CBSE Class 10 Science Chapter 8 How Do Organisms Reproduce Notes:Download PDF
All living organisms multiply or reproduce and produce offspring of a similar kind. Reproduction is an essential process for the existence of a species and the continuation of life.
Here, in this chapter, we will learn about how different unicellular and multicellular organisms such as bacteria, algae, plants, animals and human beings reproduce. What are the different reproductive structures and modes of reproduction such as cell division, vegetative reproduction, asexual reproduction, and sexual reproduction.
Watch the video below to learn about how organisms reproduce:
Reproduction is the process by which all organisms multiply in number and increase their population.
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Asexual reproduction is a method of reproduction that involves only one organism. A single organism reproduces two or multiple organisms on its own. This is seen in all unicellular organisms, some multicellular organisms and a few plants.
For More Information On Plant Reproduction, Watch The Below Video:
To know more about Asexual reproduction, visit here.
The mode of reproduction that involves two individuals; one male and one female. They produce sex cells or gametes which fuse to form a new organism.
To know more about Sexual reproduction, visit here.
- Fission is an asexual reproduction that is common in most of the unicellular organisms.
- When the fission results in two daughter cells, it is binary fission (e.g. paramecium).
- When fission results in many daughter cells, it is called multiple fission (e.g. Plasmodium).
- Planes of fission may be different for different organisms.
To know more about Binary Fission, visit here.
- Budding is a type of asexual reproduction in which a small cyst-like structure is formed on the parent’s body, which gives rise to a new individual.
- Bud may remain attached to the parent (yeast) or may separate and become a new individual (hydra).
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Regeneration and fragmentation
- Regeneration is the process of growing back the lost organ or body part by the organism (e.g. lizard).
- Fragmentation is the process by which an organism gets fragmented into smaller pieces and each piece grows into a whole new organism.
- E.g. Planaria, Hydra
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Organisms such as fungi make spores that can grow into complete new individuals when dispersed from their fruiting body. Spores are produced inside sporangia. They are covered by a thick outer layer that protects them in adverse conditions. When spores get suitable environmental conditions they germinate and begin to grow.
Read more: Spore Formation
- This is atype of asexual reproduction seen in plants.
- The vegetative part of the plant,like leaves, stem, roots, gives rise to a new plant.
- Vegetative propagation can be artificial or natural.
- Natural vegetative propagation happens through leaves (e.g. bryophyllum), stem (e.g. turmeric, ginger), runners/stolon (e.g.grass runners, strawberry), bulbs ( e.g. onion, lily), etc.
- Artificial methods include cutting, grafting, layering and plant tissue culture.
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Types of Cell division
Two types of cell division are seen in eukaryotic organisms:
- Requiredforasexualreproduction,developmentandgrowth,cellreplacementand regeneration
- Requiredforsexualreproduction, i.egamete formation
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The Reproductive System
In humans, there is a remarkable difference in the male and female reproductive systems. Testes are the main reproductive structure in males where sperms (male gametes) are produced and ovum (female gamete) is produced inside the ovary. Let us now learn in detail about male and female reproductive systems in humans.
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Male reproductive system
- The main reproductive organ in males is a pair of testes.
- They produce the male sex cells called sperms and also produce the male sex hormone testosterone.
Male main reproductive organs
- The main reproductive organ in males is a pair of testes.
- They are present in scrotal sacs outside the body and contain seminiferous tubules as the structural and functional unit.
- Male sex cells, sperms, are produced by seminiferous tubules and mature in the epididymis.
- Leydig cells or interstitial cells present in between the seminiferous tubules secrete hormone testosterone.
Male accessory reproductive organs
- Several accessory reproductive organs aid in the reproductive process.
- The prostate gland and the seminal vesicles are glands of the reproductive system which make semen and nourish the sperm.
- Penis, having urethra passing through it, is called copulatory organ.
- In males, the vas deferens and the urethra are the main ducts.
- A single vas deferens carries sperms from respective testis up to the urethra.
- The urethra acts as a common passage for semen and urine.
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Female reproductive system
The human female reproductive system consists of a pair of ovaries, a pair of fallopian tubes/oviducts and the accessory organs such as the uterus and the vagina.
Female main reproductive organ
- The main reproductive organ in afemale is apair of ovaries.
