollination, the pollen tube carries the male gamete to the ovule. The fusion of male and female gametes is called fertilisation. The fertilised egg becomes a zygote, the ovule becomes a seed, and the ovary becomes a fruit.

In animals, fertilisation may be external or internal. External fertilisation occurs outside the body, as in frogs and fish. Internal fertilisation occurs inside the female body, as in reptiles, birds and mammals.

Human beings reproduce by sexual reproduction. The male reproductive system produces sperm, and the female reproductive system produces eggs.

In humans, sperm and egg contain 23 chromosomes each. When they fuse, they form a zygote with 46 chromosomes.

If fertilisation occurs, the zygote develops into an embryo and pregnancy begins. If fertilisation does not occur, the uterine lining breaks down and menstruation takes place.

Menstruation is a normal and healthy process. Proper menstrual hygiene is important for health and cleanliness.

Pregnancy in humans lasts about nine months and is divided into three trimesters.

A mother’s health during pregnancy is important for the baby’s growth. She needs proper nutrition, rest, medical check-ups and emotional support.

Sexual maturity means the body becomes capable of reproduction, but emotional maturity and responsible decision-making are equally important.

Unwanted pregnancies and STIs can be prevented through responsible choices and contraceptive methods such as condoms, pills, IUDs and surgical methods.

Important Keywords and Definitions for Class 9

1. Reproduction

Reproduction is the biological process by which living organisms produce new individuals of their own kind.

2. Life Span

Life span is the period from the birth of an organism to its death.

3. Asexual Reproduction

Asexual reproduction is a type of reproduction in which only one parent is involved and the offspring are almost genetically identical to the parent.

4. Sexual Reproduction

Sexual reproduction is a type of reproduction in which two parents usually take part and the offspring inherit a mix of characteristics from both parents.

5. Offspring

Offspring means the young one produced by an organism through reproduction.

6. Variation

Variation means the differences found among individuals of the same species.

7. Species

A species is a group of organisms that are similar and can reproduce among themselves to produce offspring of their own kind.

8. Vegetative Propagation

Vegetative propagation is a type of asexual reproduction in plants in which new plants arise from vegetative parts such as roots, stems or leaves.

9. Vegetative Parts

Vegetative parts are the non-reproductive growing parts of a plant, such as root, stem and leaf.

10. Clone

A clone is an organism that is genetically identical to its parent.

11. Cutting

Cutting is a method of vegetative propagation in which a part of a plant, usually a stem cutting, is planted in soil to grow into a new plant.

12. Grafting

Grafting is a method of vegetative propagation in which a stem piece of one plant is joined to a rooted plant of another variety so that both grow together.

13. Stock

Stock is the rooted plant used in grafting, on which another plant part is attached.

14. Scion

Scion is the stem cutting or shoot of a plant that is attached to the stock during grafting.

15. Layering

Layering is a method of vegetative propagation in which a branch of a plant is bent and partly buried in soil until it develops roots.

16. Tissue Culture

Tissue culture is a modern method of growing plants in which a small part of a plant is grown on a nutrient medium under controlled conditions.

17. Budding

Budding is a type of asexual reproduction in which a small outgrowth called a bud develops on the parent body and later separates to form a new individual.

18. Bud

A bud is a small outgrowth on the body of an organism that can grow into a new individual.

19. Spore Formation

Spore formation is a method of asexual reproduction in which organisms produce tiny reproductive structures called spores.

20. Spores

Spores are tiny, lightweight reproductive structures that can grow into new individuals under favourable conditions.

21. Hyphae

Hyphae are thread-like structures found in fungi.

22. Mitosis

Mitosis is a type of cell division in which one cell divides to form two daughter cells with the same number of chromosomes as the parent cell.

23. Daughter Cells

Daughter cells are the new cells formed after cell division.

24. Chromosomes

Chromosomes are thread-like structures present in the nucleus of a cell. They carry genetic information.

25. Genetic Information

Genetic information is the information carried by chromosomes that controls the characteristics of an organism.

26. Meiosis

Meiosis is a special type of cell division that forms gametes with half the number of chromosomes.

27. Gametes

Gametes are reproductive cells involved in sexual reproduction.

Examples: sperm in males and egg in females.

28. Diploid Cell

A diploid cell is a cell that has the full set of chromosomes.

