Reproduction In Animals

Reproduction is an important life process which ensures that a plant or animal species does not disappear from this earth.

(a) In sexual reproduction, two parents are involved.

(b) In asexual reproduction, only one parent is involved.

Cows and dogs are reproduce sexually.

Hydra and planaria reproduce by asexually.

Human beings reproduce by sexual method.

(a) Sexual reproduction involves gametes.

(b) Asexual reproduction does not involve gametes.

The another term for a fertilized egg is zygote.

The process by which male and female gametes fuse to each other is called fertilization.

No. All organisms do not give birth to individuals like humans. .

Sex cells are also known as gametes.

In humans, testes (in male) and ovaries (in female) are reproductive organ which produces the gametes.

The male gametes in human are called sperms.

Testes produce male gametes called sperms.

The female sex cells (gametes) in humans are called eggs.

Ovary produces female sex cells called eggs.

Testes produce male gametes (sperms) in humans.

Ovaries produce egg (or ova) in humans.

Testes in a man produce male gametes called sperms.

Ovaries in a woman produce female gametes called eggs.

Penis is an organ which passes the sperms from the man's body into the vagina in the women's body during mating.

The embryo gets embedded in the wall of the uterus for further development.

Embryo stage comes earlier in the development of a human baby from zygote.

In vitro fertilization (IVF) technique is used to help a woman with blocked oviducts to have a baby.

The full name of IVF is in vitro fertilization (fertilization outside the body).

The success rate of IVF technique is only about 30 to 40 percent.

Internal fertilization takes place in a hen.

The transformation of the larva (tadpole) into an adult (frog) through drastic changes is called metamorphosis.

Frog and silk moth produce embryos that grow into larvae before transforming into adults.

These bulges are the developing new individuals and they are called buds.

Binary fission takes place in Amoeba.

(a) Amoeba reproduces by common asexual method called binary fission.

(b) Budding is asexual method of reproduction in hydra.

(a) Hydra reproduce by asexual method called budding.

(b) Amoeba reproduce by binary fission, a asexual method.

Cloning is the technique which was used in producing ‘Dolly’ the sheep.

Dolly was a healthy clone of the Finn Dorsett sheep.

An animal which is an exact copy of its parents is called clone.

There are two methods of reproduction:

(i) Sexual reproduction (ii) Asexual Reproduction

(a) True, sperm is a single cell with all the usual cell components.

(b) False, A new human individual develops from a cell called zygote.

(c) True, egg laid after fertilization is made up of a single cell.

(d) True, Fertilization results in the formation of zygote which begins to develop into an Embryo.

(e) True, External fertilization takes place in frog and fish.

(f) False, embryo is a developing structure which is made up of group of cells.

(g) False, those animals which lay eggs are called oviparous animals.

(h) True, Internal fertilization takes place in hens, humans and cow.

(i) False, Hens are oviparous animals which lay eggs.

(j) False, Amoeba reproduce by binary fission.

(k) True, Binary fission is a method of asexual reproduction.

(l) False, fertilization is not necessary in asexual reproduction.

(m) False, Cloning is the production of an exact copy of a cell, any other living part, or a complete organism.

(a) reproduction

(b) gametes

(c) zygote

(d) fertilization

(e) ovum

(f) smaller

(g) month

(h) oviparous

(i) viviparous; oviparous

(j) metamorphosis

(k) tadpole

(l) binary fission; budding

(m) cloning

Difference between asexual and sexual reproduction:

Sexual method: Cats, humans, birds

Asexual method: Amoeba and Hydra

Internal fertilization: Fertilization which takes place inside the female body is called internal fertilization. Internal fertilization occurs in many animals including humans, cows, dogs and hens.

External fertilization: This type of fertilization in which the fusion of a male and a female gamete takes place outside the body of the female is called external fertilization. It is very common in aquatic animals such as fish, starfish, etc.

The diagram of the human female reproductive system is shown below:

a) In the human body, an egg (or ovum) gets fertilized in the fallopian tubes.

b) The fertilized egg (or zygote) develops into a baby in the uterus of the human body.

Internal fertilization – (a) Cows (c) Humans (e) Hen

External fertilization - (b) Frog (d) Fish

The female frogs (or female fish) lay hundreds of eggs because there are fewer chances of surviving in that environment, so from 100 even if 5-10 survive, their species will survive.

The zygote divides repeatedly to give rise to a ball of cells. The cells then begin to form groups that develop into different tissues and organs of the body. This developing structure is termed an embryo.