- They produce the female sex cells called eggs or ova and also produce female sex hormones called estrogen and progesterone.
Female accessory reproductive organ
- Uterus, oviducts, and vagina are the accessory reproductive organs in human females.
- The uterus is the site of fetal development and the vagina receives sperm from the male. Ovum is carried from ovaries to the uterus through a pair of oviducts.
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- Menstruation is the cyclic event of the release of the ovum from the ovary and its removal from the body when fertilization does not happen.
- During menstruation, the blood-rich endometrium of the uterus also breaks down while the ovum is removed from the body.
- Two pituitary hormones, LH and FSH, and two ovarian hormones, estrogen and progesterone, all have their roles in menstruation.
- In humans, the cycle repeats every 28 days.
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Humans reproduce sexually. The male produces sperms and the female produces eggs. When the sperm fuses with the egg, it forms a zygote that gives rise to a new progeny.
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Reproductive health deals with the prevention of STDs and unwanted pregnancy. Understanding the reproductive system is also a part of reproductive health awareness.
- Contraceptives are devices that prevent unwanted pregnancy and help avoid STDs.
- Contraceptives can be of various types such as mechanical barriers, hormonal/chemical methods, surgical methods, etc.
- It is a very unreliable contraceptive method where the coitus is stopped before the male ejaculates inside the female reproductive tracts.
- Another unreliable method of contraception is where coitus is avoided when the female is fertile and the chances of fertilization are very high.
- One of the most effective methods of contraception.
- A mechanical barrier that stops the semen from entering the female tract preventing pregnancy.
- It also avoids the possibility of contracting STDs.
- Diaphragms are barriers that can be added inside the female reproductive tracts.
- They stop the entry of semen inside the female tract and thus prevent pregnancy.
- Contraceptive pills are chemical methods of contraception.
- They change the level of hormones in the body that prevents the release of the ovum from the ovaries.
- Emergency pills are those pills which can be taken after coitus to avoid pregnancy.
- They quickly change the level of hormones in the body and prevent a successful implantation even if the egg gets fertilized.
- IUD stands for Intrauterine Device.
- They can be used for a couple of years.
- It is a device that is inserted into the uterus, changing its shape and preventing successful implantation of the zygote.
- Sterilization is a surgical method of going permanently sterile.
- This can be done in both males and females.
- In males, it is called vasectomy and in females, it is called tubal ligation.
To know more about Contraceptive Methods, visit here.
Reproduction in Plants
Plants reproduce by both, asexual and sexual methods. Vegetative propagation is a type of asexual reproduction in plants. Let’s learn now about sexual reproduction in plants.
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Sexual reproduction in flowering plants
- Sexual reproduction in plants happens through flowers.
- Essential whorls of the flowers such as androecium and gynoecium help in the sexual reproduction of plants.
Read more: Sexual Reproduction in Plants
Non-essential parts of flowers
- The typical structure of flowers contains essential whorls and non-essential whorls.
- Sepals and Petals are called non-essential whorls as they do not directly take part in reproduction.
- Sepalsprotect the inner delicate whorl during bud condition and also perform photosynthesis if they are green in colour.
- Petals, when they are coloured, attract insects for pollination.
Essential whorls of flowers
- Androecium and gynoecium are called as essential/reproductive whorls of a flower.
- Androecium produces pollen grains containing male gametes and gynoecium produces ovules which are female gametes.
- Bisexual flowers contain both the whorls while unisexual flowers contain either of them.
- Each individual member of androecium is called astamen and consists of antherand filament.
- Anther produces haploid pollen grains.
- Each individual member of gynoecium is calledpistil and consists of stigma, style and ovary.
The process of transfer of pollen grains from anthers to the stigma of a flower is known as pollination.
- It is required for fertilization.
- Pollination has two types, self-pollination(autogamy) and cross-pollination (allogamy).
- In self-pollination, the transfer of pollen grains takes place from anthers to the stigma of the same flower or another flower of the same plant.
- In cross-pollination, pollens are transferred from anthers to the stigma of another flower.
- Many pollinating agents play their roles in cross-pollination. Examples: water, wind, insects, birds, bats, etc.
Know more: Pollination
Fusion of male and female gametes is known as fertilization.
- In flowering plants after pollination, the pollens germinate on the stigma surface of pistil and generate two male nuclei.
