How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter

• Introduction : How do Organisms Reproduce Class 10 
• Types of Reproduction
  • Asexual Reproduction
  • Sexual Reproduction
• Methods of Asexual Reproduction
  • Fission
  • Fragmentation
  • Regeneration
  • Budding
  • Vegetative Propagation
  • Artificial Vegetative Propagation Methods
  • Benefits of Tissue Culture
• Sexual Reproduction
  • Reproduction in Plants
  • Types of Flowers
  • Structure of a Flower
• Seed Germination Process
• Human Reproduction
  • Puberty Changes in Males and Females
  • Male Reproductive System
    • Testes and their Function
    • Vas Deferens
    • Urethra
    • Associated Glands
  • Female Reproductive System
    • Ovary
    • Oviduct (Fallopian Tube)
    • Uterus
• Fertilization of the Egg
  • When the Egg is Fertilized
  • When the Egg is Not Fertilized
• Reproductive Health
  • Sexually Transmitted Infections
  • Contraceptive Methods
  • Female Foeticide

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Introduction: How do Organisms Reproduce Class 10 Note

• Reproduction refers to the process by which living organisms produce offspring similar to themselves, ensuring the continuity of life on Earth.
• The nucleus of a cell contains DNA (Deoxyribonucleic Acid), which carries genetic information.
• DNA replicates and forms new cells that may show slight differences from the original cells, resulting in variations.
• Variations help species adapt and survive, driving the process of evolution.

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

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Types of Reproduction: 

1. Asexual Reproduction:

   • A single organism is capable of producing offspring without the involvement of gametes.
   • The offspring inherit the same genetic traits as the parent.
   • It is a quick and efficient method of reproduction.
   • Common in lower organisms such as bacteria, fungi, etc.

2. Sexual Reproduction:

   • Involves two individuals (male and female), each producing gametes.
   • The offspring are genetically similar but not identical to the parents.
   • This method fosters genetic diversity and is observed in higher organisms like humans, animals, and most plants.

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Modes of Asexual Reproduction

1. Fission

The parent organism splits into two or more daughter cells.

•  Binary fission: The parent divides into two identical cells. Example: amoeba.                                

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

• Multiple fission: The parent cell divides into several daughter cells. Example: Plasmodium.

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

2. Fragmentation: 

This process occurs in multicellular organisms with a simple body structure, such as Spirogyra. Spirogyra has a filament-like body, and when it breaks into smaller pieces or fragments, each fragment can grow into a new individual.

However, not all multicellular organisms can undergo cell-by-cell division because their cells are organized into tissues and organs, which are positioned in specific parts of the body. As a result, these organisms require more complex methods of reproduction.

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

3. Regeneration: 

This is the process by which organisms can regrow lost or damaged body parts. Some organisms have a remarkable ability to regenerate, and in certain cases, it serves as a form of reproduction. For instance, Planaria can reproduce through regeneration.

Regeneration involves specialized cells that divide to create a mass of cells, which then differentiate into various types of cells and tissues. This process follows a specific, organized sequence known as development.

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

4. Budding:

This process occurs in Hydra, where a small outgrowth, or bud, forms at the base of the parent Hydra. The bud increases in size and eventually detaches to live on its own.

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

5. Vegetative Propagation

• In many plants, new individuals can grow from vegetative parts like:

• From roots: Example: dahlias, sweet potato.

• From stems: Example: potato, ginger.

• From leaves: Example: bryophyllum (the notches on the leaves contain buds that develop into new plants). 

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

6. Artificial Methods of Vegetative Propagation

(i) Grafting: This involves joining the stem of one plant to the rootstock of another. Example: Mango.

(ii) Cutting: A part of the plant, such as a stem or leaf, is cut and placed in a suitable environment to grow into a new plant. Example: Rose.

(iii) Layering: A branch of the plant is bent to the ground and covered with soil, allowing it to form roots and develop into a new plant. Example: Jasmine.

(iv) Tissue Culture: New plants are grown from the growing tip of a plant.

• The plant cells are placed in a special culture medium, where they form a callus. The callus is then transferred to a hormone-rich medium to stimulate growth and differentiation.
• Example: Ornamental plants, orchids.

Benefits of Tissue Culture:

• Plants like banana, rose, and jasmine, which are incapable of producing seeds, can be propagated.
• The new plants are genetically identical to the parent plants.
• It supports the cultivation of seedless fruits.

7. Spore Formation:

 Spores are tiny, bulb-like structures that have a thick protective wall. Under suitable conditions, they germinate and grow into a new organism.
Example: Rhizopus.

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

Sexual Reproduction

• Sexual reproduction occurs when new organisms are produced through the fusion of male and female gametes.

• The process of gamete fusion is known as fertilization, which leads to genetic variation in the offspring.

Sexual Reproduction in Plants

• Flowers act as the reproductive structures in plants.

• A typical flower consists of four main parts: sepals, petals, stamen, and pistil.

Types of Flowers

• Bisexual Flower: A flower that has both male and female reproductive organs. 

Example: Hibiscus, mustard.

• Unisexual Flower: Has only one type of reproductive organ, either male or female, but not both.