In humans, diploid cells have 46 chromosomes.

29. Haploid Cell

A haploid cell is a cell that has half the number of chromosomes.

In humans, sperm and egg are haploid cells with 23 chromosomes each.

30. Sperm

Sperm is the male gamete in animals and humans.

31. Egg

Egg is the female gamete in animals and humans.

32. Flower

A flower is the reproductive organ of a flowering plant.

33. Angiosperms

Angiosperms are flowering plants that produce seeds inside fruits.

34. Sepal

Sepal is the green outer part of a flower that protects the flower in the bud stage.

35. Petal

Petal is the coloured and often attractive part of a flower that helps attract pollinators.

36. Stamen

Stamen is the male reproductive part of a flower.

37. Filament

Filament is the stalk-like part of the stamen that supports the anther.

38. Anther

Anther is the part of the stamen that produces pollen grains.

39. Pollen Grain

Pollen grain is a tiny structure produced by the anther. It contains the male gamete in flowering plants.

40. Pistil

Pistil is the female reproductive part of a flower.

41. Stigma

Stigma is the sticky or flat top part of the pistil that receives pollen grains.

42. Style

Style is the tube-like part of the pistil that connects the stigma to the ovary.

43. Ovary

Ovary is the swollen lower part of the pistil that contains ovules.

44. Ovule

Ovule is a structure inside the ovary that contains the female gamete or egg cell. After fertilisation, it develops into a seed.

45. Pollination

Pollination is the transfer of pollen grains from the anther to the stigma of a flower.

46. Self-Pollination

Self-pollination is the transfer of pollen grains to the stigma of the same flower or another flower of the same plant.

47. Cross-Pollination

Cross-pollination is the transfer of pollen grains from the flower of one plant to the flower of another plant of the same species.

48. Pollinators

Pollinators are agents that help transfer pollen grains from anther to stigma.

Examples: wind, water, insects and birds.

49. Fertilisation

Fertilisation is the fusion of the male gamete and the female gamete.

50. Pollen Tube

Pollen tube is a tube formed by a pollen grain after it lands on a compatible stigma. It carries the male gamete to the ovule.

51. Zygote

Zygote is the fertilised egg formed after the fusion of male and female gametes.

52. Embryo

Embryo is the early developing stage of a new organism formed from the zygote.

53. Seed

A seed is formed from the ovule after fertilisation. It contains the embryo of the plant.

54. Fruit

A fruit is formed from the ovary of a flower after fertilisation.

55. Seed Dispersal

Seed dispersal is the process by which seeds are spread away from the parent plant by wind, water or animals.

56. Germination

Germination is the process by which a seed develops into a new plant under favourable conditions.

57. External Fertilisation

External fertilisation is the fusion of male and female gametes outside the body of the female.

Examples: frog and fish.

58. Internal Fertilisation

Internal fertilisation is the fusion of male and female gametes inside the body of the female.

Examples: reptiles, birds and mammals.

59. Larva

A larva is an immature stage in the life cycle of some animals. It feeds, grows and later changes into the adult form.

60. Pupa

Pupa is the resting stage in the life cycle of insects like butterflies, during which the larva changes into an adult.

61. Metamorphosis

Metamorphosis is the process by which a larva changes into an adult.

62. Reproductive Maturity

Reproductive maturity is the stage when reproductive organs mature and start producing gametes.

63. Puberty

Puberty is the stage of life during which the body undergoes physical and emotional changes and becomes capable of reproduction.

64. Male Reproductive System

The male reproductive system is a group of organs that produce sperm and help transfer them to the female body.

65. Testes

Testes are male reproductive organs that produce sperm and male hormones.

66. Scrotum

Scrotum is a pouch of skin that holds the testes and keeps them slightly cooler than normal body temperature.

67. Vas Deferens

Vas deferens is a tube through which sperm travel from the testes towards the urethra.

68. Urethra

Urethra is the common passage for urine and sperm in males.

69. Seminal Vesicles

Seminal vesicles are glands that add fluid to nourish sperm and help them move.

70. Prostate Gland

Prostate gland is a gland that adds fluid to sperm and helps sperm remain active.

71. Female Reproductive System

The female reproductive system is a group of organs that produce eggs and support fertilisation, pregnancy and childbirth.

72. Ovaries

Ovaries are female reproductive organs that produce eggs and female hormones.