- Ovule has egg cell and two polar nuclei.
- One male nucleus fuses with two polar nuclei and forms triploid endosperm.
- Another male nucleus fuses with the egg cell and forms the zygote that gives rise to the embryo and future plant.
- After fertilization, ovary becomes fruit and ovules turn into seeds. All other parts wither away.
Know more: Fertilisation in Plants
Watch the video below to learn more about Sexual Reproduction in Flowering Plants(Structure of Flower & Pollination):
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Frequently Asked Questions on CBSE Class 10 Science Notes Chapter 8: How do Organisms Reproduce
What is difference between fission and fusion?
Fission is the process where an atom splits into two or more smaller parts. Whereas fusion involves the fusing of two or smaller atoms into a larger particular.
What is fragmentation?
Fragmentation is a form of asexual reproduction where the parent organism breaks into fragments. Each of these fragments are capable of growing independently into a new organism.
What is a gamete cell?
Gamete cell are the reproductive cells of an organism. Female gametes are referred to a ova or egg cells and male gametes are known as sperms.
Organisms reproduce in two ways- asexually and sexually. Asexual reproduction does not involve the fusion of male and female gametes. This takes place in bacteria, amoeba, hydra, etc. Sexual reproduction involves the fusion of male and female gametes and can be seen in humans and many animals.How do organisms reproduce question answers? ›
Solution: The different modes of reproduction in unicellular organisms are fission, budding, etc. Here, the cell divides into two daughter cells and this process of cell division continues. Whereas, in multicellular organisms there is a different organ system for reproduction.How do organisms reproduce Ncert answers? ›
There is no separate tissue for reproduction. So, they can reproduce by the process of fission or budding. Multicellular organisms contain various cells and have separate system for reproduction. So, they can reproduce by both sexual and asexual methods.How do organisms reproduce 10 notes Learnfatafat? ›
How do Organisms Reproduce? Class 10 Science Notes.
|Asexual Reproduction||Sexual Reproduction|
|Is a Fast process||Is a Slow process|
|E.g Reproduction in Hydra, Bryophyllum, etc.||E.g. Reproduction in human being, animals, flowering plants etc.|
The modes of reproduction in unicellular organisms can be fission, budding, etc. whereas in multicellular organisms, specialised reproductive organs are present. Therefore, they can Aakash Institute reproduce by complex reproductive methods such as vegetative propagation, spore formation, etc.What is spore formation? ›
Spore Formation is an Asexual Reproduction technique. Many Spores are housed in sacs known as Sporangia. The plants produce hundreds of spores and the spore sac bursts. These spores are dispersed into the air, where they germinate and create a new plant under favourable conditions.What is variation important? ›
It helps a species to survive,it also helps us to determine who is who,it helps organisms to adapt to their environment as well as to changes which do occur in the environment,however it also helps a species to emerge strong if favoured by natural selection.What is cellular fission? ›
binary fission, asexual reproduction by a separation of the body into two new bodies. In the process of binary fission, an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.What is the importance of DNA copying? ›
It ensures that each daughter cell produced at the end of cell division receives an identical amount of DNA. It causes evolution by generating variety during sexual reproduction. It aids the transmission of information or traits from parents to children.What is variation class 10? ›
Variation can be defined as any difference between the individuals in a species or groups of organisms of any species. The mutation is the ultimate source of genetic variation, but mechanisms such as sexual reproduction and gene flow contribute to it as well.
In binary fission, the parent cell is divided into two daughter cells. In multiple fissions, the parent cell is divided into many daughter cells.
