NCERT Solutions for Class 10 Science Chapter 8 How do Organisms Reproduce?
NCERT solutions for class 10 science chapter 8 How do Organisms Reproduce? Reproduction, unlike other life processes, is not essential to maintain the life of an individual organism. This fact is presented and explained with the help of CBSE NCERT solutions for class 10 science chapter 8 how do organisms reproduce. Reproduction involves the creation of a DNA copy and additional cellular apparatus by the cell involved in the process. In this chapter, you are going to study broadly three topics:
- Do organisms create exact copies of themselves
- Modes of reproduction used by single organisms
- Sexual and asexual reproduction
You will find the answers to for all the exercises and topic wise questions mentioned in the NCERT book in the given solutions of NCERT for class 10 science chapter 8 how do organisms reproduce. NCERT solutions are easy to check answers for all questions in the textbook. Various organisms use different modes of reproduction depending on their body design. Also, in fission, many bacteria and protozoa simply divide into two or more daughter cells and organisms such as hydra can regenerate if they are broken into pieces. Such facts with a lot of examples are given in NCERT solutions for class 10 science chapter 8 how do organisms reproduce. In the later half of the chapter, you are also going to study about sexual and asexual reproduction in humans and plants and also about the changes that happen during the inception of reproduction. These are again, very interesting topics and you can rather relate them to your own life in order to understand them better.
What can be the possible types of questions and their weightage asked from class 10 science chapter 8 how do organisms reproduce in board exams?
Questions asked in class 10 CBSE science board exam consist of very short answers, short answers, long answers and practical based ones which fetch 1 mark to 5 marks. This chapter carries a weightage of 8-10 marks in the CBSE board exam. NCERT solutions for class 10 science chapter 8 how do organisms reproduce will help you get those 8-10 marks in your board exams if you go through them thoroughly.
Solutions of NCERT class 10 science chapter 8 how do organisms reproduce topic 8.1 Do organisms create exact copies of themselves:
Q. 1. What is the importance of DNA copying in reproduction?
Answer:
Importance of DNA copying in reproduction-
- It keeps the characteristics of the parent species
- the characteristics and features are transferred to their progeny
- It produces variation in an organism which is the basis of the evolution of new species
Q. 2. Why is variation beneficial to the species but not necessarily for the individual?
Answer:
Variations are beneficial for the survival of the species. Populations of organisms fill well-defined places in the ecosystem, using their ability to reproduce. However, these places can change because of reasons beyond the control of the organisms and could even wipe out the entire population. However, if some variations were to be present in a few individuals in these populations, there would be some chance for them to survive.
For example - If there were a population of bacteria living in temperate waters and suppose the water temperature was to be increased by global warming. Most of these bacteria would die, but the few heat resistant variants would survive and grow further. Variation is thus useful for the survival of species over time.
NCERT solutions class 10 science chapter 8 how do organisms reproduce topic 8.2 Modes of reproduction used by single organisms:
Q. 1. How does binary fission differ from multiple fission?
Answer:
Difference between binary fission and multiple fission-
| BINARY FISSION | MULTIPLE FISSION |
|
1. An organism divides into two similar organism 2. Does not form any layer.
3. It generally occurs in optimal condition.
|
1. An organism produces two or more organism 2. A cyst or thick layer is formed around the cell.
3. It can take place in any conditions.
|
Q. 2. How will an organism be benefited if it reproduces through spores?
Answer:
An organism is benefited if it reproduces through spores because spores are surrounded by a thick layer and due to this they can be protected in adverse conditions. In favourable condition, these spores continue to grow again.
In this way, they can manage to survive in unfavourable condition.
Answer:
Simple organisms like Hydra and Planaria can produce a new individual through the process of regeneration. However, In a complex multicellular organism have an organ-system level of organisation. Each organ systems of their body work together as an interconnected unit.
They have a high degree of organisation in their body. So, they cant be reproduced from their cut body parts by the regeneration process.
Q. 4. Why is vegetative propagation practised for growing some types of plants?
Answer:
Vegetative propagation- This method is used for growing certain types of plant which usually does not give any seed or produce non-viable seeds.
It is also used for plants growing which bears the superior traits because they produce genetically identical plants.
Q. 5. Why is DNA copying an essential part of the process of reproduction?
Answer:
DNA copying is an essential part of the process of reproduction so that the characteristics of the parent species are transmitted to it's down the line (offspring) and at the same time some variation also produced in the offspring.
This changes in the DNA provides an organism with the capability to survive in the changing condition.
NCERT solutions class 10 science chapter 8 how do organisms reproduce topic 8.3 Sexual reproduction:
Q. 1. How is the process of pollination different from fertilisation?
Answer:
Difference between pollination and the fertilization-
Pollination is the transfer of pollen grains from another stamen to the stigma of a capel. It takes place by certain pollinating agents such as air, water, birds and some insects etc.
On the other hand, fertilisation occurs when the male and female gametes fuse. It occurs inside the ovule and leads to the zygote formation.
Q. 2. What is the role of the seminal vesicles and the prostate gland?
Answer:
The role of the seminal vesicles and the prostate gland-
(i) Both secrets fluids which forms a part of the semen. The fluid of seminal vesical form 60% of the semen and the rest are from the prostate glands. It makes the path smooth through which sperm travels.
