NCERT Solutions Class 8 Science Chapter 9
NCERT Solutions For Class 8 Science Chapter 9
Science, in general, is the pursuit of knowledge that includes broad facts or the operations of basic laws. It is a knowledge system concerned with the physical world and its phenomena involving unbiased observations and systematic experimentation. The area of study can segregate science into many disciplines.
In this article we will briefly discuss NCERT Class 8 Science Chapter 9 which is about Reproduction in Animals. This chapter covers asexual and sexual reproduction in animals, fertilisation and its various kinds, reproductive organs, and more.
Solving NCERT solutions is the first step to attaining excellent results in the examination. To help achieve the goal, Extramarks presents NCERT Solutions Class 8 Science Chapter 9. This Reproduction in Animals Class 8 Solutions has been developed so that students can easily comprehend all the concepts in the chapter. In addition to this, these solutions have been prepared exclusively by the Extramarks subject matter experts.
Not just NCERT Solutions for Class 8 Science Chapter 9, Extramarks has a repository of excellent quality study material. Material such as NCERT books, CBSE revision notes, CBSE sample papers, CBSE previous year question papers, and more can be easily found on the Extramarks website for all classes.
Key Topics Covered in NCERT Solutions For Class 8 Science Chapter 9
Mentioning below all the key topics that are covered in NCERT Solutions for Class 8 Science Chapter 9- Reproduction in Animals:
|Modes of Reproduction|
Let us look at Extramarks in-depth information on each topic in NCERT Solutions for Class 8 Science Chapter 9- Reproduction in Animals.
Modes of Reproduction
Extramarks’ NCERT Solutions for Class 8 Science Chapter 9 describes reproduction as a species’ survival depending upon its ability to reproduce. Therefore, reproduction is necessary because it assures the survival of similar individuals from generation to generation.
Types of Reproduction
There are two modes of reproduction:
- Sexual Reproduction
- Asexual Reproduction
Male and female reproductive organs are present in sexually reproducing plants. Males and females have diverse reproductive organs or parts in animals as well. In this sexual reproduction process, a male and a female partner’s gamete (the reproductive cells) fuse to form a new single cell which is known as a zygote. This zygote gradually develops from an offspring into an adult, similar to the mother and father. This type of reproduction beginning from the fusion of male and female gametes is called sexual reproduction.
Male Reproductive Organs
Males reproductive organs include two testicles, sperm ducts, and a penis.
Sperms: Male gametes known as sperm are produced by the testes.
Female Reproductive Organs
The female reproductive system consists of a uterus, two ovaries, and oviducts (fallopian tubes).
The ovary creates ova, which are female gametes (eggs).
Each month, one of the ovaries in humans releases one developed egg into the oviduct. The uterus is where the embryonic development of the child occurs. An egg is made up of only one cell, much like sperm.
In the process of sexcual reproduction the first step happens with the fusion of male and female gametes namely a sperm and an ovum. When sperms come in contact with an egg, one of the sperms fuses with the egg. The process of fusion of the sperm and the egg is called fertilisation
Extramarks NCERT Solutions for Class 8 Science Chapter 9 explains certain aspects of fertilisation as follows:
- Both gametes with a haploid (single) set of chromosomes fuse, resulting in a diploid or double number of chromosomes.
- A zygote is the name that is given to the fertilised ovum.
- Human fertilisation occurs in the fallopian tube, and the zygote is subsequently transported to the uterus.
- It divides several times inside the uterus, develops, and forms an embryo.
Internal fertilisation is the term used to describe fertilisation that occurs inside the female body. Internal fertilisation occurs in many animals. For example humans, dogs, hens, cows, etc.
External fertilisation is the term used to describe fertilisation that occurs outside the female’s body. External fertilisation can be seen in aquatic animals such as starfish, frogs, etc.
Development of Embryo
The nuclei of the sperm and the egg are fused to create a single nucleus during fertilisation. Zygote is the name for this fertilised egg.
