Reproduction in Animals: Question and Answers CBSE/NCERT For  Class 8th Chapter 9

Question: Explain the importance of reproduction in organisms.

Ans: Reproduction is a biological process by which living things develop progeny that resembles them. To sustain their population and ensure the survival of their species, living things reproduce.

Question: Describe the process of fertilization in human beings.

Ans: In male and female reproductive systems, the gametes of both sexes are discharged. The male reproductive organ, or penis, is where sperm or male gametes are released. The female body is then invaded by these sperms via the vagina. Once inside the fallopian tubes, they merge with the eggs there. Consequently, the fallopian tubes are where the process of conception occurs.

Question: Choose the most appropriate answer.

(a) Internal fertilization occurs

(i) In a female, internal fertilisation takes place.

(b) A tadpole develops into an adult frog by the process of

(ii) Through the process of metamorphosis, a tadpole grows into an adult frog.

(c) The number of nuclei present in a zygote is 

(ii) In a zygote, there is just one nucleus.

Question: Give two differences between a zygote and a foetus.

Zygote

1. It is an egg that has been fertilised through the union of the sperm and the egg.

2. To form an embryo, the zygote divides numerous times.

Foetus

1. It is an embryonic stage where all of the primary, recognisable body parts of an adult organism can be seen.

2. An embryo transforms into a foetus throughout time.

Question: Define asexual reproduction. Describe two methods of asexual reproduction in animals.

Ans: Asexual reproduction is a type of reproduction in which the male and female gametes do not fuse. It only needs one parent, and the children it produces are identical replicas of their parents.

Animals can reproduce asexually in two ways

A single cell divides into two halves during a process known as Binary fission, an asexual reproduction type. Bacteria and amoebas are examples of organisms that reproduce through binary fission. Cell division in amoebas can happen on any plane. It entails splitting its nucleus into two nuclei, which is followed by splitting its body into two parts, with a nucleus going into each half of the body.

Budding: Budding is the process by which a new individual develops from bulges, or buds, on the parent body. The Hydra frequently use this technique for reproduction. In Hydra, the cells quickly divide at one location, where they then expand into a protrusion known as the bud. These buds grow into smaller individuals while still being connected to the parent plant. These children separate from their parents’ bodies when they are old enough to become independent beings.

Question: The embryo embedded in which female reproductive organ?

Answer: The embryo becomes implanted in the uterine wall. While the embryo is still inside the uterus, it gradually grows into different bodily parts like hands, legs, head, and eyes. It is then referred to as a foetus.

Question: Define Metamorphosis? Provide examples.

Ans: A biological process called metamorphosis occurs when a larva develops into an adult. It entails quick and sudden changes in the animal’s body structure caused by cell development and differentiation. It is typically seen in insects, such as butterflies, and amphibians, such as frogs.

A frog goes through three stages in its life cycle: Tadpole, Egg, and Frog

Eggs are the product of external fertilisation, which develops into tadpoles that resemble fish.

Tadpoles can swim inside lakes and ponds because of their gills, small mouths, and fish-like tails.

A little frog, an amphibian by nature, develops from a tadpole as it grows and matures.

Question: Explain the differences between internal and external fertilisation.

Ans: Internal fertilization

1. The male and female gametes within the female body fuse during this process.

2. There are greater chances for the survival of the progeny. Consequently, only a few eggs are laid.

3. Fish, frogs, and starfish are examples of creatures that exhibit external fertilisation.

 External fertilization

1. The male and female gametes must fuse outside of the female body.

2. The likelihood of the kids surviving is lower. Consequently, a lot of eggs are produced.

3. Among creatures that exhibit internal fertilisation are people, cows, and chickens.

Question: Explain how human embryos develop.

Ans: Embryonic development is the process of creating and growing a human embryo. It is determined by the embryo’s early developmental processes of cell division and cellular differentiation. The human body develops from a single-celled zygote to an adult human being. A zygote is created during fertilisation, and this zygote later starts to develop into an embryo. A zygote is a collection of cells that regularly divides. Groups of cells are then formed, and they eventually give rise to the body’s numerous tissues and organs. The term “embryo” is used to describe this growing structure. The embryo is positioned in the uterine wall to continue developing there. The embryo develops further in the uterus. Over time, it grows physical features like hands, legs, a head, eyes, and ears. When a foetus is fully developed, it is at this stage of the embryo that all of the women give birth to the child.

(a)Zygote formation and embryonic development from the zygote;

(b) an expanded ball of cells; and

(c) implantation of the embryo in the uterus (enlarged)

Question: Define test-tube baby?

Ans: In-vitro fertilisation, or IVF, is a method used by women who have blocked oviducts and are unable to conceive naturally to create a test-tube baby. For IVF (in vitro fertilisation), doctors take freshly released eggs and sperm and keep them combined for a few hours (fertilisation outside the body). The zygote is given a week to develop if fertilisation occurs before being inserted into the mother’s uterus. Like any other infant, the baby grows completely inside the uterus before being born. Test-tube babies are those born in this manner. This is a misleading term because babies cannot develop in test tubes.

Question: Define metamorphosis.

Ans: The transformation of a larva into an adult with major alterations is called metamorphosis.

Question: Describe the two reproductive methods.

Ans: Asexual and sexual reproduction is also possible.

Question: Name three components of the male reproductive system.

Ans: The three components of the male reproductive organs are the testes, penis, and urethra.

Question: Any three components of the female reproductive system should be mentioned.

Ans: The female reproductive system consists of the ovary, oviduct, and uterus.

Question: List any two creatures that use external fertilisation as examples.

Ans: Fish and frogs are two examples of species that use external fertilisation.

Question: Name any two viviparous creatures as examples.

Answer: Two viviparous animals are humans and elephants.

Viviparous animals are those that reproduce and have young or young offspring.

Question: List the several forms of asexual reproduction.

Ans: Some examples of asexual reproduction are budding and fission.

Asexual reproduction enables a person to procreate independently of another species member.

Question: Define sperms?

Ans: The male gametes known as sperm are produced by the testes. Sperm have a head, a centre, and a tail despite their small size.

Question: Define ovum.

Ans: The ovary produces female gametes called ova (plural: ovum). It has a spherical shape and a nucleus in the centre surrounded by cytoplasm.

Question: Define ertilization.

Ans: The process of fusing male and female gametes to create a zygote is called ertilization.

Question: Distinguish between viviparous and oviparous animals.

Ans: The following are the distinctions between viviparous and oviparous animals.

Viviparous

1. Giving birth to a young child

2. Within the mother’s womb, young kids develop.

A lion, A dog, or A cat, for instance.

Oviparous

1. Lay Eggs, But Do Not Develop Embryos Inside Mother.

For instance, fish, frogs, reptiles, and insects.