How Do Organisms Reproduce Class 10 Notes Science ch 7

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How do Organisms Reproduce Class 10 Notes is part of Class 10 Science Notes are available for free download in PDF format. NCERT Class 10 Science Notes Chapter 7 on How do Organisms Reproduce is provided here.

NCERT Class 10 Science Notes Chapter 7 How do Organisms Reproduce

Reproduction is a fundamental process through which living organisms produce offspring of their own kind. It is essential for the survival and continuity of species.

In class 10, students learn about the various modes of reproduction in organisms. This article provides comprehensive notes on how organisms reproduce, covering both asexual and sexual reproduction methods.

Asexual Reproduction

  • A single parent is involved.
  • Gamete formation and fusion do not take place.
  • The offspring produced are nearly identical to both each other and the parent organism.
  • Asexual reproduction commonly takes place in favorable environmental conditions and when there is an ample food supply.
  • It is a quicker mode of reproduction.

Type of Asexual Reproduction

  • Binary Fission
  • Multiple Fission
  • Budding
  • Fragmentation
  • Regeneration
  • Spore Formation
  • Vegetative Propagation
  • Fragmentation

Binary Fission

Binary fission is a type of asexual reproduction commonly observed in single-celled organisms such as bacteria and protozoa. In this process, the parent organism divides into two identical daughter cells.

How Do Organisms Reproduce Class 10 Notes

Multiple Fission

Plasmodium, a malarial parasite, exhibits the formation of a thick resistant wall by the parent cell around itself, creating a cyst, during unfavorable conditions.

Within this cyst, the cytoplasm undergoes multiple divisions, resulting in the formation of numerous plasmodia.

When conditions become favorable, the cyst wall breaks, releasing the Plasmodium organisms.

How do organisms reproduce class 10 Notes science chapter 7

How Do Organisms Reproduce Class 10 Notes

Budding

Budding is a form of asexual reproduction seen in organisms like yeast and hydra. In this process, a small bud or outgrowth develops on the parent organism, eventually detaching and growing into a new individual.

How do organisms reproduce class 10 Notes science chapter 7

Spore Formation

The organisms in fungi, algae, and some plants utilize spore formation as a method of asexual reproduction.

These organisms produce specialized structures called spores, which have the ability to develop into new individuals when favorable conditions are present.

How do organisms reproduce class 10 Notes science chapter 7

Fragmentation

Organisms like flatworms and starfish actively engage in fragmentation, a type of asexual reproduction.

During this process, the parent organism actively breaks its body into multiple fragments, with each fragment having the potential to develop into a new individual.

How do organisms reproduce class 10 Notes science chapter 7

Vegetative Propagation

Plants commonly engage in vegetative propagation, an activity whereby new individuals grow from vegetative parts like stems, roots, and leaves.

Type of Vegetative Propagation

  • Natural vegetative propagation.
  • Artificial vegetative propagation

Importance of Vegetative Propagation

  • Plants have the capability to bear flowers and fruits earlier.
  • Plants, which cannot produce viable seeds, can also reproduce through vegetative propagation.
  • All plants closely resemble their parent plant genetically.
  • It is possible to obtain seedless varieties.
  • Horticulturists utilize the property of vegetative propagation to develop methods like layering and grafting in order to cultivate multiple plants such as sugarcane, roses, or grapes.
  • Tissue Culture: The technique involves developing new plants from a cell or tissue in a nutrient medium under aseptic conditions.
  • The cell or tissue is placed in a nutrient medium, leading to the formation of a mass of cells known as callus.
  • The callus is then transferred to another nutrient medium where it differentiates and gives rise to a new plant.

Regeneration

Organisms possess the ability to develop their lost parts actively. Certain organisms exhibit a high regenerative capacity, which also serves as a mode of reproduction.

Planaria, for instance, demonstrates this ability.

Specialized cells are responsible for carrying out regeneration, actively undergoing division to form a cluster of cells.

These cells then undergo specific changes to differentiate into distinct cell types and tissues, following an organized sequence referred to as development.

Tissue Culture

In tissue culture, practitioners actively develop new plants by placing a cell or tissue in a nutrient medium under aseptic conditions.

