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Kerala State Syllabus 8th Standard Basic Science Solutions Chapter 14 For the Continuity of Generations
For the Continuity of Generations Textbook Questions and Answers
For The Continuity Of Generations Biology Kerala Syllabus 8th Reproduction
In nature, there are various methods of reproduction to produce new generations.
For The Continuity Of Generations Kerala Syllabus 8th Budding
This is a method of asexual reproduction seen in Hydra, Yeast etc. The buds formed from the parent body detaches from it when mature and develop into a new organism.
Basic Science Class 8 Chapter 14 Kerala Syllabus Binary fission
Binary fission is seen in prokaryotes. Existing cell divides to form 2 new cells. In favorable conditions, bacteria-like organisms reproduce by binary fission
Kerala Syllabus 8th Standard Chemistry Notes Spore formation
This type of asexual reproduction is seen mainly in fungus. Spores are microscopic cells that can survive unfavourable conditions and develop into new organism on the return of favourable season.
Basic Science For Class 8 Chapter 14 Kerala Syllabus Pollination, Fertilization
Flowers are the sex organs in plants. Pollination is the process of transfer of pollen grains to the stigma of the flower. After pollination pollen tube grows towards the ovary. Simultaneously generative nucleus in the pollen grain divides at the pollen tube and two sperms are formed.
One of the sperms fuses with the ovum and forms the zygote. This process is called fertilization. The second sperm fuses with the polar nucleus in the ovary and forms the endosperm. Zygote develops into embryo and endosperm becomes the stored food for the growth of embryo.
Indicators (Text Book Page No:200)
Kerala Syllabus 8th Standard Chemistry Notes Malayalam Medium Questions 1.
Formation of male gametes
Answer:
After the pollination pollen tube grows towards the ovary. Simultaneously generative nucleus in the pollen grain divides at the pollen tube and two sperms are formed.
8th Class Biology Notes Pdf Malayalam Medium Questions 2.
Formation of embryo
Answer:
One of the sperms fuses with the ovum and forms the zygote. This process is called fertilization.
8th Class Biology Notes Pdf Kerala Syllabus Questions 3.
Formation of endosperm and its function
Answer:
The second sperm fuses with the polar nucleus in the ovary and forms the endosperm. Zygote develops into embryo and endosperm becomes the stored food for the growth of embryo.
8th Standard Chemistry Textbook Kerala Syllabus Male Reproductive system
The main parts of male reproductive system are Vas deferens, prostate gland, penis, testis etc.
Basic Science Class 8 Chapter 14 Solution Kerala Syllabus Vas deferens
Carries sperms from testis to urinary tract.
8th Standard Chemistry Textbook Kerala Syllabus Prostate gland
Secretes a fluid that contains factors required for the movement and nourishment of sperms.
Biology Class 8 Malayalam Medium Kerala Syllabus Penis
Deposits sperms into vagina
Basic Science Question Answer Chapter Wise Class 8 Testis
Produces sperms and male hormones.
Class 8 Science Notes Pdf State Syllabus Sperm
Sperm is motile. It has a head, middle piece and tail. Mitochondria present in the middle piece provides energy for movement. In the head, nucleus containing paternal chromosomes are present.
Indicators (Text Book Page No:201)
Questions 4.
Characteristics of sperms
Answer:
Sperms:- Sperms are motile. It has a head, middle piece and tail. Mitochondria present in the middle piece provide energy for movement. In the head, nucleus containing paternal chromosomes is present.
Questions 5.
Location of testes and the production of sperms
Answer:
Testis are found in the scrotal sac outside abdominal cavity. Sperms are produced in the testis.
Questions 6.
Importance of glands
Answer:
Sperms reach the penis along with the fluid produced by accessory glands and they are secreted to outside. Secretions provide a medium for the movement of sperms and nourishment
Female Reproductive System
Ovaries, Oviduct, Uterus, Endometrium, Vagina, etc., are the parts of female reproductive system.
Ovary – Produces Ovum and female hormones.
Oviduct – Fertilization takes place in oviduct.
Uterus – Foetus completes its development in uterus.
Endometrium – Inner layer of Uterus. Foetus attach the endometrial wall.
Vagina – Uterus opens out through Vagina. Sperms are deposited here.
Ovum
Ovum is larger than sperms. They are non-motile. There are specified membranes outside the cell membrane of ovum.
Indicators (Text Book Page No:202)
Questions 7.
Characteristics of ovum
Answer:
Ovum is larger than sperms. They are non-motile. There are specified membranes outside the cell membrane of ovum.
Questions 8.
Function of ovary
Answer:
Produces ovum and female hormones.
Questions 9.