The zygote repeatedly divides to form a mass (ball) of cells. The cells then start to separate into distinct tissues. We refer to this growing structure as an embryo.
For further development, the embryo embeds itself into the endometrium of the uterus and continues to develop and grow. In some time the body parts such as hands, feet, eyes, legs, etc. start developing. At this stage the embryo’s body parts are visible and it is now called a foetus. The foetus keeps growing and when completely developed the mother gives birth to a baby.
Viviparous and Oviparous animals
Viviparous animals are defined as organisms that give birth to offspring, including humans, cats, cows, and other mammals.
Oviparous animals, such as frogs, lizards, butterflies, etc., are those that lay eggs.
Young ones to adults
You probably witnessed a lovely moth erupting from its cocoon. Tadpoles change into adults that can swim and jump in water. Metamorphosis is the term for the process through which a larva develops into an adult, undergoing significant changes.
Extramarks NCERT Solutions for Class 8 Science Chapter 9 says that Asexual Reproduction occurs when only one parent is engaged in the reproductive process.
- There is no intermixing of genetic traits.
- Hydra buds, for example.
Extramarks NCERT Solutions for Class 8 Science Chapter 9 explains the various organisms and the Asexual reproduction methods they use to reproduce:
Budding is an asexual type of reproduction. Organisms, like a hydra, develop one or many bulges. These bulges are the developing new individuals and they are called buds. The new individuals develop as outgrowths of a single parent. This type of reproduction in which only a single parent is involved is called asexual reproduction. Since new individuals develop from the buds in hydra, this type of asexual reproduction is called budding. Another, example of asexual reproduction by budding is seen in yeast.
It is an asexual type of reproduction in which a single cell splits into two parts.
- The nucleus is divided first, second, the other cell organelles in the cytoplasm, and finally, the cytoplasm itself.
- As a result of this, one parent cell produces two offspring.
- Amoeba is an example of fission.
- Amoeba reproduces by dividing themselves into two cells; this process is known as binary fission.
Multiple fissions occur when one parent cell produces many daughter cells.
The above points mention a brief on the types of Asexual Reproduction as per Extramarks NCERT Solutions for Class 8 Science Chapter 9. To get a hold of more notes, refer to the Extramarks website.
NCERT Solutions For Class 8 Science Chapter 9 Exercise and Solutions
Extramarks primary focus is to bring quality study material to the students so that they can understand every concept and answer any question easily. This encourages the students to master the topic and increases their confidence in achieving a higher grade. These solutions are available for each and every chapter on the Extramarks official website. Click on the links given below to view NCERT Solutions for Class 8 Science Chapter 9:
Class 8 Science Chapter 9: Very Short Answer Type Questions
Class 8 Science Chapter 9: Short Answer Type Questions
Class 8 Science Chapter 9: Long Answer Type Questions
Students may access NCERT Solutions for Class 8 Science Chapter 9 and other chapters by clicking here. In addition, students can also explore NCERT Solutions for other classes given below.
- NCERT Solutions Class 1
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By getting access to NCERT Solutions for Class 8 Science Chapter 9, students can easily understand all the topics, and important keywords and solve questions given at the end of the chapter – Reproduction in Animals.
NCERT Solutions Class 8 Science Chapter-wise List
Key Features of NCERT Solutions For Class 8 Science Chapter 9
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Q.1 Explain the importance of reproduction in organisms.
Ans. Importance of reproduction in organisms is:
- Reproduction ensures the continuity of a species.
- It also maintains the number of individuals in a population.
- It is also responsible for variations in organisms in a population that help them to survive in the environment.
Q.2 Describe the process of fertilisation in human beings.
Ans. Fusion of a sperm and an ovum is called fertilisation. In human beings, the process of fertilisation takes place in the oviducts. The sperms produced by testes in male’s body are transferred into the female body. In female’s body, one matured ovum is released into the oviduct by one of the ovaries every month. In the oviduct, the sperm comes in contact with the ovum and fuses with it. During the process of fusion, the nuclei of the sperm and the ovum fuse to form one single nucleus. This results in the formation of zygote.