The cell or tissue forms a mass of cells known as callus within the nutrient medium. Subsequently, they transfer this callus to another nutrient medium, where it undergoes differentiation and gives rise to a new plant.

Sexual Reproduction

Plants and human beings engage in sexual reproduction, which involves two individuals of different sexes (male and female).

During sexual reproduction, the male organism with male sex organs actively produces small and motile male gametes known as sperms, while the female organism with female sex organs actively produces ova, which are generally large and store food.

The male and female gametes actively fuse together to form a zygote, which then develops into a new organism.

Significance of Sexual Reproduction :

  • In sexual reproduction, two different organisms actively utilize their DNA and cellular apparatus, contributing to the diversity of traits in their offspring.
  • The derivation of gametes from two organisms leads to the formation of a new combination of genes, thereby enhancing the likelihood of genetic variations.
  • The process of sexual reproduction gives rise to new species. It involves the division of sex organs, reducing the amount of DNA by half.
  • As a result, the zygote formed after fusion retains the same amount of DNA as its parents, ensuring the preservation of DNA within a species.

Limitation of Sexual Reproduction:

The process of sexual reproduction actively combines DNA from two different organisms, which can also introduce undesirable features.

Sexual reproduction in flowering plants

  • The flower contains the reproductive parts.
  • The sepals, petals, stamens, and carpels are the parts of the flower.
  • Green structures called sepals protect the inner parts while the flower is in the bud stage.
  • Colorful petals attract insects to facilitate pollination.
  • Stamens serve as the male reproductive parts and generate pollen grains containing male gametes. Each stamen comprises two parts:-
  • A stalk called filament and a swollen top part called anther, which holds a large number of pollen grains.

Fertilization

The process of fusion of male and female gametes to form a zygote during sexual reproduction is called fertilization. In plants, pollination precedes fertilization. The following activities occur:

Ferilization
  • Pollen tubes grow out of the pollen grains, travel through the style, and reach the ovary via the micro pyle.
  • The pollen tube contains two male germ cells, while each ovule contains two polar nuclei and a female germ cell (egg).

The pollen tube actively releases two male germ cells inside the ovule. One of the male germ cells actively fuses with the female germ cell, forming a zygote that develops into the embryo, which is the baby plant.

The fusion process in which two male germ cells actively fuse with the polar nuclei is known as triple fusion.

This results in the formation of two active fusions during fertilization in flowering plants, which are collectively called double fertilization.

Hence, the process is termed syngamy for fusion and triple fusion for the active fusion of male germ cells with the polar nuclei.

  • The ovule actively develops a tough coat and transforms into the seed.
  • The ovary actively undergoes rapid growth and matures to form a fruit.
  • Petals, sepals, stamens, style, and stigma actively wither and detach.

Human Being Reproduction

Human beings actively engage in sexual reproduction. The male parent actively produces male gametes known as sperms. Sperms, possessing tails, exhibit motility. They are produced in large quantities within the testes.

On the other hand, the female parent actively produces female gametes called ova. Ova are larger in size, non-motile, and only one ovum is produced by one ovary per month.

Sperms do not store food, whereas ova contain stored food.

Both gametes are microscopic unicellular structures and have half the number of chromosomes compared to body cells.

Human Being Reproduction

Human beings enter a phase of reproductive activity upon reaching puberty.

Puberty, occurring during adolescence, marks a decrease in the rate of general body growth and the maturation of reproductive tissues.

Males experience the onset of puberty between the ages of 11 to 13, while females experience it between the ages of 10 to 12.

Puberty encompasses various physical, mental, emotional, and psychological changes in both boys and girls, which occur gradually over time.

For instance, thick and dark hair begins to grow in new body regions such as the armpits and genital area.

Thinner hair may appear on the legs, arms, and face. The skin becomes oilier, and facial pimples may emerge. Individuals become more body-conscious, and independent, and may display increased aggression.

Male Reproductive System

The male reproductive system is a complex and fascinating part of the human body. It plays a vital role in the process of human reproduction, enabling the creation of new life.

In this article, we will explore the anatomy and functions of the male reproductive system, shedding light on its various components and their significance.

By gaining a deeper understanding of how this intricate system operates, we can appreciate its importance in the overall reproductive process.