Completing the table (Text Book Page No:202)
Answer:
| Characteristics | Sperm | ovum |
| Size | Microscopic cells | Larger than sperms |
| Movement (motility) | yes | No |
| Morpho logy | Parts like head, middle piece and tail are present | Specialized protective coverings Outside the Cell membrane |
Menstruation
With the onset of ovulation, there are certain preparations in the uterus to facilitate embryonic development. Endometrium becomes thickened, and more capillary are formed. But if fertilization does not take place the newly formed tissues disintegrate and peel off from the uterine wall. These get eliminated to outside along with blood and mu¬cus through vagina. This process is called menstruation.
Fertilization
Fertilization is the process of fusion of ovum, that releases from the ovary with the sperm in the oviduct.
Placenta
It is the part that connects embryo with the endometrium. Oxygen and nutrients are supplied to the foetus through the umbilical cord formed from the placenta. Waste materials from the foetus are also eliminated through placenta.
Questions 10.
Completing the table (Text Book Page NO:204)
Answer:
| Part | Function |
| Endometrium | Attachment of Embryo |
| Uterus | Complete development of foetus. |
| Placenta | Provides oxygen and nourishment to the foetus. Rem- oves wastes. |
| oves wastes. | Connects foetus with mother. Oxygen and nutrients are carried through umbilical cord. |
| Amnion | Amniotic fluids inside amnion present dehydration of focus and protects from external shocks |
Indicators (Text Book Page No:206)
Question 11.
What is adolescence?
Answer:
Adolescence is the period between puberty and adulthood.
Question 12.
How does adolescence influence the physical and mental development of an individual?
Answer:
The characteristics of adolescence like brain development, rapid increase in the height and weight, growth of reproduction organs, increased efficiency of glands, etc., influence the physical and natural development of individuals.
Question 13.
Why is the rate of adolescence growth higher in girls than in boys?
Answer:
In girls, the parts of brain that control physical and mental changes develop fast.
Question 14.
Is there any need to be anxious about the physical changes during adolescence? Why?
Answer:
No Adolescence is only a stage in growth. Bodily changes are part of development into a fully mature organism.
Adolescence and Food
Indicators (Text Book Page No:206)
Question 15.
What is the circumstance that led to the supply of iron-folic acid tablets to students?
Answer:
In adolescence severe anemia, due to deficiency of Iron was reported.
Question 16.
What is the role of food habits to overcome this situation?
Answer:
Including leafy vegetables, eggs, amaranthus, liver, etc., in the diet will help to check diseases like anemia.
Question 17.
How should the food habits be regularised so as to ensure the availability of nutrients for the rapid growth of body in adolescence?
Answer:
Vegetables, leafy vegetables, milk, egg, cereals, pulses, etc., should be included in the diet.
Need for assertiveness
Question 18.
What is your response towards this statement?
Answer:
Agree
Question 19.
Can you cite such instances?
Answer:
Invitation to practice alcohol, drugs, sex abuse, etc., temptation to do the dont’s, instances of crimes, etc.
Question 20.
How will you respond if such instances occur in your life?
Answer:
Say ‘No’.
Let us assess (Text Book Page No:211)
Question 21.
Which of the following activities takes place after fertilization in plants?
A. Pollen tube grows
B. Egg is formed in the ovary
C. Ovule becomes the seed
D. Male gametes are formed
Answer:
C. Ovule becomes the seed
Question 22.
Which part helps in the transportation of materials without mixing maternal and foetal blood?
A. Endometrium
B. Uterus
C. Placenta
D. Amni
Answer:
C. Placenta
Question 23.
Sequentially arrange the process that takes place after pollination in plants.
1. Embryo is formed
2. Pollen tube grows
3. Fertilization takes place
4. Male gametes are formed
5. Zygote is formed
6. Generative nucleus divides
Answer:
1. Pollen tube grows
2. Generative nucleus divides
3. Sperms are formed
4. Fertilization takes place
5. Zygote is formed
6. Foetus is developed
Question 24.
Substantiate the statement: “Excessive likes and dislikes of food materials adversely affects the health”.
Answer:
Avoiding food in order to become slim causes many diseases like anorexia. Overeating causes obesity and other chronic diseases.
Question 25.
Home hygiene and social hygiene are as important as personal hygiene for health. Do you agree with this opinion of the doctor who led an awareness class on health? Why?
Answer:
Definitely, unhygienic environment helps in the proliferation of pathogens. The dangers caused by pollution is much dreaded. Therefore home hygienic and social hygiene are very important as personal hygiene.
Question 26.
“Adolescence is full of challenges and possibilities”.
a. What are the challenges faced by adolescents?
b. What are your suggestions to overcome these challenges?
Answer:
- Causes mental and emotional disturbances.
- Confusion about his/her role in the society.
- Poor understanding about hygiene, immaturity.
- Possibility to addiction to bad habits.
