Kerala SCERT Class 8 Science Chapter 14 For the Continuity of Generations Question Answer Solution Here. Kerala Board Class 8 Students can find Here 14th Chapter For the Continuity of Generations Notes provide by our Teacher. Important Question Answer from Chapter 14 For the Continuity of Generations.
- Board- Kerala Board.
- Class – 8.
- Subject – Basic Science Part 2
- Chapter – 14.
- Chapter Name – For the Continuity of Generations.
- Topic – Question Answer Solution.
Answer the following
1) Which organisms are involved in male reproductive system?
Ans- Vas deferens, prostate gland, penis, testis etc are involved in male reproductive system.
2) List the name of organism involved in female reproductive system.
Ans- Ovary, Fallopian tube, Uterus , Endometrium, Vagina etc are involved in female reproductive system.
3) What is menstruation?
Ans- Menstruation is a natural biological process that takes place in girls as part of their physical growth.
4) What are hormones?
Ans- hormones are chemical substances produced in the endocrine glands of the body .
5) Define the followings-
a) Sperm –sperm is the male gamete. It is motile and microscopic. The sperm has a head, middle piece and a tail.
b) Zygote-
c) Ovum- Ovum is the female gamete. It is larger than a sperm and not motile.
d) Placenta- placenta is the apart by which the embryo attaches itself to the endometrium and develops.
e) Pollengrain- pollen grain is the microscopic structure which contain two nuclei such as generative nucleus and tube nucleus.
f) Pollination-pollination is the process of transfer of pollen grains from the male anther to the female stigma.
g) Parturition- during the gastration period of human being the feotus completes its growth through gradual changes and the fully grown baby comes out thorugh the vagina this process is called parturition.
Answer the following questions-
1) Explain the male reproductive system with Diagram.
Ans- male reproductive system involved following organisms-
Vas deferens- The duct that carries sperms from the testes to the ureter.
Prostate gland -Produces secretion that contains the factors required for the nutrition and movement of gametes.
Penis- Formed of specialised muscles and blood spaces. Urine and semen come out through the duct (ureter) inside the penis .It helps to deposit sperms in the vagina.
Testis – Seen inside the scrotal sac. Produces sperms and male hormones.
Diagram-
2) Write short note on sperm.
Ans- : Sperm is the male gamete. It is motile and microscopic. The sperm has a head, middle piece and a tail. They move with the help of the tail. Mitochondria, present in the middle piece, provides the energy for movement. Nucleus that contains paternal chromosomes is seen in the head. Sperms are formed inside a pair of testes located in the scrotal sac outside the abdominal cavity. Testis also produces testosterone, the male sex hormone. Temperature less than the body temperature (35-36oC) is favourable for the formation of sperms. The scrotal sac helps to maintain this temperature. Sperms along with the secretion of glands including the prostate gland reaches the penis and is secreted outside. This process is called insemination.
Diagram-
3) Give detail about female reproductive system with a neat labelled diagram.
Ans- the female reproductive systems involved following organism-
Ovary- produces ovum and female hormones.
Fallopian tube/ oviduct- Carries ovum to the uterus. Fertilization takes place in the Fallopian tube.
Uterus- Foetus complete its growth in uterus.
Endometrium- Inner layer of the uterine wall. Foetus grows by adhering to the endometrial wall.
Vagina- Part through which uterus opens out. Sperms are deposited here.
4) Write about budding, binary fission and spore formation.
Ans- Budding- Buds are formed in the parent body. When it grows, it separates itself from the parent body and develops into a new organism.Example – Hydra
Binary fission – An existing cell divides to from two new cells. Under favourable conditions, rapid multiplication of organsims like bacteria take place by binary fission.Example- Bacteria
Spore formation- spores are minute cells that can survive in unfacourable conditions and develop into new organisms under favourable conditions. This is a type of asexual reproduction. Example-Fungus
Answer the following questions in brief.
