CBSE Class 10 Chapter-7 How Organisms Reproduce: In the Organisms Reproduce chapter, we will learn the ability of organisms to produce offspring and carry out the next generation. Organisms reproduce in two ways asexual reproduction and sexual reproduction. Asexual is the mode of reproduction in which the production of the individual from a single parent takes place and sexual reproduction is the mode of reproduction in which the production of individuals from both parents.

How does an Organism Reproduce?

Reproduction is the process in which the production of offspring takes place and is also a biological process in which organisms give rise to offspring. 

The organism reproduces in two ways those are: 

• Asexual Reproduction 
• Sexual Reproduction

Asexual Reproduction

Asexual Reproduction is the mode of reproduction in which the production of the individual from a single parent takes place. They are identically and genetically similar. In this process, the fusion of gametes does not take place. The gametes are not formed. it is extremely used as a means of rapid multiplications. Mostly it is present in lower animals and plants.

Asexual Reproduction can be further divided into:

Fission

 

It is defined as the splitting of unicellular organisms into two or more daughter cells. Many protozoa and bacteria simply divide into two halves during cells. In organisms such as amoeba the splitting of the parent cell into an equal half of the daughter cell, it can take place at any place.

• Binary fission: It is an asexual reproduction in which organisms duplicate their genetic material and divide into two parts (cytokinesis) and form new daughter cells.
• Multiple fission: It is an asexual reproduction in which organisms divide themselves into more than two daughter cells and the nucleus repeatedly divided and form a large no of nuclei.

Fragmentation 

Fragmentation is the process through which an organism fragments into various parts.

This is not true for all multi-cellular organisms. They are unable to simply divide cells at a time. Because many multicellular organisms, as we have shown, are not just a collection of random cells, this is the case. Specialized cells are arranged into tissues, and tissues are arranged into organs, which must then be positioned in specific locations throughout the body.

Regeneration

The process through which plants and animals naturally replace or recover lost or damaged cells, tissues, organs, and even complete body parts to their original state.

Many fully differentiated creatures can produce new individuals from their constituent components. In other words, if the person is chopped or divided into many pieces, many of these bits will grow. into distinct people. Simple organisms like Hydra and Planaria, for instance, can be divided into countless pieces, and each one develops into a full organism. 

Budding 

 

A type of asexual reproduction wherein the generative anatomical point of the parent organism serves as the foundation for the development of the young individual. Some species allow buds to grow practically anywhere on the body. organisms like Hydra use regenerative cells in the process of reproduction budding. A Hydra bud forms as an outgrowth as a result of recurrent cell division at one particular point.  When completely grown, these buds separate from the parent body and grow into new, independent individuals. They start as tiny individuals.

Vegetative Propagation 

 

Vegetative propagation is the process of creating new plants from the older, non-reproductive portions of an existing plant, such as roots, shoots, and leaves. Many plants have elements including the root, stem, and leaves that, under the right circumstances, sprout new plants. 

In many plants, new plants develop from develops from vegetative parts such as 

• By roots- sweet potato 
• By steam-potato 
• By leaves -podophyllum  

Tissue Culture

A method of biological research in which fragments of tissue from an animal or plant are transferred to an artificial environment in which they can continue to survive and function. Tissue or cells from a plant’s growing tip are removed in tissue culture to create new plants. After being placed in an artificial medium, the cells quickly divide to create a tiny cluster of cells or calluses. The callus is moved from another environment that contains hormones for differentiation and growth. 

Spore Formation 

It is possible to identify individual reproductive components in many basic multicellular organisms. The hyphae of the bread mold (Rhizopus) are the thread-like structures that formed on the bread. They do not serve as reproductive organs. The microscopic blob-on-a-stick formations, on the other hand, are engaged in reproduction. In the blobs, which are called sporangia, are cells, or spores, that may one day grow into fresh Rhizopus individuals. The spores are protected by strong walls that keep them from growing until they encounter another damp surface.

Also Read: Types of Asexual Reproduction

Sexual Reproduction

Sexual Reproduction is the mode of reproduction in which the production of individuals from both parents. In this process the fusion of gametes takes place. The gametes are formed. It involves a complex life cycle in which a gamete (haploids such as sperm or egg) fuse with another gamete and formed a zygote.

It is a natural reproduction method by which all multicellular organisms reproduce. DNA and cellular components must be copied to divide into two new cells from one. As we have learned, errors can occur throughout the DNA copying process, and these errors are what cause variances in creature populations. Variations cannot safeguard each creature, but in a population, they help guarantee the survival of the species. Therefore, it would make sense if organisms devised reproductive strategies that permitted an increasing amount of variety to be produced.

Although DNA-copying mechanisms are not 100% exact, they are accurate enough to make the process of variety formation fairly sluggish. Many of the resulting DNA copies would be inaccurate if the DNA copying mechanisms were to become less precise.

The importance of Variation 

Variation can be defined as the variation in DNA sequences. It makes one organism different from the other organism. Variations in a species of an organism help to adapt to the environment, it also prevents the extinction of a species. Modes of reproduction are used by single organisms.