- To survive these challenges
- Practice to say ‘No’ to wrong ways
- Parents should take care to make the environment in home pleasant
- Be careful while choosing friends.
- Take part in social services.
- Participate in co-curricular activities in the school.
Question 27.
It is easy to be addicted to drugs. But to escape from it is not that easy.
a. What should be our approach towards drugs?
b. What are the harmful effects of drugs?
Answer:
Never use drugs in your life. A single-use may push us to its addiction.
Harmful Effects
• Disease that leads to cancer are caused.
• Loss of social recognition
• Breaks interpersonal relationships. Loss of peace in the family and distortion of family relationship.
• Financial crisis arise
• Possibility to indulge in crimes
For the Continuity of Generations Additional Questions & Answers
Question 28.
Prepare a short note on the mode of reproduction in the organisms mentioned below. (Hydra, Bacteria, Fungi)
Answer:
Hydra: reproduces by budding. Buds are formed on the parent body. When it grows it gets detached from the parent and develops into new organisms.
Bacteria: reproduces by binary fission. An existing cell divides to two new cells.
Fungi: reproduces by spore formation.
Question 29.
Night-blooming flowers are while and having intense fragrance why?
Answer:
The smell and color of flowers is to attract insects.
Question 30.
“The disappearance of certain plants caused the extinction of some insects”- substantiate this statement.
Answer:
Certain insects depend only specific plants for their food and reproductive purposes; especially butterflies. Hence their destruction way leads to the extinction of the dependant species.
Question 31.
What is the function of tube nucleus and generative nucleus?
Answer:
Generative nucleus divides to form sperms. Tube nucleus disintegrates.
Question 32.
How does endosperm form?
Answer:
The second sperm fuses with the polar nucleus in the ovary and forms the endosperm.
Question 33.
What is the fate of Zygote, endo spermete?
Answer:
Zygote develops into embryo and endosperm forms the stored food for the development of embryo.
Question 34.
Find out the parts of the male reproductive system that performs the following functions?
1. Secrets the fluid containing nutrients for sperms
2. Secretes male hormones.
3. Carries sperms from the testis to ureter.
Answer:
1. Prostate gland
2. Testis
3. Vas deferens
Question 35.
Arrange the following state¬ments under the headings sperm Ovum.
1. Nonmotile
2. Parts like head, middle piece and tail are present.
3. Nucleus is present in the head,
4. Mitochondria is in middle piece.
Answer:
Question 36.
Are Ovulation and menstruation the same process?
Answer:
No. Ovulation is the process of release of mature ovum from the ovary. If fertilization does not take place the newly formed tissues in the uterine wall peel off and come, out along with blood and mucus through vagina. This process is called menstruation.
Question 37.
Find the odd one. Write the reason.
Endometrium, androgen, Oes-trogen, progesterone.
Answer:
Endometrium – Inner layer of uterus. Others are hormones.
Question 38.
How does placenta form? What is its function?
Answer:
Placenta is formed of fetal tissues and uterine tissues. Oxygen and nutrients are supplied to the fetus and waste materials are eliminated through the umbilical cord formed from placenta.
Question 39.
Fill in the blanks
1. Mushrooms are plants that reproduce by means of
2. During favorable conditions amoeba reproduces by
3. In tapeworm, both the male and female sex organs are found in the same organism. So it is said to be a
4. Each in man contains about eight hundred or more long coiled, minute tubules called seminiferous tubules.
5. The intimate mechanical and
physiological connection between fetal and maternal tissue is provided by
6. A cord containing blood vessels which connect the placenta with the fetus is called.
7.0n an average the length of menstrual cycle in females is completed in days.
8. A person infected with AIDS loses his
9. Male gamete fuse with ovule to form
10. The period of sexual maturity in human beings called
Answer:
1. spores
2. binary fission
3. hermaphrodite
4. testis
5. placenta
6. umbilical cord
7. 28
8. immunity
9. zygote
10. puberty
Question 40.
What is ‘after-birth’?
Answer:
About 15 minutes after the delivery of the baby, the placenta detaches from the uterine wall and is expelled out as ’after-birth’.
Question 41.
The lungs of the foetus are filled with fluid so it cannot breathe. But it doesn’t feel breathlessness. Why?
Answer:
A special tissue develops between uterine wall and the embryo called placenta. The growing foetus gets nutrients and oxygen from the mother’s blood through the placenta and umbilical cord. So it doesn’t feel breathlessness.
Question 42.
How is the structure of sperms adapted for fertilization?
Answer:
The vibrating tail of sperm helps to reach up to to ovum. The mitochondria present in the sperm provides energy for this movement. The enzyme produced by the acrosome present on the head of the sperm helps the sperm nucleus in penetrating the sheath of the ovum and entering the. ovum.