And you know what will come out when it hatches. A caterpillar! And then the caterpillar forms a cocoon and after some time out comes a pretty butterfly.
We all know the life cycle of a butterfly. It is special because after each step a completely different life form emerges, very different from the previous step. It is also called "metamorphosis". A complicated sounding name, to match the complicated process.
But why does a butterfly egg hatch on to a caterpillar in the first place? Why does it not hatch directly into a butterfly? It indeed is a big question. But let's try and understand it in a simple way.
Forming a new life is complex affair. Nothing gets created out of thin air, it takes lots of energy. Creating bigger things take even bigger amounts of energies. So to keep things easy, life starts small. The energy and nutrition required to create this small new life can be capsuled easily. Eggs, seeds, fruits are all examples of this. After this small new life gets born, it eats food to grow into an adult. We are familiar with this. Even we ourselves are born small and grow to become adults.
Butterflies are little different because they lay many many eggs. Since the energy and nutrients get divided among the eggs, each egg gets only a small portion of it. So the butterfly eggs have been designed to be very simple. They use the small amount of energy with them to hatch out a simple life form - the caterpillar.
This simple caterpillar is designed to do just one thing - eat. It eats and eats till it becomes fat and large and has enough energy to create the final butterfly form. It then forms a cocoon around itself - a sort of an egg that it creates for itself. All the energy it had absorbed are now used to change itself into a far more complex life form - the butterfly!
Here are a few more things for you to ponder on:
- Why do some insects lay many many eggs?
- Why don't animals go through metamorphosis as well?
- Why is a cocoon required?