State differences between internal and external fertilisation?


  Internal fertilization  External fertilization
Fertilization occurs inside the female's body Fertilization occurs outside the female's body
Sperms are ejaculated in the form of fluid in  female's body which then combines with egg.The male releases sperm cells onto the eggs which are laid external to the female's body.
Mostly occurs in terrestrial animals and humansMostly occurs in amphibians and aquatic animals.
The number of sperms and eggs produced is  comparatively lessThe number of sperms and eggs produced is more in comparison to internal fertilization.
Example: Human beings, Birds

Example: Fishes, Frogs



@ Lakshya :- Good work, Keep contributing !!

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Internal fertilization takes place inside the body of the female. It is necessary for animals which live on land (terrestrial animals) and is retained by aquatic animals descended form terrestrial ancestors eg whales and dolphins. 
External fertilization takes place outside the body of the female. It usually takes place in water, usually the environment in which the animal lives eg fish and amphibians. This is because eggs and sperm would dry out and die if they are not kept wet. 
Internal fertilization is more certain than external fertilization so fewer eggs need to be produced. 
After internal fertilization eggs can be protected and fed while developing inside the mother's body. After external fertilization the eggs are potentially exposed to predators and so must either be produced in very large numbers or protected by the parents or both.

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 There is a difference. Internal feritilisation takes place in the female's body while external fertilisation does not. External fertilisation usually requires a medium such as water, which the sperms can use to swim towards the egg cell. External fertilisation usually occur in fish and amphibians. Internal fertilisation occurs in mammals, insects, birds, reptiles.

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 External fertilization is a form of fertilization in which a sperm cell is united with an egg cell external to the body of the female. Thus, the fertilization is said to occur "externally". This is distinct from internal fertilization where the union of the egg and sperm occur inside the female after insemination through copulation.

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 Internal Fertilization

The fertilization process occurs within the body of a female is called internal fertilization. It is a specialization for the protection of egg, but it depends on the birth method . Reptiles and birds have thick shell, covering the egg to protect it from dehydration and destruction. However, fertilization occurs inside the body otherwise, sperm has to enter through a thick wall.

Animals such as mammals also have internal fertilization, where embryo develops inside mother, which enhances the protection to the embryo1.

Internal fertilization facilitates the survival of the embryo, selective fertilization, and longer protection and minimizes the wastage of gametes.

External Fertilization

In external fertilization fusion of sperm and egg occurs externally of the female body. External fertilization needs water to facilitate their fertilization, so it occurs in wet environments. Female and male gametes are released to the water, and male gamete is mostly mobile. This type of fertilization can be seen in lower plants. The advantage of external fertilization is that it produces a large number of offspring due to the external hazards. So survival of the embryo is comparatively lower. Amphibians and fish are examples for these types of animals.

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The fertilisation which takes place inside the body of a female is called internal fertilisation. Internal fertilisation in cludes mammals suvh as h 

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The fertilisation which takes place inside the body of a female is called internal fertilisation. Internal fertilisation takes place in mammals such as human beings, birds and reptiles.

 The fertilisationwhich takes place outside the body of a female is called external fertilisation. In this fertilisation female,s eggs are fertilised outside the body of a female. External fertilisation takes place in amphibians such as toads, fishes and frogs.

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