7. How do Organisms Reproduce Science class 10 in English Medium ncert book solutions Long Additional Questions With Solutions

Additional Questions With Solutions

Q1. A couple wants to space the birth of their second child. Suggest one preventive method which could be observed 
(a) By the husband (b) By the wife for the same.
Ans: (a) Use of condoms by the husband
(b) Use of oral pills or loop or Copper-T by the wife.
Q2. A girl attains her puberty at the age of 11 years and a boy at 13 years but, still they are asked to refrain from sex, why? 
Ans: They are asked to refrain from sex because:-
(i) They are not physically, emotionally mature enough to be able to bear the responsibility of the child.

(ii) They may suffer from reproductive tract infections.
Q3. A pregnant woman visits a doctor to determine the sex of her child. The doctor refused to perform the test. Why is she being denied? 
Ans: The doctor refused to perform the test in order to prevent female foeticide which leads to an alarming decline in child sex ratio.
Q4. Blue prints of body design are stored in the DNA. Why? 
Ans: The chromosomes present in the nucleus of a cell contain information for inheritance of features from parents to next generation in the form of DNA molecule. The DNA is the information source for making proteins. Thus, blueprints of the body design are stored in the DNA.
Q5. Producing individuals by parents consume a lot of energy. So, why should an individual organism waste energy in the process, it does not need to stay alive?
Ans: Reproduction, unlike other life processes is not essential to maintain the life of an individual organism. But it is essential for providing stability to the population of species.
Maintaining the species is essential for maintaining balance in nature.
Q6. Protozoan reproduce by binary fission as well as by multiple fission. In your opinion which process is better and why? 
Ans: Multiple fission is better than binary fission because:-
1. More number of individuals is produced.
2. It helps to tide over unfavourable conditions.

Long Additional Questions with Answers – Chapter 7: How Do Organisms Reproduce?

Q1: What is reproduction? Explain its importance in living organisms.

Ans: Reproduction is the biological process by which living organisms produce offspring of their own kind. It ensures the continuity of a species and maintains the population of organisms.

Importance of Reproduction:

• Ensures the continuity of species.
• Prevents the extinction of organisms.
• Transfers hereditary characters from parents to offspring.
• Produces variations that help in adaptation and evolution.
• Maintains ecological balance.

Q2: Differentiate between asexual and sexual reproduction with suitable examples.

Ans:

Q3: Explain different methods of asexual reproduction with suitable examples.

Ans: Asexual reproduction takes place without the formation or fusion of gametes.

• Binary Fission: One parent divides into two identical daughter cells. Example: Amoeba.
• Multiple Fission: One parent produces many daughter cells simultaneously. Example: Plasmodium.
• Budding: A small bud develops on the parent body and grows into a new individual. Example: Hydra and Yeast.
• Fragmentation: The parent body breaks into fragments, and each fragment develops into a new organism. Example: Spirogyra.
• Spore Formation: Spores produced inside sporangia germinate under favorable conditions. Example: Rhizopus.
• Vegetative Propagation: New plants develop from roots, stems, or leaves. Example: Potato, Bryophyllum, Sugarcane.

Q4: Explain vegetative propagation. Mention its advantages and disadvantages.

Ans: Vegetative propagation is a method of asexual reproduction in which new plants are produced from vegetative parts such as roots, stems, or leaves.

Advantages:

• Produces genetically identical plants.
• Plants grow and mature quickly.
• Useful for seedless plants.
• Helps preserve desirable characteristics.

Disadvantages:

• No genetic variation is produced.
• Diseases can spread easily to all offspring.
• Reduced adaptability to changing environmental conditions.

Q5: Explain the structure and functions of the male reproductive system in humans.

Ans:

The male reproductive system consists of testes, scrotum, sperm ducts, accessory glands, urethra, and penis.

• Testes: Produce sperms and the hormone testosterone.
• Scrotum: Maintains the optimum temperature for sperm production.
• Vas Deferens: Carries sperms to the urethra.
• Accessory Glands: Add nourishing fluid to sperms to form semen.
• Penis: Transfers semen into the female reproductive tract.

Q6: Explain the structure and functions of the female reproductive system in humans.

Ans:

The female reproductive system consists of ovaries, fallopian tubes, uterus, cervix, and vagina.

• Ovaries: Produce ova and female hormones.
• Fallopian Tubes: Transport the ovum and are the site of fertilization.
• Uterus: Site of implantation and development of the embryo.
• Cervix: Connects the uterus to the vagina.
• Vagina: Receives sperms and acts as the birth canal.

Q7: Describe the process of fertilization and embryo development in human beings.

Ans:

During fertilization, a sperm fuses with an ovum in the fallopian tube to form a zygote.

The zygote undergoes repeated cell divisions to form an embryo.

The embryo moves to the uterus and gets implanted in the uterine wall. The placenta develops to provide oxygen and nutrients to the growing fetus and remove waste materials. After about nine months of development, the baby is born.

Q8: Explain the different methods of contraception. Why are contraceptive methods important?

Ans:

Contraceptive methods help prevent unwanted pregnancies and reduce the spread of sexually transmitted infections (STIs).

Methods of Contraception:

• Barrier Methods: Condoms and diaphragms prevent the meeting of sperm and ovum.
• Chemical Methods: Oral contraceptive pills prevent ovulation.
• Intrauterine Devices (IUDs): Copper-T prevents fertilization and implantation.
• Surgical Methods: Vasectomy in males and tubectomy in females provide permanent contraception.

Importance:

• Prevents unwanted pregnancy.
• Supports family planning.
• Helps control population growth.
• Reduces the spread of sexually transmitted diseases.

Q9: Explain sexual reproduction in flowering plants.

Ans:

Sexual reproduction in flowering plants involves pollination, fertilization, seed formation, and fruit development.

• Pollination: Transfer of pollen grains from the anther to the stigma.
• Fertilization: Fusion of male and female gametes inside the ovule.
• Zygote Formation: The fertilized egg develops into an embryo.
• Seed Formation: The ovule develops into a seed.
• Fruit Formation: The ovary develops into a fruit that protects the seeds.

Q10: Explain the importance of reproduction in the continuity and evolution of species.

Ans:

Reproduction is essential for maintaining life on Earth because it ensures the continuity of species. During reproduction, hereditary information is transferred from parents to offspring. Small genetic variations arise naturally, making some individuals better adapted to changing environmental conditions.

These beneficial variations improve survival and are passed on to future generations. Over time, the accumulation of such variations leads to evolution and the formation of new species. Thus, reproduction not only maintains the population but also contributes to biodiversity and the long-term survival of organisms.

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