Reproduction in Humans ICSE Class-8th Concise Selina Biology Solutions

Reproduction in Humans ICSE Class-8th Concise Selina Biology Solutions Chapter-3 .We Provide Step by Step Answer of Objective, True False , Fill in the blanks ,Match the following , Short/Long Answer Type of Exercise-3 Reproduction in Humans. Visit official Website  CISCE  for detail information about ICSE Board Class-8.


Reproduction in Humans ICSE Class-8th Concise Selina Biology Solutions Chapter-3


REVIEW QUESTION

Multiple Choice Questions:

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1. Put a tick mark (✓) against the correct alternative in the following statements:

(a) The testes are located within the:

  1. Penis
  2. Scrotum
  3. Ureter
  4. Urinary bladder

Answer

Scrotum

(b) Amoeba is most commonly reproduced by:

  1. Budding
  2. Regeneration
  3. Binary fission
  4. Multiple fission

Answer

Binary fission

(c) Identify the stage which is formed after the fertilisation of the egg by the sperm?

  1. Ovule
  2. Foetus
  3. Embryo
  4. Zygote

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Answer

Zygote

(d) Internally, the uterus opens into:

  1. Urethra
  2. Vagina
  3. Oviduct
  4. Vulva

Answer

Vagina

(e) Which one of the following represents the correct sequence in the life history of a butterfly ?

  1. Egg → Larva → Adult → Pupa
  2. Egg → Pupa → Adult → Larva
  3. Egg → Larva → Pupa → Adult
  4. Egg → Pupa → Larva → Adult

Answer

Egg → Larva → Pupa → Adult


Short Answer Questions Chapter-3 Reproduction in Humans ICSE Class-8th

Question 1.

Distinguish between the following pair of terms:
(a) Egg and sperm.
(b) Sexual reproduction and asexual reproduction.
(c) Budding and Regeneration.
Answer:

(a) Egg and sperm

Egg Sperm

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  1. Egg is produced in the ovaries.
  2. Egg is spherical in shape with a nucleus.

Sperm

  1. Sperm is produced in the testes.
  2. Sperm has head with nucleus, middle piece and tail.

(b) Sexual reproduction and asexual reproduction.

Sexual reproduction

  1. In sexual reproduction the two sexes i.e., male and female produce special type of reproductive cells sperms in the male and eggs in the female.
  2. To produce a new individual the sperm has to reach the ovum and fuse with it. e.g. Humans, bird, reptile, etc.

Asexual reproduction:

  1. It involves the production of an offspring from a single parent without the fusion of reproductive cells (gametes).
  2. It is a rapid mode of multiplication, e.g. Lower plants and animals {Amoeba).

(c) Budding and Regeneration 

Budding: Budding is a process in which buds grow on the outside of the parent body. The buds detach themselves when they are large enough.
Example: Hydra
Regeneration: Regeneration is the process that uses cell division to regrow lost body parts.
Example: Starfish, sponges

Question 2.

Define the following terms:
(a) Fetilization
(b) Implantation
(c) Puberty
Answer:

(a) Fetilization: When sperms and eggs from the opposite partners (males and females) fuse to form Zygote. It is called fertilization.

(b) Implantation: The fertilised egg (zygote) soon starts developing and by the time it reaches the uterus, a small ball of numerous cells is already formed. This is a kind of embryo which forms a pit in the wall of the uterus and gets fixed in it. This natural way of fixing of the embryo in the wall of the uterus is called implantation. This produces the state of pregnancy.

(c) Puberty: Puberty is the period during which the reproductive systems of boys and girls mature. In girls, it starts at the age of about ten and the first sign of puberty is the development of breasts. In boys, it starts at about 11 years of age of the^enlargement of the testes is its first sign. Sudden spurt in growth, shoulder girdle grows more than hip girdle.

Question 3.

State the reason why testes lie outside the abdomen in a scrotum?
Answer:
Both the testes remain in the scrotum because normal body temperature are to high, scrotum has smooth muscle tissues that keeps the testes at a cooler temperature than the body temperature 2°C to 3°C lower than the body temperature which is the most suitable temperature for sperm production.

Question 4.

Why is it important that a very large number of sperms should be present in the semen ?
Answer:
Single ejaculation of semen has 20,000,000 to 40,000,000 sperms. But only 1 or 2 sperms go into oviduct and fertilise the egg to form the Zygote. It forms embryo that forms an individual. It is the sperm in the semen that are of importance, and therefore semen quality involves both sperm quantity and quality.

Question 5.

List the structures, in their correct sequence, through which the sperms must pass from the time they are produced in the testes to the time they leave the urethra.
Answer:
They are produced in testes. They pass as follows:
The testes consist of a mass of sperm producing tube. The tubes join to form ducts leading to the epididymis which in.turn leads into a muscular sperm duct. The two sperm ducts, one from each testes, open at the top of the urethra.

Question 6. Reproduction in Humans ICSE Class-8th

State the functions of the following:
(a) Ovary
(b) Testes
(c) Fallopian tubes
(d) Seminal vesicle
(e) Uterus

Answer:


(a) Ovary: Ovaries produce ova (eggs) and secrete female sex hormones, oestrogen and progestrone.
(b) Testes: A pair of testes are present in human male. The testes produce sperms.

(c) Fallopian tubes: There are two fallopian tubes in the human female reproductive system. Fertilization occurs in the fallopian tube. It also conveys fertilized egg to the uterus.
(d) Seminal vesicle: The function of seminal vesicle is to store sperms and to secrete seminal fluid.

(e) Uterus: The inner lining recieves, protects and nourishes embryo. Contractions of muscular wall expel baby during birth.

Question 7.

Given here is a section of the female reproductive system of human beings.

female reproductive system of human beings

a) Name the parts labelled 1 to 4
(b) Name the part where fertilisation occurs in human beings.

Answer:


(a)

  1. Ovary
  2. Fallopian tube (Oviduct)
  3. Uterus (Inner lining or Muscular wall)
  4. Vagina

(b) Fertilisation occurs in the upper part of the oviduct.Sperm fuses withthe egg and zygote is formed this is called fertilisation.

Question 8.

Given alongside is a diagram of male reproductive system in humans. Label the parts indicated by numbers 1 to 5, and state their functions.

male reproductive system in humans.

Answer:

  1. Seminal vesicle: The seminal vesicles produce a secretion which serves as a medium for the transportation of the sperms.
  2. Prostate gland: Prostate gland which pours an alkaline secretion into the semen as it passes through the urethra.
  3. Testes: The Sperms are produced in the testes.
  4. Urethra: Urethra passes through the penis and carries either urine or semen.
  5.  duct sperm : The sperm pass through the sperm ducts.

Long Answer Questions: Reproduction in Humans ICSE Class-8th

Question PQ.

Define the term metamorphosis. Briefly describe the various stages occurring in the life-cycle of a butterfly.

Answer:


Metamorphosis:

A change in the form and often habits of an animal during normal development after embryonic stage complete transformation from an immature form to an adult form in two or more distinct stages.

Life cycle of butterfly:

The butterfly lays its eggs on the leaves of the plants. The new born that comes out of the egg is called larva. It passes through various stages of development. The larva of butterfly is also called Caterpillar. It is very active. and It is very voracious. and feeds and moves actively and gains size.

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