Also Read: Importance of Variation 

Sexual Reproduction Plant 

Flowers are reproductive parts of plants. A typical flower consists mainly of four parts– sepals, petals, stamens, and pistils.

Types of Flowers 

1. Bisexual flower -The flower that has both male and female reproductive organs is known as a bisexual flower because it has both stamens and carpels. The hibiscus, lily, mustard, rose, and sunflower is some examples of bisexual flowers.
2. Unisexual flower-Unisexual flowers are those that only include stamens or carpels, the male or female reproductive organs. Cucumber, papaya, pumpkin, and bitter gourd are some examples of unisexual flowers.

Process of Sexual Reproduction in Plants 

 

1. The stigma is located at the end of the style and may be sticky. The ovary is located at the bottom, where it is enlarged. Ovules are found in the ovary, and each ovule contains an egg cell. male sperm cells.
2. pollen grain unites with the female gamete inside the ovule to form. The zygote that results from the union of the germ cells, or fertilization, can develop into a new plant.
3. Therefore, the pollen must be moved from the stamen to the stigma. Self-pollination is the term used to describe this pollen transfer when it takes place within the same flower. On the other hand, cross-pollination refers to the transfer of pollen from one flower to another. This pollen exchange from one.
4. Zygote divides from the embryo. Ovule develops a thick coat and changes into seeds gradually.
5. The ovary changes into fruit and other parts of the flower fall off.
6. The seed germinates to form a plant under suitable conditions such as air, moisture, etc.

Also Read: Cross-Pollination and Self Pollination

Reproduction in Humans 

Humans use a sexual mode of reproduction to reproduce. In humans, the male reproductive system includes the testes, which produce sperm, and the penis, which is used to deliver sperm to the female reproductive system during sexual intercourse. The female reproductive system includes the ovaries, which produce eggs, and the uterus, where the fertilized egg implants and develops into a fetus. Sexual maturation is the period of life when the production of germ cells i.e. ova (female)and sperm (male) starts in the body. This period of sexual maturation is called puberty.

Changes at Puberty

Following are the changes that occurred during puberty: 

• Common in male and female 
  • Thick hair growth in armpits and genital area.
  • Skin becomes oily, which may result in pimples.
• In girls 
  • Breast size begins to increase. 
  • Girls begin to menstruate.
• In boys 
  • Thick hair growth on the face.
  • The voice begins to crack 

Male Reproductive System 

 

The male reproductive system consists of two portions one that produces germ cells and the other that delivers the germ cell to the site of fertilization. The human male reproductive systems consist of the following organs:- 

• Testes: 
  • A pair of tests are located inside the scrotum which is present outside the abdominal cavity.
  • The scrotum has a relatively lower temperature needed for the production of sperm.
  • Male germ cells i.e., sperms are formed here. 
  • Testes release the male sex hormone (testosterone)
  • The function of testes:
    • Regular production of sperm.
    • Bring changes at puberty.
• Vas Deferens: It passes sperm from tests up to the urethra.
• Urethra: 
  • Seminal vesicles and prostate gland add their secretion to the sperms. This fluid provides nourishment to sperm and makes their transport easy.
  • Sperm along with the secretion of glands from semen.

Female Reproductive System

 

Female Reproductive System is the complex structure of organs which work together to produce offspring. Ovary,Fallopian tube, Uterus, Cervix and Vagina are included in the female reproductive system. The ovaries are the two small, almond-shaped glands located on either side of the pelvis, which produce and release eggs (ova) during the menstrual cycle. The fallopian tubes are thin, muscular tubes that extend from the ovaries to the uterus, and are the site where fertilization occurs if sperm are present.

The uterus, is a muscular organ where a fertilized egg implants and grows during pregnancy. The cervix is the narrow, lower end of the uterus that protrudes into the vagina. It produces mucus that helps sperm move through the reproductive tract. The vagina is the muscular tube that extends from the cervix to the external genitalia. It is the site where sperm are deposited during intercourse and serves as the birth canal during delivery.

Reproductive Health

Reproductive health means total well-being in all aspects of reproduction i.e. physical emotional, social, and behavioral. As we’ve seen, sexual maturation occurs gradually over a period when the body’s basic growth is still occurring. Therefore, a certain level of sexual development does not imply that the body or the mind is prepared for having sex or for having and raising children.
How can we tell if the body or the mind is prepared for such a weighty task? We are all facing a variety of stresses related to these challenges. Whether we want to or not, we may feel pressure from our friends to take part in a variety of activities. 

FAQs on How Organisms Reproduce?

Q1: Difference between binary fission and multiple fission?

Answer:

In binary fission, the cell divides into two daughter cells whereas in multiple fission the dived daughter cell more cell two

Q2: Define reproduction. 

Answer:

Reproduction is the process in which the production of offspring takes place and is also a biological process in which organisms give rise to offspring.

Q3: Name two simple organisms having the ability to regenerate?

Answer:

Hydra and Planaria are two organisms that have the ability to regenerate.

Q4: List four modes of asexual reproduction.

Answer:

The four modes of asexual reproduction are :

• Binary fission
• Budding
• Regeneration 
• Vegetative propagation.