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

Process of Seed Formation

Pollen grains, which are produced in the anther, are transferred to the stigma of the same flower (self-pollination) or to a different flower's stigma (cross-pollination) through various agents like wind, water, or animals.

• The pollen grains then germinate, forming pollen tubes that travel through the style to reach the ovules in the ovary.

• The fusion of the male and female gametes is called fertilization, resulting in the formation of a zygote inside the ovary.

• The zygote divides to form the embryo, and the ovule develops a thick protective coat, gradually transforming into a seed.

• The ovary develops into the fruit, while the remaining parts of the flower dry up and fall off.

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

Reproduction in Human Beings

• Humans reproduce through sexual reproduction.

• Sexual Maturation: This is the phase in life when the body begins to produce germ cells, such as eggs (ova) in females and sperm in males. This phase is known as puberty.

Changes During Puberty

Common Changes in Both Males and Females:

• Hair becomes thicker in areas like the armpits and genital region.
• The skin becomes more oily, often leading to pimples.

In Females:

• The breasts start to develop and grow.
• The onset of menstruation occurs.

In Males:

• Thick facial hair begins to grow.
• The voice starts to deepen or crack.

These changes indicate the onset of sexual maturity.

Male Reproductive System

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

(i) Testes

• The testes are a pair of organs located within the scrotum, which hangs outside the abdominal cavity.

• The scrotum maintains a slightly cooler temperature, which is essential for sperm production.

• The testes generate the male reproductive cells, known as sperm.

• The testes also produce the male sex hormone, testosterone.

Functions of the Testes:

• They regulate sperm production.

• They trigger physical changes during puberty.

(ii) Vas Deferens

• The vas deferens transports sperm from the testes to the urethra.

 

(iii) Urethra

• The urethra serves as a shared passageway for both sperm and urine. It is surrounded by the penis.

(iv) Associated Glands

• The seminal vesicles and prostate gland secrete fluids that mix with sperm, providing nourishment and facilitating their movement.

Female Reproductive System: 

It is made up of the following parts:

How do Organisms Reproduce Class 10 Notes | Reproduction class 10 notes | Class 10 Reproduction chapter | Notes on Reproduction class 10

Ovary

• A pair of ovaries are situated on either side of the abdomen.

• The ovaries produce the female reproductive cells, known as eggs.

• At birth, a female has thousands of immature eggs stored in the ovaries.

• With the onset of puberty, some of these eggs begin to mature.

• Every month, a mature egg is released from one of the ovaries.

(ii) Oviduct (Fallopian Tube)

• The oviduct captures the egg released by the ovary and transports it to the uterus.

• Fertilization, or the fusion of the male and female gametes, occurs in the oviduct.

(iii) Uterus

• The uterus is a sac-like organ where the development of the baby occurs.

• The uterus connects to the vagina through the cervix.

Fertilization of the Egg

• When the Egg is Fertilized

• Once the egg is fertilized, it forms a zygote, which then attaches to the uterus and starts developing into an embryo.

• The embryo receives nutrients from the mother's bloodstream through a specialized structure called the placenta. The placenta provides a large surface area for the exchange of essential substances like glucose, oxygen, and waste products.

• The duration from fertilization to the birth of the baby is known as the gestation period, which typically lasts around 9 months.

When the Egg is Not Fertilized

• Each month, the uterus gets ready to receive a fertilized egg.

• The uterine lining thickens and becomes spongy, preparing to support a developing embryo.

• If fertilization doesn't take place, the uterine lining is not required anymore.

• The lining deteriorates and is shed from the body through the vagina in the form of blood and mucus.

• This process, which occurs roughly every 28 days, is known as menstruation.

 Reproductive Health

• Reproductive health encompasses the complete well-being in all areas of reproduction, including physical, emotional, social, and behavioral aspects.

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Sexually Transmitted Diseases (STDs)

• Various diseases can be transmitted through sexual contact, such as:

  (i) Bacterial: Gonorrhea and syphilis
  (ii) Viral: Warts and HIV/AIDS

• Using condoms can help reduce the risk of these infections.

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Contraception: Contraception refers to methods used to prevent pregnancy by stopping the fertilization of the egg.

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Methods of Contraception

(i) Physical Barriers

• These methods prevent the union of sperm and egg.
• Examples include the use of condoms, cervical caps, and diaphragms.

(ii) Chemical Methods

• These include the use of oral contraceptive pills.
• These pills alter the body's hormonal balance to prevent egg release.
• However, they may have side effects.

(iii) Intrauterine Contraceptive Devices (IUCD)

• A device like Copper-T or a loop is inserted into the uterus to prevent pregnancy.

(iv) Surgical Methods

• Vasectomy: In males, the vas deferens is surgically blocked to stop sperm transfer.
• Tubectomy: In females, the fallopian tubes are blocked to prevent the egg from reaching the uterus.

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Female Foeticide

• Female foeticide refers to the illegal act of terminating a female fetus in the womb.

• For a healthy society, maintaining a balanced sex ratio is crucial. This can be achieved through education and discouraging harmful practices like female foeticide and prenatal sex determination.

• Prenatal sex determination is illegal in many countries, including ours, to ensure a balanced sex ratio.