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The symtoms of growth and development in the body of organism can be found in many different forms. some examples of interesting growth and development processes are metamorphosis.
1. Metamorphosis
Metamorphosis is the change of forms from one development step to the next one. Metamorphosis can be either perfect or imperfect.
Perfect metamorphosis develops in four phases, namely egg, larva, cocoon (pupa) and mature form (imago). For examples, butterfly, bee, mosquito, and fly.
In imperfect metamorphosis, individual experiences form change gradually, and it has already resembled the mature form. Hatched eggs grow into larvae which resemble mature individuals without wings. The larvae are called nymphs. This metamorphosis skips the cocoon phase. some species experiencing imperfect metamorphosis are beetles, grasshoppers, termites and aphid.
Other characteristic of metamorphosis is the occurrence of skin change (moulting) in larva phase. moulting is regulated by a hormone called ecdysone. moulting can occur several times. For examples, moulting in mosquito larva can be four times, in fruit fly can be twice, and in grasshorpper can be six times. larva development phase is called instar phase.
Metamorphosis also occurs in Amphibia (frog). The development from egg to adult frog lasts for one year.
2. Metagenesis
In the life cycle of Coelenterate, such as Obelia sp. and Aurelia sp. (jelly fish) metagenesis occurs between vegetative and generative phases. the vegetative phase is in the form of polyp, and the generative one is the form of medusa. Medusa has the shape like an umbrella, actively swims and produces gametes. Male modusa produces sperm cells, while the female one produces egg cells (ovum)
Sperm cells will be released and swim to the ovary, where the egg cells are produced. The result of the fertilization is zygote. Zygote will develop into larva which is called planula. Planula will leave the female parent and swim to find place to stick on and develop into a new polyp. Metagenesis also occurs in plants, such as mosses and ferns. The generative phase in moss and fern is called gametophyte phase, while the vegetatif phase is called sporophyte phase
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