Reproduction in Animals class 8 questions and answers: Science Class 8 chapter 6 question answer
| Textbook | Ncert |
| Class | Class 8 |
| Subject | Science |
| Chapter | Chapter 6 |
| Chapter Name | Reproduction in Animals ncert solutions |
| Category | Ncert Solutions |
| Medium | English |
Are you looking for Class 8 Science chapter 6 question answer? Now you can download ncert solutions for class 8 science chapter 6 pdf from here.
Question 1: Explain the importance of reproduction in organisms.
Answer 1: Reproduction is a vital phenomenon on this planet earth which is essential for existence and continuity of life and species on it, generation after generation.
Question 2: Describe the process of fertilisation in human beings.
Answer 2: Fertilization in humans occurs when a sperm cell from a male merges with an egg cell from a female, typically in the fallopian tube. The process begins when a mature egg is released from the ovary during ovulation and is captured by the fimbriae, which guide it into the fallopian tube. During sexual intercourse, sperm are ejaculated into the vagina and swim through the cervix and uterus to reach the fallopian tube.
Only one sperm typically penetrates the egg’s protective outer layer, triggering a series of chemical reactions that prevent other sperm from entering. Once the sperm enters the egg, their genetic material combines to form a fertilized egg, or zygote. The zygote then begins to divide and travel down the fallopian tube toward the uterus, where it will implant into the uterine lining and develop into an embryo.
Question 3: Choose the most appropriate answer.
(a) Internal fertilisation occurs
(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
(i) fertilisation (ii) metamorphosis (iii) embedding (iv) budding
(c) The number of nuclei present in a zygote is
(i) none (ii) one (iii) two (iv) four
Answer 3:
- (a) (i) in the female body
- (b) (ii) metamorphosis
- (c) (iii) two
Question 4: Indicate whether the following statements are True (T) or False (F).
(a) Oviparous animals give birth to young ones. ( )
(b) Each sperm is a single cell. ( )
(c) External fertilisation takes place in frog. ( )
(d) A new human individual develops from a cell called gamete. ( )
(e) Egg laid after fertilisation is made up of a single cell. ( )
(f) Amoeba reproduces by budding. ( )
(g) Fertilisation is necessary even in asexual reproduction. ( )
(h) Binary fission is a method of asexual reproduction. ( )
(i) A zygote is formed as a result of fertilisation. ( )
(j) An embryo is made up of a single cell. ( )
Answer 4:
- a) False
- b) True
- c) True
- d) False
- e) True
- f) False
- g) False
- h) True
- i) True
- j) False
Question 5: Give two differences between a zygote and a foetus.
Answer 5:
| Zygote | Foetus |
| (i) It is a single celled, i.e., it contains only one cell. | (i) It is multicelled, i.e., it contains many cells. |
| (ii) It is formed by the fusion of male gamete or sperm and female gamete or ova (egg). | (ii) It is formed by the repeated division of the zygote. |
Question 6: Define asexual reproduction. Describe two methods of asexual reproduction in animals.
Answer 6: Asexual reproduction is a type of reproduction in which offspring are produced from a single parent without the involvement of gametes (sperm and egg). The offspring are genetically identical to the parent, as no genetic material is exchanged.
Two methods of asexual reproduction in animals:
Budding: In this process, a new organism grows out of the body of the parent organism as a small bud. This bud eventually detaches and develops into a fully functional organism. Examples of animals that reproduce by budding include hydras and some species of corals.
Binary Fission: This is a method where a single organism divides into two identical daughter organisms. The parent cell splits into two equal parts, each of which becomes an independent organism. This method is commonly seen in unicellular organisms, such as bacteria and some protozoa.
Question 7: In which female reproductive organ does the embryo get embedded?
Answer 7: The embryo gets embedded in the uterus. Specifically, it attaches to the lining of the uterus, known as the endometrium, where it continues to develop into a fetus throughout pregnancy.
Question 8: What is metamorphosis? Give examples.
Answer 8: Metamorphosis is a biological process in which an organism undergoes a significant change in form and structure from its immature stage to its adult form. This process allows the organism to adapt to different environments or life stages. There are two main types of metamorphosis: complete and incomplete.
In complete metamorphosis, the organism goes through four stages: egg, larva, pupa, and adult (e.g., butterflies and frogs). In incomplete metamorphosis, the organism only undergoes three stages: egg, nymph, and adult, with nymphs resembling smaller versions of the adult (e.g., grasshoppers and cockroaches). This transformation helps organisms better survive in their changing environments.
Question 9: Differentiate between internal fertilisation and external fertilisation.
Answer 9:
| Feature | Internal Fertilization | External Fertilization |
|---|---|---|
| Definition | Fertilization occurs inside the female’s body. | Fertilization occurs outside the female’s body. |
| Location of Fertilization | Inside the reproductive tract (usually in the uterus or fallopian tubes). | In external environment (water, soil, etc.). |
| Examples | Mammals, birds, reptiles, some amphibians. | Fish, amphibians (e.g., frogs), most aquatic species. |
| Fertilization Process | Male deposits sperm inside the female, where egg is fertilized. | Eggs and sperm are released into the environment, where fertilization occurs. |
| Protection of Embryo | Embryo is protected inside the female’s body. | Embryo is exposed to environmental risks (predators, temperature changes). |
| Energy Investment | Usually higher energy cost for parents (e.g., care for young). | Lower energy cost for parents (little to no care after fertilization). |
| Number of Offspring | Usually fewer offspring, but with more parental care. | Often produces a large number of offspring with less parental care. |
| Fertilization Timing | Generally takes place during mating seasons, often coordinated. | Often occurs in synchronization with environmental conditions (e.g., water temperature, season). |
| Control Over Fertilization | More control over fertilization due to proximity of male and female. | Less control, as sperm and eggs are released into the environment. |
Question 10: 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 a 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 in vitro fertilisation.
4. These animals lay eggs.
5. A type of fission in Amoeba.
Answer 10:
- Across
- 1) Fertilization
- 6) Internal
- 7) Buds
- 8) Ovary
- Down
- 2) Testis
- 3) Zygote
- 4) Oviparous
- 5) Binary