Q.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
(c) The number of nuclei present in a zygote is
(a) (i) in female body.
(b) (ii) metamorphosis
(c) (ii) one
Q.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. ( )
(a) Oviparous animals give birth to young ones. (F)
(b) Each sperm is a single cell. (T)
(c) External fertilisation takes place in frog. (T)
(d) A new human individual develops from a cell called gamete. (F)
(e) Egg laid after fertilisation is made up of a single cell. (T)
(f) Amoeba reproduces by budding. (F)
(g) Fertilisation is necessary even in asexual reproduction. (F)
(h) Binary fission is a method of asexual reproduction. (T)
(i) A zygote is formed as a result of fertilisation. (T)
(j) An embryo is made up of a single cell. (F)
Q.5 Give two differences between a zygote and a foetus.
Ans. Differences between a zygote and a foetus are:
|It is unicellular. Hence, no well-defined body parts.||It is multicellular and has well-defined body parts.|
|It forms due to the fertilisation of sperm and ovum.||It forms after the process of fertilisation in which zygote multiplies and grows into a multicellular body.|
Q.6 Define asexual reproduction. Describe two methods of asexual reproduction in animals.
Ans. Asexual reproduction is a type of reproduction in which only one parent is involved and the offspring is genetically identical to the parent cell.
Two methods of asexual reproduction are budding and binary fission.
- Budding: In this type of asexual reproduction, an outgrowth appears on the parent’s body. This outgrowth is termed as bud. The bud gradually grows into a small individual and then detaches itself from the parent’s body. It continues to grow and live as a new individual in the environment. Eg; Hydra.
- Binary fission: In this type of asexual reproduction, the nucleus of the parent’s body divides into two nuclei. After that the body divides into two and each body part receives a nucleus. Eg; Amoeba.
Q.7 In which female reproductive organ does the embryo get embedded?
Ans. The embryo gets embedded in the walls of uterus. In the uterus, the embryo grows and develops all the body parts.
Q.8 What is metamorphosis? Give examples.
Ans. Metamorphosis is a biological process of transformation of an immature form, such as larva, into an adult through drastic changes. It is observed in frogs (transformation of tadpole into adult frog) and in insects (transformation of larva into moths or butterflies).
Q.9 Differentiate between internal fertlisation and external fertlisation.
|Characters||Internal Fertilisation||External Fertilisation|
|Site of fertilisation||Inside female body||Outside female body|
|Number of eggs/offspring produced||Less||Large|
|Chances of survival of eggs/offspring||High||Low|
|Example||Mostly mammals||Generally fish and frog|
Q.10 Complete the crossword puzzle using the hints given below.
1. The process of the fusion of the gametes.
6. The type of fertilisation in hen.
7. The term used for bulges observed on the sides of the body of hydra.
8. Eggs are produced here.
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.
FAQs (Frequently Asked Questions)
1. What are the main topics covered in Extramarks NCERT Solutions for Class 8 Science Chapter 9?
The following topics have been covered in Extramarks NCERT Solutions for Class 8 Science Chapter 9:
- a) Modes of Reproduction
- b) Sexual Reproduction
- i) Male and Female Reproductive Organs
- ii) Fertilisation
- iii) Viviparous and Oviparous Animals
- iv) Young Ones to Adults
- c) Asexual Reproduction
- d) Narrative- Story of Dolly, the clone
By referring to the Extramarks website content, all the concepts of the chapter will be crystal clear to the students.
2. What is the importance of reproduction as per Class 8 Science Chapter 9?
The process through which a living creature generates more of its type is known as reproduction. Reproduction contributes to the continuation of their lineage. Therefore, it is critical to study and comprehend reproduction and understand the importance of it as no living thing can continue to exist without reproduction.