Male Reproduction System
  • Testes come in pairs.
  • Ducts form a system.
    • Epididymis
    • Sperm duct or vas deferens exists.
    • Urethra
  • A system of glands
    • Seminal vesicles
    • Prostrate gland
    • Cowper’s gland

The scrotum, a bag-like structure, contains one pair of testes, which lie outside the abdominal cavity. This positioning is extra-abdominal. The testes need to be maintained at a temperature 1-3 degrees lower than the body to facilitate the production of functional sperms.

Functions of testes

  • Producing male gametes, i.e., sperms.
  • Producing a male reproductive hormone called testosterone, which produces sperms as well as secondary sexual characteristics in males.

The epididymis attaches to each testis, and it highly coils into a tube. It stores the sperms and facilitates their maturation.

The sperm duct or vas deferens receives each epididymis. The vas deferens ascends and enters the abdominal cavity.

It combines with the duct from the urinary bladder, forming a common duct called the urethra.

The urethra passes through the penis and has an external opening. Along the pathway, the ducts of the three glands also open and release their secretions into the vas deferens.

1. The Testes

The testes are the primary organs of the male reproductive system responsible for the production of sperm.

They are located within the scrotum, a sac-like structure outside the body, which helps regulate the temperature necessary for sperm production.

2. Epididymis

The epididymis is a coiled tube situated on the posterior side of each testis. It serves as a site for sperm maturation and storage.

Here, the sperm acquire the ability to swim and fertilize an egg.

3. Vas Deferens

The vas deferens, also known as the sperm duct, is a muscular tube that connects the epididymis to the urethra.

Its main function is to transport mature sperm from the epididymis to the urethra during ejaculation.

4. Urethra

The urethra is a tube that runs through the penis and serves as a common pathway for both urine and semen.

It carries urine from the bladder out of the body and also transports semen during ejaculation.

Female Reproductive System

The female reproductive system is an intricate and fascinating part of the human body. It plays a crucial role in the creation of life and encompasses various organs and processes that work together harmoniously.

Understanding the female reproductive system is essential for women’s health and overall well-being.

In this article, we will explore the different components of the female reproductive system, their functions, and common concerns associated with it.

Female Reproductive System class 10
  • 1 pair of ovaries
  • 1 pair of fallopian tubes or oviducts
  • A uterus/womb
  • A vagina/birth canal.

Each ovary assumes an almond shape and resides within the abdominal cavity. At birth, every girl child possesses thousands of immature ova. The maturation of these ova commences only during puberty. One ovary produces a single ovum per month, with each ovary releasing an ovum every other month. The process of the ovum being released from the ovary into the abdominal cavity is referred to as ovulation.

Functions of ovary

  • produce and release ova
  • produce female reproductive hormones: estrogen and progesterone.

Vagina

The cervix connects the uterus to the vagina, which is a muscular tube responsible for delivering the baby after nine months.

Additionally, the vagina acts as the canal for receiving semen during copulation.

During copulation, the male discharges semen into the vaginal tract.

The sperms travel upward and reach the fallopian tube, where one sperm fuses with the ovum to form the zygote.

As the zygote descends into the uterus, it undergoes division and further multiplication. The embryo then implants itself into the thickened endometrium.

To obtain nutrition, the embryo relies on the mother’s blood facilitated by the placenta, a disk-like structure embedded in the uterine wall.

The placenta features finger-like villi on the embryo’s side, while blood spaces surround the villi on the mother’s side.

The villi provide an extensive surface area for the exchange of glucose, oxygen, and waste materials between the mother and the developing embryo.

When the embryo reaches a stage resembling a human, it is referred to as a fetus.

The fetus continues to develop inside the uterus for approximately nine months until rhythmic contractions of the uterine muscles lead to the delivery of the baby.

Menstruation

The female actively expels the loss of blood, mucous, unfertilized ovum, and the ruptured cells and tissues of the endometrium through her vagina. This occurs in every reproductively active female (from puberty) in a 28-day cycle.

The flow of blood lasts for 2 to 8 days. If fertilization does not occur, the endometrium sheds, resulting in the loss of blood and mucous through the vagina.