The stage of the embryo in which all the body parts can be identified is called a foetus.

(i) Zygote is made up of a single cell while foetus is made up of many cells.

(ii) Zygote is formed by the fertilization of sperm and ovum, foetus is formed by the repeated divisions of the zygote.

Following steps are involved in the process of sexual reproduction in an animal:

(i) In the animal, male parent produces male gametes called sperms. Millions of sperms are produced by testes.

(ii) The female parent produces female gamete called ova (eggs). Like a sperm, an egg is also a single cell.

(iii) The next step is fertilization. In this step, sperm enters the ovum and fuses with it to form a new cell called zygote. The zygote is the beginning of a new individual.

(iv) In this step, zygote begins to develop into an embryo. The zygote divides repeatedly to form a large number of cells and ultimately the zygote grows and develops to form a baby.

The stage of the embryo in which all the body parts can be identified is called a foetus. A human embryo becomes a foetus after about 8 weeks of pregnancy.

The transformation of the larva into an adult through drastic changes is called metamorphosis. Metamorphosis occurs in frog and silk moth.

Difference between viviparous animals and oviparous animals:

Oviparous animals – Frog, sparrow, lizard, hen, fish, butterfly

Viviparous animals – Human being, dog, cat.

(a) The animals which give birth to young one are called viviparous animals. In such animals, the baby develops inside the body of the mother.

Examples of Viviparous animals – Human beings, cat, dog, cow, tiger.

(b) The animals that reproduce by laying eggs are called oviparous animals. In such animals, the baby develops inside eggs that the mother lays.

Examples of Oviparous animals – Frog, sparrow, lizard, hen, fish, butterfly.

In hens, internal fertilization take place but they do not give birth to chicks like human beings. After fertilization, the zygote divides repeatedly to form embryo which travels down the oviduct. As it travels down, many protective layer are formed around it.

The outermost protective layer is hard shell which we can see in a hen’s egg. After the hard shell is formed around the developing embryo, the hen finally lays the egg. The hen, then sits on the egg to provide sufficient warmth to the eggs for the development of the embryo into the chicks. The embryo takes about 3 weeks to develop into a complete chick.

(a) Viviparous animals –Cow, deer, cat, tiger, dog.

(b) Oviparous animals – Ostrich, frog, lizard, snake, hen.

Frog and silk moth undergo metamorphosis whereas cow and hen do not undergo metamorphosis.

Butterfly, silk moth, frog, housefly and mosquito undergo metamorphosis while cow, human, hen and monkey do not undergo metamorphosis.

The cells involved in sexual reproduction are called gametes.

Fertilization is the step of reproduction in which fusion of gametes take place.

Zygote is formed when two gametes are fused together.

The fusion of a sperm with an ovum to form a zygote during sexual reproduction is called fertilization.

(i) (d); (ii) (a); (iii) (b); (iv) (c)

Differences between internal fertilization and external fertilization:

(a) In frog, external fertilization takes place.

(b) In fox, internal fertilization takes place.

Cloning is the production of an exact copy of a cell, any other living part, or a complete organism. Yes, gametes are involved in cloning. Dolly and noah are two cloned animals.

Reproduction is one of the important characteristics of living things. The ability of organism to produce young ones of its own kind is called reproduction. It is essential for the continuation of a species.

The type of reproduction in which only a single parent is involved is called asexual reproduction. Binary fission and budding are two methods of asexual reproduction in animals. Amoeba reproduce by binary fission and Hydra reproduce by budding.

The organisms which are produced asexually are genetically identical to the parent and are called clones.

Dolly was born on 5^th July 1996 and was the first mammal to be cloned.

The fusion of male and female gametes to form zygote is known as fertilization. The process of fertilization takes place in the fallopian tube (oviduct). As sperm enter into the vagina through the process of copulation; it moves upwards and enter into the oviduct. In the oviduct, ovum fuse with the sperm to form zygote.

In vitro fertilization technique is used to help those couples in having babies who can produce sperms and ovum but fertilization does not take place inside the woman’s body due to blocked oviducts.

In IVF or invitro fertilization technique, is a process by which an egg is fertilised by the sperm outside the body.

The process involves monitoring and stimulating a woman's ovulatory process, removing ovum or ova (egg or eggs) from the woman's ovaries and letting sperm fertilise them in a fluid medium in a laboratory.