1) Give short note on-
a) Hormones- Hormones are chemical substances produced in the ndocrine glands of the body. Hormones control and coordinate various life processes. Therefore any variation in the secretion of hormones affects the life process considerably.
b) Parturition- during the gastration period of human being the feotus completes its growth through gradual changes and the fully grown baby comes out thorugh the vagina this process is called parturition. The growth of foetus and the birth of the baby are complex processes . only a woman with physical and mental maturity can accept these changes and give birth to a healthy baby.
c) Ovum-Ovum is the female gamete. It is larger than a perm. Ovum is non- motile. Specialized protective layers are seen outside the cell membrane of the ovum.
A Pair of ovaries situated in the abdominal cavity producers ova, and the female sex hormones called estrogen and progesterone. Ovulation is the process of releasing mature ovum from the ovary. Normally one ovum matures per month.
d) Placenta-Placenta is the part by which the embryo attaches itself to the endometrium and develops. Placenta is composed of foteal tissues and uterine tissues. Oxygen and nutrients reach the foetus through the umbilical cord developed from placenta. Waste materials are also eliminated through the placenta. Placenta helps in the exchange of materials between the mother and the foetus without mixing their blood. The growth of the foetus completes within the amnion, the membraneous covering formed from the embryonic cells during the intial stages of growth. The amniotic fluid within this covering prevents dehydration of the foetus and protects it from shocks.
2) Write about Adolescence in brief.
Ans- Adolescence – a special phase in life
Adolescence is a period of biological significance. This is a period of rapid changes from childhood to adulthood. According to the statistics of World Health Organisation (WHO), the adolescence period is from 11 to 19 years. This is a period from the onset of puberty to the completion of physical growth. Puberty relates to the physical changes that occur in individuals, thereby making them capable of reproduction. In each individual, the adolescence begins with physical changes. Development of brain, rapid increase in height and weight and increased efficiency of glands are the significant features ofthis period.
Changes related to adolescence are more rapid in girls than in boys. Thisis because the parts of brain that control physical and mental changesdevelop rapidly in girls. Along with the rapid physical changes, intensemental and emotional changes make adolescence a significant period inone’s life.
3) Write the physical changes in adolescence occurs in boys and girls.
Ans- following are the physical changes observed in adolescences-
Fats growth | Fast growth |
Growth of sex organs gains momentum | Growth of sex organs gains momentum |
Hair grows in various parts of the body
(pubic region, armpits, face , chest) |
Hair grows in the pubic region and the ampits |
Pitch of the voice deepens | Pitch of the voice becomes sharp |
Glands in the skin become more active | Glands in the skin become more active, breast |
Shoulder bonds expand. | Hip bones widen. |
Ejaculation stars | Menstruation starts |
4) What food and other precaustions should take for good health.
Ans- In the adolescence proper nutrition is necessary for the growth. There are some tips for food which have to follow-
a) Breakfast is very important. Do not skip it during busy schedule.
b) Have right quantity of food at the right time.
c) Choose a diet that includes fruits , vegetables and pulses.
d) Reduce the intake of fried food items.
e) Use sugar and salt in limited quantities.
f) Do not be habituated to bottled drinks , packet food and fast food.
g) Develop the habit of using seasonal leafy vegetables and fruits avialbale in the locality.
5) What is anaemia? Write causes and remedies.
Ans- Anaemia is a condition caused either by reduction in the number of red blood cells in the blood or by the deficiency of haemoglobin , the pigment in the red blood corpuscles. When anaemic blood loses its capacity to carry oxygen and the person feels weak and exhausted. It also causes loss of memory and concentration as anaemia affects brains efficiency.Deficiency of iron in the body is one of the causes of anaemia. Through the iron tablets may e used as an immediate solution, it is advisable to ensure the avilability of nutrients through regularistaion of food habits.
MCQ
1) —– is the condition caused either by the reduction in the number of red blood cell.
a) Anaemia
b) Asthama
c) Hipitatis B
d) None of the above
Ans- a) Anaemia
2) what is the part by which the embryo attaches it self to the endometrium and develops.
a) zygote
b) ovum
c) placenta
d) uterus
ans- c) placenta
3) ovum is the—– and testis is the—– Gamets.
a) female and male
b) male and female
c) none of the above
ans- a) female and male
4) Hydra is the example of——
a) binary fission
b) budding
c) bacteria
d) fungus
ans- b) budding
5) the general menstrual cycle repeats one in —- days
a) 30
b) 32
c) 25
d) 28
Ans- d) 28
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