If fertilization occurs, the endometrium thickens and becomes spongy to nourish the embryo, preventing menstruation.

A woman with a developing embryo in her womb is considered pregnant. The onset of menstruation at puberty is called menarche.

The cessation of menstruation between the ages of 45 and 55 is referred to as menopause.

Reproductive Health

Sexually transmitted diseases and birth control.

Engaging in sexual intercourse with an infected partner can lead to the occurrence of several diseases.

These diseases, commonly referred to as sexually transmitted diseases (STDs), can be caused by bacteria, such as syphilis and gonorrhea, or by viruses, including HIV-AIDS and warts.

To prevent the transmission of these diseases, individuals can take proactive measures by utilizing birth control methods, such as using a condom during sexual activity.

Mechanical methods

These methods actively prevent the passage of semen to the fallopian tube:

(i) Using condoms: Individuals wear thin rubber tubes called condoms over the penis before engaging in sexual intercourse. Condoms collect the semen, preventing its discharge into the vagina.

(ii) Placing a diaphragm: A doctor fixes a thin rubber diaphragm onto a flexible metal ring, which is then fitted over the cervix in a woman’s body.

(iii) Inserting an Intra Uterine Contraceptive Device (IUCD) or loop: Medical professionals insert this device into the uterus, where its insertion triggers the secretion of certain substances that prevent the embryo’s implantation in the uterine wall. Both methods (ii) and (iii) have associated side effects.

Chemical methods

  • People use spermicides, which are strong sperm-killing chemicals available in the form of creams, jellies, etc., to inject into the vagina just before copulation.
  • People take oral contraceptive pills, which are hormonal pills that prevent ovulation but do not stop menstruation.

Surgical methods

  • Vasectomy: Males undergo the activity of cutting and ligating the vas deferens.
  • Tubectomy: Females undergo the activity of cutting and ligating the fallopian tubes.
  • Medical termination of pregnancy (MTP) or abortions involve the activity of eliminating the developing embryo. However, this practice can be misused for female foeticide, which involves the killing of the female foetus. It is important to avoid this practice as it disturbs the male-female ratio in a population.

Comparison of Asexual and Sexual Reproduction

Asexual and sexual reproduction have distinct advantages and disadvantages:

Advantages of Asexual Reproduction

  • Rapid reproduction and population growth
  • No need for a partner or mate
  • Offspring are genetically identical to the parent
  • Suitable for stable environments

Advantages of Sexual Reproduction

  • Genetic variation among offspring
  • Enhanced adaptability to changing environments
  • Repair of damaged DNA through recombination
  • Evolutionary advantage

Disadvantages of Asexual Reproduction

  • Lack of genetic diversity
  • Vulnerability to environmental changes
  • Accumulation of harmful mutations
  • Limited scope for adaptation

Disadvantages of Sexual Reproduction

  • Dependence on finding a mate
  • Time and energy investment in finding a partner
  • Risk of sexually transmitted diseases
  • Reduced population growth rate

Class 10 Science Notes List

Chapter of class 10 science basically includes some important Chapter topics from the NCERT Book, Such as acids bases and salts, metals and non-metals, chemical reactions and equations, Carbon and its Compounds, Life Processes, Control, and Coordination, etc.

Chapter-wise notes on these subjects are available in the table below, click on the links to access them.

FAQ’s How do organisms reproduce class 10 notes

1. How do organisms reproduce without a mate?

Some organisms reproduce asexually through methods such as binary fission, budding, spore formation, and fragmentation. These processes do not require a mate for reproduction.

2. Can plants reproduce both sexually and asexually?

Yes, plants have the ability to reproduce both sexually and asexually. Sexual reproduction in plants involves pollination and fertilization, while asexual reproduction occurs through methods like vegetative propagation and tissue culture.

3. What is the purpose of sexual reproduction?

Sexual reproduction introduces genetic variation among offspring, which enhances adaptability and promotes evolutionary advantage. It also allows for the repair of damaged DNA through recombination.

4. How does the menstrual cycle work?

The menstrual cycle is a series of hormonal changes in females that prepares the uterus for potential pregnancy. It involves the shedding of the uterine lining, followed by the growth of a new lining in preparation for fertilization.

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