Internal Fertilization

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The process in which there is a fusion of sperm with the egg also known as the Ovum to produce Zygote is called Fertilization. It is the vital and primary stage of sexual reproduction. Fertilization can be external or internal. 

What is Internal Fertilization?

For sexual reproduction, male penis insertion into the vagina of a woman is important. A male inserts his penis into the vagina of a woman, after which the penis secretes sperm into the female reproductive tract to fuse with the egg. If the fusion takes place within the female parent, that is known as an Internal Fertilization. In both humans and animals, the fusion of gametes takes place internally. In internal fertilization, a zygote is formed within the mother and gets its nourishment from her.

There are Three Ways in Which Internal Fertilization Produces Offsprings:

  • Oviparity

  • Ovoviviparity

  • Viviparity

Oviparity

The fertilized eggs are laid outside the body of the mother. The egg receives nourishment from the yolk. Some examples of oviparous are fish, amphibians, reptiles, etc. 

Ovoviviparity

The fertilized eggs are retained in the female, and the embryo receives nourishment from the yolk. When they hatch, the young ones are fully developed. This is seen in some bony fish, sharks, lizards, snakes, etc.

Viviparity

In this, the young one develops inside the mother and receives nourishment through the placenta. Most of the mammals, a few reptiles, and cartilaginous fish are viviparous.

Advantages of Internal Fertilization

The advantages of internal fertilization are:

  • Chances of fusion of gametes are more.

  • The probability of successful fertilization is increased.

  • The mates are selective.

  • The chances of dehydration of gametes decreases.

  • The young one is protected against predators and the outside environment and hence chances of survival are increased.

Internal Fertilization in Humans

The fertilization in humans is internal. The male introduces the sperms into the female reproductive tract. The sperm fuses with the egg in the ampulla of the fallopian tube. This results in the formation of a zygote that undergoes mitosis to form an embryo. The embryo is then implanted into the uterus. The entire process of development of the child takes place inside the uterus. Once the child is completely developed, it is delivered. However, with Internal fertilization, there is a high risk of sexually transmitted diseases in individuals. But, at the same time, it is also considered to be one of the most favorable methods of fertilization. 

FAQ (Frequently Asked Questions)

Q1. Define Fertilization.

Ans - The process in which there is a fusion of sperm with the egg also known as the Ovum to produce Zygote is called Fertilization. It is the vital and primary stage of sexual reproduction. Fertilization can be external or internal. 

Q2. What are the Advantages of Internal Fertilization? 

Ans. - The Advantages of Internal Fertilization are:

  • Chances of fusion of gametes are more.

  • The probability of successful fertilization is increased.

  • The mates are selective.

  • The chances of dehydration of gametes decreases.

  • The young one is protected against predators and the outside environment and hence chances of survival are increased.

Q3. Explain Internal Fertilization in Humans.

Ans - The fertilization in humans is internal. The male introduces the sperms into the female reproductive tract. The sperm fuses with the egg in the ampulla of the fallopian tube. This results in the formation of a zygote that undergoes mitosis to form an embryo. The embryo is then implanted into the uterus. The entire process of development of the child takes place inside the uterus. Once the child is completely developed, it is delivered. However, with Internal fertilization, there is a high risk of sexually transmitted diseases in individuals. But, at the same time, it is also considered to be one of the most favorable methods of fertilization.

Q4. What are the Three Ways in Which Fertilization Takes Place in Animals? 

Ans - There are Three Ways in Which Internal Fertilization Produces Offsprings:

  • Oviparity

  • Ovoviviparity

  • Viviparity

Oviparity

The fertilized eggs are laid outside the body of the mother. The egg receives nourishment from the yolk. Some examples of oviparous are fish, amphibians, reptiles, etc. 

Ovoviviparity

The fertilized eggs are retained in the female, and the embryo receives nourishment from the yolk. When they hatch, the young ones are fully developed. This is seen in some bony fish, sharks, lizards, snakes, etc.

Viviparity

In this, the young one develops inside the mother and receives nourishment through the placenta. Most of the mammals, a few reptiles, and cartilaginous fish are viviparous.

Q5. What are the Risks of Internal Fertilization?

Ans - In Internal fertilization, there is a high risk of sexually transmitted diseases in individuals. But, at the same time, it is also considered to be one of the most favorable methods of fertilization. 

Q6. What is the Process Followed for Reproduction in Humans? 

Ans - In sexual reproduction, male penis insertion into the vagina of a woman takes place. A male inserts his penis into the vagina of a woman, after which the penis secretes sperm into the female reproductive tract to fuse with the egg. If the fusion takes place within the female parent, that is known as Internal Fertilization which leads to further reproduction.