Class 8th Science ; Ch- Reproduction in Animals

 

Class 8th Science 

Ch- Reproduction in Animals 


Ques 1. Explain the importance of reproduction in organisms.

Ans.

  1. Reproduction ensures the continuation of similar kinds of individuals, generation after generation.
  2. Reproduction is essential for the continuation of a species.

Ques 2.Describe the process of fertilization in human beings.

Ans.

  1. In human beings fertilization takes place inside the female body (internal fertilization).
  2. Males eject sperms inside female bodies
  3. Out of millions of sperms produced, one sperm will fuse with the egg cell.
  4. This process in which the ovum and sperm fuse to form zygote is called
  5. During this process the nucleus of the sperm fuses with the nucleus of the ovum to form a single diploid cell i.e., zygote.

Ques 3. Choose the most appropriate answer :

a. Internal fertilisation occurs : ( i )

i) in female body ii) outside female body

iii) in male body iv) outside male body

b. A tadpole develops into an adult frog by the process of : ( ii )

i) fertilisation ii) metamorphosis iii) embedding iv) budding

c. The number of nuclei present in a zygote is : ( ii )

i) none ii) one iii) two iv) four

Ques 4. Indicate whether the following sentences are True (T) or False (F) :

  • a) Oviparous animals give birth to young ones. ( F )
  • b) Each sperm is a single cell. ( T )
  • c) External fertilization takes place in frog. ( T )
  • d) A new human individual developed from a cell is called gamete. ( F )
  • e) Egg laid after fertilization is made up of a single cell. ( T )
  • f) Amoeba reproduces by budding. ( F )
  • g) Fertilization is necessary even in asexual reproduction. ( F )
  • h) Binary fission is a method of asexual reproduction. ( T )
  • i) A zygote is formed as a result of fertilization. ( T )
  • j) An embryo is made up of a single cell. ( F )

Ques 5. Complete the crossword puzzle using the hints given below.

Across :

1. The process of the fusion of the gametes.

6.The type of fertilisation in hen.

7.The term used for bulges observed on the sides of the body of Hydra.

8.Eggs are produced here.

Down :

2.Sperms are produced in these male reproductive organs.

3.Another term for the fertilised egg.

4.These animals lay eggs.

5.A type of fission in Amoeba.

Class 8 Science Chapter 9

A.

Class 8 Science Chapter 9

Ques 6. Give two differences between a zygote and a foetus.

Ans. 

ZYGOTEFOETUS
i) The fertilised egg is called zygote.i) The stage of embryo in which all the body parts are identifiable is called a foetus.
ii) Zygote is single celled.ii) Foetus is multicellular.
iii) It is formed by the process of fertilisation.iii) It is formed after the multiplication of zygote.
iv) It has no well-defined body parts.iv) It has well defined body parts like limbs and other body part S


Ques 7. Define asexual reproduction. Describe the two methods of asexual reproduction in animals.

Ans. The method of reproduction in which only a single parent is involved is called asexual reproduction. (Or) The reproduction that occurs without formation and fusion of gametes is called asexual reproduction.

The methods through which animals reproduce asexually are Budding, Binary fission etc.

a) Budding :

  1. In this method, a part of an organism starts bulging out. This is called
  2. This bud gradually grows and develops into a separate individual.

Eg : Hydra, Yeast etc.

b) Binary fission : In this method, the nucleus of an organism divides into two followed by division of their bodies, each part getting one nucleus and developing into a separate individual.

Eg: Amoeba, Bacteria etc.

Ques 8. In which female reproductive organ does the embryo get embedded ?

Ans. Uterus is the female reproductive organ in which embryo gets embedded.

9. What is metamorphosis ? Give examples.

Ans. The transformation of the larva into adult through drastic changes is called metamorphosis.

Eg : Silkworm, Frog etc.


ZYGOTE		FOETUS
i) The fertilised egg is called zygote.i) The stage of embryo in which all the body parts are identifiable is called a foetus.
ii) Zygote is single celled.ii) Foetus is multicellular.
iii) It is formed by the process of fertilisation.iii) It is formed after the multiplication of zygote.
iv) It has no well-defined body parts.iv) It has well defined body parts like limbs and other body part S

Comments

Post a Comment

Popular posts from this blog

Diary Entry on Meeting an old friend

  Diary Entry on Meeting an old friend  Thursday ; 9th January ,2025 Dear Diary Today was a day filled with nostalgia and unexpected joy as I had the pleasure of meeting an old friend, someone I hadn't seen or spoken to in what felt like a lifetime. It was like rekindling a long-lost flame, breathing life into a forgotten chapter of my past. As I made my way to the little café where we had agreed to meet, my heart danced with anticipation. The memories of times we spent together flooded my mind, bringing back a sense of familiarity and warmth. I wondered whether those years would reflect on our faces or if the changes life had sculpted into us would be too profound to recognize. With each step, my pace quickened, and my heart pounded with excitement. Finally, as I reached the café, there they stood, smiling and radiating a familiar aura of comfort. Time stood still for a moment as I allowed our gaze to lock, embracing the joy of reconnection. Seated across from each other, ...
Read more

Class 6th .Application to attend Relative's Wedding

  To, The Principal (School name) Subject: Application for leave of Absence Sir/Ma'am, I am xxxxx(your name), student of class xxxx(class and division). With due respect, I would like to inform you that I cannot attend school from xx-xx-xxxx to xx-xx-xxxx (Date) due to my sister's wedding. Since I am the only brother of my sister I have lots of responsibilities and I have to make preparations for the same. I, therefore, request you to kindly grant me a leave of absence for those two days. Yours obediently Xxxxxxx (Your name) Class: Roll no:
Read more

Class 8th Science Ch- जंतुओं में जनन(Jantuo me janan) (Reproduction in Animals) Hindi Medium

Skip to conte जंतुओं में जनन (Reproduction in Animals) जनन जीव धारियों का एक बहुत ही महत्वपूर्ण है इस प्रक्रिया में जीवो की एक पीढ़ी दूसरी पीढ़ी को जन्म देते हैं जीवन की उत्पत्ति से लेकर आज तक जीवन की निरंतरता जीव  के जन्म के ही कारण बनी हुई है किसी स्पीशीज की जनसंख्या बढ़ाने का भी जनन एक साधन है जनन विकास में भी एक महत्वपूर्ण भूमिका निभाता है इस दौरान जीव अपने अनुकूल विविधताओं को एक पीढ़ी से दूसरी पीढ़ी में स्थानांतरित करता है (1) अलैंगिक जनन  (2) लैंगिक जनन 1. अलैंगिक जनन जब कोई जीव जनन के लिए अपने शरीर के किसी भाग कोशिका या कोशिकाओं अथवा किसी विशेष निर्मित रचना का इस्तेमाल करता है तथा इन संरचनाओं में कोई लैंगिक संलयन नहीं होता है तो या अलैंगिक जनन कहलाता है अलैंगिक जनन के फल स्वरुप उत्पन्न संताने पूर्णता अपने जनक जैसी होती हैं तथा इन संतानों में विभिन्नता एं होने की प्रायः सभावना नहीं होती है 2. लैंगिक जनन जब किसी जीव या एक ही जीव जाति के दो सदस्यों द्वारा उत्पन्न दो युगमको की संलयन से बने युग्मनज से संतान का जन्म होता है तो या जनन अलैंगिक जनन कहलाता है इस संतान में दोनों य...
Read more