73. Oviducts / Fallopian Tubes

Oviducts or fallopian tubes are tubes that connect the ovaries to the uterus. Fertilisation usually occurs here.

74. Uterus

Uterus is a bag-like muscular organ where the embryo and foetus develop during pregnancy.

75. Cervix

Cervix is the narrow passage between the uterus and the vagina.

76. Vagina

Vagina is the passage that connects the uterus to the outside of the body.

77. Gametogenesis

Gametogenesis is the process of formation of gametes.

78. Ovulation

Ovulation is the release of a mature egg from the ovary.

79. Implantation

Implantation is the attachment of the developing embryo to the inner lining of the uterus.

80. Pregnancy

Pregnancy is the condition in which the embryo or foetus develops inside the uterus.

81. Menstruation

Menstruation is the shedding of the inner lining of the uterus along with some blood when fertilisation does not occur.

82. Menstrual Cycle

Menstrual cycle is the monthly cycle of ovulation, preparation of the uterus and menstruation.

83. Menopause

Menopause is the stage in life when menstrual cycles stop permanently, usually around the age of 50.

84. Sex Chromosomes

Sex chromosomes are chromosomes that determine the biological sex of a baby.

Females have XX chromosomes and males have XY chromosomes.

85. Foetus

Foetus is the developing baby inside the uterus after the early embryonic stage.

86. Trimester

A trimester is one of the three stages of pregnancy. Each trimester lasts about three months.

87. Childbirth

Childbirth is the process by which the baby is delivered from the mother’s body.

88. Breastfeeding

Breastfeeding is feeding the baby with mother’s milk. It provides nutrition and protection from many diseases.

89. Post-Partum Depression

Post-partum depression is a condition in which a mother may feel anxiety, sadness or fatigue after childbirth. It can be treated with proper help and support.

90. Sexually Mature

A person is sexually mature when the body becomes capable of producing gametes and reproduction.

91. Emotional Maturity

Emotional maturity means the ability to handle feelings, communicate clearly and make thoughtful decisions.

92. Sexually Transmitted Infections

Sexually Transmitted Infections, or STIs, are infections that can spread through sexual contact.

Examples: gonorrhoea, herpes, syphilis, genital warts and HIV.

93. HIV

HIV is a virus that affects the immune system and can eventually lead to AIDS.

94. AIDS

AIDS is a serious disease caused by HIV, in which the body’s immune system becomes very weak.

95. Contraception

Contraception means methods used to prevent pregnancy.

96. Contraceptives

Contraceptives are devices or methods used to prevent pregnancy.

Examples: condoms, oral pills and IUDs.

97. Condom

A condom is a barrier contraceptive that prevents sperm from reaching the egg and also helps reduce the spread of STIs.

98. Oral Contraceptive Pills

Oral contraceptive pills are medicines that prevent pregnancy by changing hormone levels and affecting the release of eggs.

99. Intra-Uterine Device

An Intra-Uterine Device, or IUD, is a contraceptive device placed in the uterus to prevent pregnancy.

100. Copper-T

Copper-T is a type of IUD used to prevent pregnancy.

101. Abortion

Abortion is the medical removal of an unwanted pregnancy, generally within the first trimester under proper medical supervision.

102. IVF

IVF, or In-vitro Fertilisation, is a medical technique in which an egg and sperm are combined outside the female body in a laboratory dish.

103. Test Tube Baby

A test tube baby is a baby born through IVF, although fertilisation actually occurs in a laboratory culture dish, not in a test tube.

104. Plant Breeding

Plant breeding is the process of developing improved plant varieties with desirable characteristics.

105. Selective Breeding

Selective breeding is a method in which plants or animals with desirable characters are selected for reproduction.

106. Artificial Hybridisation

Artificial hybridisation is the manual transfer of pollen with desired characters to produce new varieties of plants.

107. Genetic Engineering

Genetic engineering is the process of inserting genetic material with desired characters into the DNA of selected varieties.

108. ASHA Worker

An ASHA worker is a trained community health worker who helps people with hygiene, immunisation, maternal care, safe deliveries and family planning.

109. Hygiene

Hygiene means practices that help maintain health and prevent diseases.

110. Menstrual Hygiene

Menstrual hygiene means using clean menstrual products, changing them regularly and disposing of them properly during menstruation.