Animal Life Cycles
While humans and birds are born looking like small versions of adults, some animals undergo drastic changes in shape and structure during their life. This is called Metamorphosis.
1. Life Cycle of a Mosquito
Mosquitoes breed in stagnant water.
Stages
- Egg: Laid on stagnant water.
- Larva: Worm-like, active swimmer, comes to surface to breathe.
- Pupa: Comma-shaped, active but does not feed.
- Adult: Wings develop, flies away.
Warning
Prevention: Since larvae and pupae need to breathe air at the water surface, adding a thin layer of kerosene oil to stagnant water blocks the air, killing them. This prevents mosquito breeding.
2. Life Cycle of a Frog
Frogs show a transition from living in water (aquatic) to living on land and water (amphibian).
Stages
- Spawn (Eggs): Cluster of jelly-like eggs in water.
- Embryo: Developing inside the egg.
- Tadpole (Early): Has a tail for swimming, breathes through gills. No legs. Herbivore.
- Tadpole (Late): Develops hind legs.
- Froglet: Tail shrinks, lungs develop, front legs appear.
- Adult Frog: Tail disappears completely. Lives on land/water.
Key Differences
- Tadpole: Aquatic, has tail, no legs (initially), breathes via gills.
- Frog: Amphibious, no tail, strong legs for jumping, breathes via lungs/skin.