Andhra Pradesh SCERT Class 8 Biology Chapter 4 Solutions | APSCERT Semester 1
Andhra Pradesh SCERT Class 8 Biology 1st Semester Chapter 4 ‘Reproduction in Animals’ Solutions is available in this page.
Board |
Andhra Pradesh SCERT |
Class |
8 |
Subject |
Biology |
Semester |
1 |
Topic |
Solutions |
1.) Explain the importance of reproduction in organisms.
Ans. Reproduction is important for the continuation of a species. Every living organism is mortal within a period of time i.e. our human beings average life span is 60 years. Same-where different living organisms have different life span. In its living periods the organisms will associate with digestion, circulation, respiration, reproduction, excretion etc.
Reproduction means production of the new babies of the same kinds. It played a very important role for the existing of the same species in our earth. This will also helps to maintain the balance in nature. Every of living organisms depends on each other and creates a healthy food chain. If reproduction will not occur, the food chain will also vanish which will effect to survive the living things on earth.
2.) Describe the process of fertilization in human beings.
Ans. Fertilization is the first step of reproduction. When the male gamete fuses the matured egg of female gamete, in that time fertilization will take place. At this time, the nuclei of the male and female gamete fuse to form a single nucleus. This results in the formation of a fertilized egg known as zygote.
At the time of copulation the human male released several sperm cells, in where only one cell can penetrate inside the female gamete for fertilization. There are two types of fertilization will take place i.e. internal fertilization and external fertilization. Human beings are an example of internal fertilization.
3.) Choose the most appropriate answer.
(a) Internal fertilization occurs
(i) in female body.
(ii) outside female body.
(iii) in male body.
(iv) outside male body.
Ans. (i) in female body.
Explanation: Internal fertilization will take place inside the female body. When male gamete fuses the female gamete inside the female body then this type of fertilization will occur.
(b) A tadpole develops into an adult frog by the process of
(i) fertilization (ii) metamorphosis (iii) embedding (iv) budding
Ans. (ii) metamorphosis
Explanation: Metamorphosis is a process in where after the several steps the new baby will look like their parents. Like in frog,
Eggs —> Early Tadpole (having tadpole) —> Late Tadpole (having tails) —> Adult frog (like parent body)
(c) The number of nuclei present in a zygote is
(i) none (ii) one (iii) two (iv) four
Ans. (iii) two
Explanation: Zygote is a single cell organism having one nucleus. During fertilization, the nuclei of the sperm and the nuclei of egg (two nuclei) fuse to form that single nucleus.
4.) Indicate whether the following statements are True (T) or False (F).
(a) Oviparous animals give birth to young ones. ( )
Ans. False
Viviparous animals give birth to young ones.
(b) Each sperm is a single cell. ( )
Ans. True
Each sperm is a single cell having one nucleus. At the time of copulation human male will release nearly 200 to 300 million sperm cells, in where only one sperm cell success for fertilization.
(c) External fertilization takes place in frog. ( )
Ans. True.
In Frog external fertilization will take place. The female frog lay huge number of eggs at stagnant water / pond water. The male frog also releases sperm at the same water. When male and female gamete meets each other, then the fertilization will take place.
(d) A new human individual develops from a cell called gamete. ( )
Ans. False
A new human individual develops from a cell called zygote.
(e) Egg laid after fertilization is made up of a single cell. ( )
Ans. True.
When male gamete fuses the female gamete then the fertilization will take place known as zygote. Zygote is a single cell organism.
(f) Amoeba reproduces by budding. ( )
Ans. False
Amoeba reproduces through binary fusion. Hydra reproduces by budding.
(g) Fertilization is necessary even in asexual reproduction. ( )
Ans. False
When the male gamete fuses the female gamete, that period is known as fertilization. In asexual reproduction only one parent is needed. So, in this type of reproduction fertilization is not necessary.
(h) Binary fission is a method of asexual reproduction. ( )
Ans. True
Binary fission is a method of asexual reproduction. Amoeba reproduces in this process.
(i) A zygote is formed as a result of fertilization. ( )
Ans. True
A zygote is formed as a result of fertilization. We can’t identify the body parts of the babies in zygote.
(j) An embryo is made up of a single cell. ( )
Ans. False
Embryo is not made up of a single cell. After the zygote (single cell) is formed day by day cell is raised and formed embryo. In embryo period, we can identify baby’s body parts.
5.) Give two differences between a zygote and a foetus.
Zygote |
Foetus |
1.) Zygote is a single cell. |
1.) Foetus is a multi cell. |
2.) We cannot identified baby body parts in zygote. |
2.) We can identified baby body parts in foetus. |
6.) Define asexual reproduction. Describe two methods of asexual reproduction in animals.
The types of reproduction, in where only one parent is needed known as asexual reproduction.
The two methods of asexual reproduction are following:-
i) Binary fusion: Amoeba reproduces in this process. In this process, the process of reproduction begins by the division of its nucleus into two nuclei. This is followed by division of its body into two, each part receiving a nucleus. Finally two amoebas are produced from one parent amoeba.
ii) Budding: Hydra reproduces in this process. In parent hydra there may be one or more bulges. These bulges are the developing new individuals and they are called buds. Since new individuals develop from the buds in hydra, this type of asexual reproduction is called budding.
7.) In which female reproductive organ does the embryo get embedded?
Ans. Uterus.
8.) What is metamorphosis? Give examples.
Metamorphosis is a process in where after the several steps the new baby will look like their parents.
Example: Frog, Silkworm.
9.) Differentiate between internal fertilization and external fertilization.
Internal fertilization |
External fertilization |
1.) This type of fertilization takes place inside the mother womb. |
1.) This type of fertilization takes place outside the female body. |
2.) Fewer offspring are produced in this process. |
2.) More offspring are produced in this process. |
3.) Life span of the new baby is greater than external fertilization. |
3.) Life span of the new baby is shorter than internal fertilization. |
4.) This type of fertilization most occurred in land based animals. Ex, humans, animals, birds etc. |
4.) This type of fertilization most occurred in aquatic based animals. Ex, fish, starfish etc. |
10.) Complete the crossword puzzle using the hints given below.
Across
1.) The process of the fusion of the gametes.
Ans. Fertilization
6.) The type of fertilization in hen.
Ans. Internal
7.) The term used for bulges observed on the sides of the body of hydra.
Ans. Buds.
8.) Eggs are produced here.
Ans. Ovaries
Down
2.) Sperms are produced in these male reproductive organs.
Ans. Testes
3.) Another term for in vitro fertilization.
Ans. IVF
4.) These animals lay eggs.
Ans. Birds / Frogs / Lizard etc
5.) A type of fission in amoeba.
Ans. Binary fusion
Also See: AP Board Class 8 Science Chapter 3 Questions Answers