REPRODUCTION IN ORGANISMS - II : BRIEF ANSWERS

ANSWER IN BRIEF

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1. What is reproduction ? Mention its importance.
   

   ANS:
   The process by which organisms produce new organisms similar to them is known as reproduction.
   
   The importance of reproduction is :
   

   
   
   • It maintains the existence of each species.
     
   • It transfers hereditary characteristics to the next generation.
     
   • It brings concomitant changes in evolutionary events.
     

   
   

   
   
2. What is asexual reproduction ? Mention its types(methods).
   

   ANS:The process of reproduction in which any somatic part of the body of a single organism develops into a new organism is called asexual reproduction.
   
   Its types are :
   

   
   
   • fission
   • budding
   • spore formation
   • regeneration
   • vegetative propagation
     

   
   

   
   
3. What is vegetative propagation ? Mention its different methods.
   

   ANS:Development of a new plant from the root, stem or leaf is called vegetative propagation.
   
   The different methods of vegetative propagation are :
   

   
   
   • Cutting
   • Layering
   • Grafting
     

   
   

   
   
4. Write a note on fission as a method of reproduction.
   

   ANS:
   

   
   
   • Fission occurs in unicellular organisms.
   • It is a method of asexual reproduction.
   • Binary fission and multiple fission are its two types.
   • Amoeba, paramoecium,plasmodium,etc. reproduce by fission.
     

   
   

   
   
5. Explain : Binary fission.
   

   ANS:
   

   
   
   • It is a method of asexual reproduction occurring in unicellular organism.
   • An organism produces two unicellular organisms identical to the parent cell through mitotic division.
   • Amoeba, paramoecium,etc. reproduce by binary fission.
     

   
   

   
   
6. Write a note on puberty.
   

   ANS:
   

   
   
   • Puberty is the stage in the life of a human being when the reproductive organs show gradual change in structure and they become functional.
   • A boy attains puberty at the age of 13-14 years whereas a girl attains it at the age of 10-12 years.
   • During puberty,testes in male start producing sperms and sex hormone testosterone.
   • Similarly, ovaries in female start producing ovum and sex hormones estrogen and progesterone.
     

   
   

   
   
7. Mention accessory reproductive glands and their function in human male.
   

   ANS:Seminal vesicle,prostate gland and bulbourethral gland are the accessory reproductive glands in human male. The secretions of these glands form semen which provides movement to sperms so that they can reach the egg cell easily.
   

   
   
8. Mention the requirements of fertilisation of an ovum.
   

   ANS:
   

   
   
   • Ovulation must have occurred and hence the ovum must be present in the oviduct.
   • Copulation must occur before the ovum gets destroyed.
   • A sperm must reach the ovum to fertilise it.
     

   
   

   
   
9. Why is population control needed ?
   

   ANS:Population control is needed to control population growth which is the biggest problem in the world. Also, frequent deliveries can be dangerous for the health of a female and they can result in the birth of a weak(unhealthy) child.
   

   
   
10. Mention symptoms of STDs (Sexually Transmitted Diseases).
    

    ANS:
    

    
    
    • Inflammation of urinary tract and hence pain at the time of passing urine.
    • Lesions on skin of the urinary tract.
    • Itching sensation in penis or vagina.
    • Lesions on genital passage.
      

    
    

    
    
11. What individual care should one take to prevent STDs ?
    

    ANS:
    

    
    
    • One should keep awareness about the cleanliness of reproductive organs.
    • There must be limit in developing friendship with opposite sex.
    • One should use birth-control tools during intercourse to prevent such diseases.
    • One should learn to keep control on sexual desires.
    • Morality must be imposed as a religious practice.
      

    
    

    
    
12. Distinguish between menarche and menopause.
    
    ANS:
    
    
    
13. 
    

    ANS: