Fertilization
Fertilization, as you already know, is the moment in
which a male sex cell, a sperm, unites with a female sex cell, the ovule. As a result of their union a zygote is formed
in the womb of the female. The division and growth of the zygote leads to the
birth of the new individual.
Unlike humans, in animal reproduction, there are two
mechanisms by which fertilization can take place: Internal and external.
Internal.- the eggs are
fertilized inside the female reproductive tract.
Vertebrate animals such as reptiles, birds, mammals, an most insets, do not return to water to mate, so the male must place the sperm cells directly inside the female body. The result is that land animals have developed complicated mating behavior which involves dances, smells and often very colorful mating exhibitions.
It is usually the male which is colorful in the animal world, in order to attract a mate. Peacocks are stunning example of the difference between male and female. The male has bright, showy tail feathers. The female has short tail feathers and lacks the beautiful colors of the male.
External.- the eggs
are fertilized outside of the body
External fertilization – Spawning
Some aquatic animals, like frogs, toads, and most
fish, release their eggs and sperm into the water where they meet and are fertilized.
This process is called spawning.
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