Question

external and internal fertilization in brief

Answer 1

External fertilization is limited essentially to animals living in aquatic environments. The flagellated sperm must have fluid in which to swim, and the eggs lack a protective coat or shell and would dry out in the air. Almost all aquatic invertebrates, most fish, and many amphibians use external fertilization.
Most land animals, both invertebrate and vertebrate, use internal fertilization. In effect, the sperm cells are provided with the sort of fluid environment that is no longer available to them outside the animals’ bodies. The sperm can remain aquatic, swimming through the film of fluid present on the walls of the female reproductive tract. Once fertilized, the egg is either enclosed in a protective shell and released by the female, or held within the females’ body until the embryonic stages of development have been completed. Internal fertilization requires close physiological and behavioral synchronization of the sexes, which involves extensive hormonal control.

Answer 2

⍟⍟⍟⍟there are two different modes of fertilisation in nature⍟⍟⍟⍟

°°°°° INTERNAL FERTILISATION°°°°

>>>>>> the fertilized which inside the female body is called INTERNAL FERTILISATION.

It occurs in in mammals, human beings, birds, reptiles etc..

°°°°°EXTERNAL FERTILISATION °°°°°

>>>>>>> the fertilization with takes place outside the female body is called as EXTERNAL FERTILISATION.

---it occurs in amphibians like frogs, toads, fishes etc

<<<<<< in external fertilization the female and male gamut release the sperms and eggs in water fertilization takes place by collision between sperms and eggs..

>>>>>for example the males and females of frogs and fishes releasing sperms and eggs in water in which they live.

the sperms and collide with the action fertilized outside the female body of frog a fish .