Solution : DNA copying is necessary during reproduction because it leads to the transmission of characters during from parents to offsprings and variations.How do organisms reproduce extra question? ›
Fission, budding, spore formation and vegetative propagation are some of the types of asexual propagation. This method of reproduction involves two parents. It requires the fusion of gametes of both the sexes of the species. Almost all animals and higher forms of plants reproduce by this method.How do organisms reproduce KCB Solutions? ›
In Unicellular organisms reproduction takes place by fission, and budding etc. In multicellular organisms reproduction takes place by regeneration budding and vegetative propagation, spore formation and sexual reproduction.How do organisms reproduce Class 10 notes point wise? ›
During sexual reproduction, male organism having male sex organs produces male gametes i.e. sperms which are small and motile and the female organism having female sex organs produces ova which are generally large and store food. Male and female gametes fuse to form a zygote that grows into a new organism.Why do organisms take food? ›
Solution 1 : Food is needed by all organisms for many purposes: The main function of food is to help in growth. Food provides energy for movement such as running, walking or raising our arms. Food is also needed for replacement and repairing damaged parts of the body.What is the result of reproduction? ›
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction.Do spores divide? ›
Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which eventually goes on to produce gametes. Two gametes fuse to form a zygote which develops into a new sporophyte. This cycle is known as alternation of generations.What are spores function? ›
A spore is a cell that certain fungi, plants (moss, ferns), and bacteria produce. Spores are involved in reproduction. Certain bacteria make spores as a way to defend themselves.What is asexual spore? ›
3.1 Asexual spores. Asexual spores are formed after mitosis (mitospores) without the involvement of meiosis. Fungi produce an enormous variety of asexual spores. Some species can produce several types of such spores.
Genetic variation - these are differences between individuals that are inherited from parents, such as the colour of your eyes, hair and skin. Environmental variation - these are differences between individuals that are not inherited but caused by the environment that the organism lives in, including scars and tattoos.Why is variation an advantage? ›
Advantage of Variation
The advantage of having variation within a population is that some individuals will be better adapted to their environment than others. Those individuals who are not well adapted to their environment are less likely to survive and reproduce.
Genetic variation is advantageous to a population because it enables some individuals to adapt to the environment while maintaining the survival of the population.How is binary fission different from mitosis and meiosis? ›
Binary fission and mitosis are types of asexual reproduction in which the parent cell divides to form two identical daughter cells. Meiosis, on the other hand, is a form of sexual reproduction in which a cell divides its genetic material between the two daughter cells.How are binary fission and mitosis similar and different? ›
2)Both mitosis and binary fission are similar because they both are involved in the division of cells but in mitosis, cell division helps only in the growth of the organism or replacement of cells but binary fission is not only the growth of the organism but it is the process by which the organism reproduces and ...What uses binary fission? ›
Binary fission is the process of one cell simply dividing into two. It is most commonly used in archaea and bacteria, which are both prokaryotic organisms. But, it is also used in some eukaryotic protists. Binary fission is a type of asexual reproduction, where the offspring are genetic clones of the parents.What are the 4 steps of DNA replication? ›
- Step 1: Replication Fork Formation. Before DNA can be replicated, the double stranded molecule must be “unzipped” into two single strands. ...
- Step 2: Primer Binding. The leading strand is the simplest to replicate. ...
- Step 3: Elongation. ...
- Step 4: Termination.
DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. Replication is an essential process because, whenever a cell divides, the two new daughter cells must contain the same genetic information, or DNA, as the parent cell.What is importance of DNA? ›
In all living things, DNA is essential for inheritance, coding for proteins, and providing instructions for life and its processes. DNA dictates how a human or animal develops and reproduces, and eventually dies. Human cells normally contain 23 pairs of chromosomes, for a total of 46 chromosomes in each cell.Where is a gene? ›
Genes are found on tiny spaghetti-like structures called chromosomes (say: KRO-moh-somes). And chromosomes are found inside cells. Your body is made of billions of cells. Cells are the very small units that make up all living things.