The animals which give birth to young ones are called viviparous animals. Human beings and cow are examples of viviparous animals.

Those animals which lay eggs are called oviparous animals. Examples - Hens and frog.

Amoeba reproduces by common asexual method called binary fission. In this method, Amoeba cell divides into two equal daughter cells. The nucleus of amoeba first divides into two parts. After that the cytoplasm of amoeba divides into two parts, one part around each nucleus. This leads to the formation of the two daughter Amoebae cell having a nucleus and its own cell organelles.

Hydra reproduces by budding. In hydra, there may be one or more bulges. These bulges are the developing new individual and they are called buds. This bud then grows gradually to form a small hydra by developing a mouth and tentacles. The tiny new hydra detaches itself from the parent body and become new independent individual.

Fertilization which takes place inside the female body is called internal fertilization.

The correct answer is one nucleus is present in the zygote.

Explanation: Zygote is the formed due to fertilization of the gametes. During fertilization, the nuclei of the sperm and the egg fuse to form a single nucleus.

The correct answer is option (b) i.e. metamorphosis

Explanation: The transformation of the larva into an adult through drastic changes is called metamorphosis. Metamorphosis occurs in frog and silk moth.

The process by which male and female gametes fuse to each other is called fertilization.

Oviducts is not a part of male reproductive system. It is a part of female reproductive system.

Rat, rabbit and cat are viviparous animals whereas lizard is a oviparous animal because it lays egg.

Hydra is a multicellular organism which reproduce by budding.

In asexual reproduction, two offsprings having the same genetic material and the same body features are called clones.

Frog, silk moth and mosquito undergo metamorphosis whereas fish does not show metamorphosis.

Asexual reproduction is a method producing generally identical offsprings.

Amoeba, a unicellular organism reproduce by binary fission.

Snake, fish and frog are oviparous animals whereas rat is viviparous animals.

Tadpole is the larva of frog.

Cloning is the production of an animal by asexual reproduction.

Scrotal sac is a part of the human male reproductive system.

Reproduction is one of the important characteristics of living things. The ability of organism to produce young ones of its own kind is called reproduction. It is essential for the continuity of species.

Ovary is the structure that occurs in the reproductive system of flowering plants as well as of humans. In both of them, it produces female gametes called egg.

The testes are located outside the abdominal cavity in the scrotum because the temperature of scrotum is less than the normal body temperature which is requires for sperm formation.

Characters that are transmitted from parents to offspring during sexual reproduction show both similarities and variations with parents.

The offspring formed as a result of sexual reproduction exhibits more variations because genetic material comes from two parents of same species.

(a) X is Yeast.

Explanation: Yeasts are unicellular fungi which convert glucose into alcohol through the process of fermentation.

(b) The process in which X converts sugar into alcohol is called Fermentation.

Explanation:The following chemical reaction takes place:

Yeast + Glucose → Alcohol (l) + CO₂ (g)

(c) The organism X i.e. Yeast belongs to the fungi of living organisms.

Explanation: Yeast is a single-cellular organism which divides by mitosis and shows budding. Fungi have the following characteristics:
i) They have a cell wall.
ii) They have a nucleus.
iii) They have no chloroplasts.

(d) Organism Y is Hydra.

Explanation: Hydra is a genus of small fresh-water animals

(e) Yeast ( X) is a unicellular and Hydra (Y) is a Multicellular.

Explanation: Yeasts are unicellular organisms because they are single-celled organisms.
Hydra are multicellular organisms with complex bodies

P is Amoeba ; Q is Pseudopodia ; R is Binary fission ; S is Paramecium.

(a) Animal A is Frog and form is Tadpole.

(b) The change from Tadpole to Frog is called as Metamorphosis.

(c) Since, A is Frog, hence the breathing organ of Frog is Lungs.

(d) Since, B is Tadpole. The breating organ of Tadpole is gills.

(a) General Name of Animals Like X is Oviparous. Oviparous animals are those which reproduce by laying eggs. The young ones develop inside the eggs.

(b) Examples of Animals like X are Frog, Fish and Star Fish etc.

(c) General Name of Animals Like Y is Viviparous. Viviparous animals are those animals in which the young ones develop inside the uterus of the mother.

(d) Examples of Animals like Y are Human beings, cattle, etc.

(a) A is Mosquito; B is Larva; C is Metamorphosis; D is plasmodium

(b) Butterfly is another insect which also undergoes metamorphosis.