Viviparous and Oviparous Animals and Plants Tnpsc

Directly giving birth to young ones are vivipary animals. Vivipary means placental mammals. The young ones directly receive food and oxygen from the mother through the Placenta.

Oviparous Animals

The animals that lay eggs laden with the yolk are called Oviparous. The embryonic development takes place outside the body of the mother called Oviparous Animals.

The land-dwelling animals lay eggs outside after the process of internal fertilization with the shell is called cleidoic eggs. Examples are reptiles and insects such

The animals having embryos develop inside the eggs that are retained within the mother s body are nourished by the egg yolk and there is no placental connection called ovoviviparous animals. An example of ovoviviparous animals is Vipers.

The young one has to pass through morphological anatomical and physiological changes to transform into adults are known as metamorphosis.

The outer skin is cast off periodically in insects and this process is known as moulting or ecdysis. The larval stages between two successive moulting are called stadia. The insects grow by a series of changes and growth stages are called instars.

The hormone s secreted by the neurosecretory cells of the brain and controls moulting in insects is known as moulting hormone or ecdysone or juvenile hormones. The 2 types of metamorphosis are incomplete and complete metamorphosis.

An example of incomplete metamorphosis is Grasshopper. The example complete metamorphoses are Butterfly and silkmoth.

The life cycle of Grasshopper is Eggs>Nymphs>Adults.

The life cycle of butterfly are Eggs>Larva>Pupa>Adult.

The newly hatched young ones resemble the adult except in size, lack of wings and reproductive organs, the young ones (nymphs) undergo several intermediary stages through successive moulting to become an adult is the incomplete metamorphosis.

The young ones are strikingly different from the adults and the process of development starts with larva which hatch out of the egg to adult is the complete metamorphosis. The larva that hatches out of the eggs is worm-like termed as Caterpillar.

Oviparous Plants

When seeds develop after detaching from the plant it is known as oviparous plants. Example: Mango, coconut, etc.

Viviparous Plants

When seeds develop before detaching from the plant, it is known as viviparous plants. For example, Rhizophora, etc.

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* * All the Notes in this blog, are referred from Tamil Nadu State Board Books and Samacheer Kalvi Books. Kindly check with the original Tamil Nadu state board books and Ncert Books.
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