F1 generation is the first filial generation, whereas F2 generation is the second filial generation obtained by crossing the F1 generation.What is called variation? ›
The differences in characteristics between individuals of the same species is called variation . Some variation is passed on from parents to offspring, via genes during reproduction. This is inherited variation. Some variation is the result of differences in the surroundings, or what an individual does.What is multiple fission explain the process by taking example of amoeba and Plasmodium? ›
MULTIPLE FISSION: In this type of fission parental body divides into many cells during unfavourable conditions. Plasmodium, amoeba etc. In this a protective resistant cyst is formed. Inside the cyst nucleus divides repeatedly to form several daughter nuclei. Each nucleus gets surrounded by a small amount of cytoplasm.How does binary fission differ from multiple fission Brainly? ›
Binary fission is a method of asexual reproduction involving the separation of the parent body into two new bodies. Multiple fission is a form of asexual reproduction in which many daughter cells are produced from a single mother cell.Which type of cell division takes place in asexual reproduction? ›
Equational division or mitosis is the type of cell division that is associated with the asexual mode of reproduction.How is the amount of DNA maintained in each generation? ›
The amount of DNA is maintained in each generation by a specialized mode of cell division called meiosis which produces specialized male and female germ cells called gametes which are haploid. One male and female gamete fertilize to give rise to a diploid zygote which has the same chromosome number as the parent.What is the importance of DNA copying in reproduction Why is variation beneficial? ›
DNA copying is an important phenomenon of reproduction through which the organisms pass on their characteristics to their offspring. It maintains the characteristics in different generations of the species. It also produces variations which are useful for the survival of species for long time.How does reproduction help in providing stability to population of species? ›
Reproduction is the process of producing new individuals of the same species by existing organisms of a species, so, it helps in providing stability to population of species by giving birth to new individuals as the rate of birth must be at par with the rate of death to provide stability to population of a species.Why do organisms reproduce class 10th? ›
Reproduction is necessary for living things because it enables them to create offspring and continue their population. Through reproduction, they pass on their genetic information to the next generation. This ensures that their species continues to exist on Earth that is why the organism reproduces.How do organisms reproduce important points? ›
SEXUAL REPRODUCTION :
The motile germ-cell fptrUeh or sperm) is called the male gamete and germ-cell containing stored food (egg or ovum) is called the female gamete. The process of fusion of two gametes is called fertilization. After fertilization, a zygote is formed , which develops into a new organism.
They are:- fission, budding, regeneration, fragmentation, spore formation, vegetative propagation etc. 5. i) Fission :- Fission is an asexual reproduction by which a unicellular organism divides and forms two or more new individuals. Fission is of two types.How do organisms reproduce extra question? ›
Fission, budding, spore formation and vegetative propagation are some of the types of asexual propagation. This method of reproduction involves two parents. It requires the fusion of gametes of both the sexes of the species. Almost all animals and higher forms of plants reproduce by this method.What are the two types of reproduction? ›
There are two types of reproduction: asexual and sexual reproduction. Though asexual reproduction is faster and more energy efficient, sexual reproduction better promotes genetic diversity through new combinations of alleles during meiosis and fertilization.Why do organisms take food? ›
Solution 1 : Food is needed by all organisms for many purposes: The main function of food is to help in growth. Food provides energy for movement such as running, walking or raising our arms. Food is also needed for replacement and repairing damaged parts of the body.What is binary and multiple fission? ›
Binary fission is the process when a parent cell divides into 2 daughter cells. Multiple fission is the process when a single parent cell divides into many daughter cells. Binary fission. Multiple fission. A parent cell is present which on cytokinesis forms 2 daughter cells.What is the result of reproduction? ›
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction.What is cellular fission? ›
binary fission, asexual reproduction by a separation of the body into two new bodies. In the process of binary fission, an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.How is reproduction achieved from a single cell type? ›
How is reproduction to be achieved from a single cell type, if the organism itself consists of many cell types? The answer is that there must be a single cell type in the organism that is capable of growing, proliferating and making other cell types under the right circumstances.What is reproduce in biology? ›
Reproduction is the production of offspring. There are two main forms: sexual and asexual reproduction. In sexual reproduction, an organism combines the genetic information from each of its parents and is genetically unique. In asexual reproduction, one parent copies itself to form a genetically identical offspring.What is the importance of DNA copying in reproduction? ›
The copying of DNA during reproduction is important because: The replication of DNA ensures that each daughter cell formed at the end of cell division, receives equal amount of DNA. If DNA won't be copied then the daughter cells won't receive all necessary genes.
It ensures that each daughter cell produced at the end of cell division receives an identical amount of DNA. It causes evolution by generating variety during sexual reproduction. It aids the transmission of information or traits from parents to children.What is DNA copying class 10th? ›
DNA copying is otherwise known as DNA replication which is the process of producing 2 identical copies of DNA from one original DNA molecule during cell division. DNA copying is important because it generates variation during sexual reproduction which leads to evolution.What is vegetative propagation write the names of any two plants grown by this method? ›
The process in which new plants are grown from the old parts of another plant like roots, shoots and leaves, without involving any reproductive organ, is termed as vegetative propagation. For example, guava trees can be propagated using their roots, and Bryophyllum can be propagated by using its leaves.