(ii) This fluid protects the sperm from the acid present in the urethra
(iii). Also, they can provide nutrition to the sperm in the form of calcium, fructose and some enzymes.
Q. 3. What are the changes seen in girls at the time of puberty?
Answer:
At the age of puberty, The following changes occur in girls-
- Mammary glands develop and enlarge.
- Hair grows under armpits and pubic region.
- Fallopian tube, uterus and vagina enlarge
- Menstruation starts
- Ovaries start to release eggs.
Q. 4. How does the embryo get nourishment inside the mother’s body?
Answer:
Inside the mother's body embryo gets nourishment from the mother's blood. There is a structure called placenta, it contains villi.
This provides a large surface area for glucose and oxygen to pass from the mother to the embryo.
Q. 5. If a woman is using a copper-T, will it help in protecting her from sexually transmitted diseases?
Answer:
No, Copper-T is a contraceptive method which prevents the formation of zygote inside the uterus.
It cannot prevent a woman from Sexually Transmitted Diseases.
CBSE NCERT solutions class 10 science chapter 8 how do organisms reproduce Exercise:
Q. 1. Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.
Answer:
The correct option is (b). In asexual reproduction, an offspring is reproduced from a single parent species. Yeast can reproduce by budding methods.
Q. 2. Which of the following is not a part of the female reproductive system in human beings?
(a) Ovary
(b) Uterus
(c) Vas deferens
(d) Fallopian tube
Answer:
The correct option is (c). Except for vas deferens, all the options are part of the female reproductive system. Vas deferens is a duct which conveys sperm from the testicle to the urethra.
Q. 3. The anther contains
(a) sepals.
(b) ovules.
(c) pistil.
(d) pollen grains.
Answer:
The correct option is (d). The anther is a part of stamen which contains pollen grains.
Q. 4. What are the advantages of sexual reproduction over asexual reproduction?
Answer:
Advantages of sexual reproduction:
- In sexual reproduction, more variations are produced. Thus, it ensures the survival of species in a population.
- The newly formed individual has characteristics of both the parents.
- Variations are more viable in sexual mode than in asexual one. This is because, in asexual reproduction, DNA has to function inside the inherited cellular apparatus.
Q. 5. What are the functions performed by the testis in human beings?
Answer:
The function of testis-
- It produces male gametes called sperms.
- It produces a hormone called testosterone which controls the development of reproductive organs and secondary sexual characters.
Q. 6. Why does menstruation occur?
Answer:
If the egg of the female does not get fertilised with the sperm, then the thick and soft lining of the uterus is no longer needed, and thus it breaks. Therefore, the lining of the uterus along with the blood vessels and the dead ovum (egg) comes out from the vagina in the form of blood called menstruation.
Q. 7. Draw a labelled diagram of the longitudinal section of a flower.
Answer:
Labelled diagram of the longitudinal section of a flower -
Q. 8. What are the different methods of contraception?
Answer:
The different method of contraception are as follows-
- Barrier method- In this method, condom, diaphragm and cervical caps are used. They prevent the entry of the sperm inside the female body during intercourse.
- Chemical method- In this method, women uses pills to suppress the release of an ovum in the fallopian tube.
- Contraceptive devices- Intrauterine contraceptive devices such as copper-T are placed in the uterus, and it prevents the sperms from reaching the uterus.
- Surgical method- In this method, vas deferens of the male and fallopian tube of the female is cut or tied by surgery.
Q. 9. How are the modes for reproduction different in unicellular and multicellular organisms?
Answer:
Difference between mode of reproduction in a unicellular and multicellular organism-
| IN UNICELLULAR | IN MULTICELLULAR |
|
1. Asexual reproduction takes place in the unicellular organism. 2. Only one Parent is required to produce offspring. 3. No special cells and organs are present for reproduction. |
1. Sexual reproduction takes place in the multicellular organism. 2. A male and female both are required in this method. 3. Special cell and organs are presents for reproduction |
Q. 10. How does reproduction help in providing stability to populations of species?
Answer:
The variation due to the reproduction gives stability to the population of various species by preventing them from getting erased during adverse condition. Reproduction also helps to produce copies of individuals which are adapted for a particular environment.
Q. 11. What could be the reasons for adopting contraceptive methods?
Answer:
The reasons for adopting contraceptive methods are-
- To control the birth rate. So that we can prevent an increase in population.
- To prevent from STDs
- To prevent unwanted pregnancy.
NCERT Solutions for Class 10 Science - Chapter wise
CBSE NCERT Solutions for Class 10 - Subject Wise
Benefits of CBSE NCERT solutions for class 10 science chapter 8 how do organisms reproduce:
- NCERT solutions for class 10 science chapter 8 how do organisms reproduce will give important tips and facts to remember for example, what can be the important diagrams to remember while preparing for board exams?
- For every question, there is a concept behind it. This concept has been explained in the solutions of NCERT for class 10 science chapter 8 how do organisms reproduce.
- Examples will be based on real life scenarios, therefore, you will be able to relate them to your surroundings. So, if you have any doubt, do not hesitate in asking our team of experts who will answer every query in an easy manner and as soon as possible.
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