Most mammals have deciduous teeth, otherwise known as baby teeth or milk teeth. The technical term for this is "dental replacement." Animals that have only two sets of teeth in a lifetime are called "diphyodonts." More than two and they are called "polyphyodonts." We mammals are diphyodonts. The species which gave rise to humans also had baby teeth and humans continue to have baby teeth.
Most babies aren't born with any visible teeth in their mouth as they are not required for few months as babies rely on mother's milk in that period. The baby teeth begin poking after 6 months till 2 years. They play a very important role in preserving space for our adult teeth until they can grow up underneath.
The reason we don't simply grow a singular set of teeth is that our jaws are just not large enough to accommodate the number and size of our adult teeth right away (we wouldn't want our jaws to be large enough either because giving birth would be near impossible). While our adult teeth are busy forming underneath our gums inside our jaws, our baby teeth keep space available so that adult teeth can erupt normally into our mouths. By distributing chewing forces into our jaws they aid in the development of those bones. They also make the process of adult teeth erupting much more organised since baby teeth are holding their place in line for them. Our baby molars are the most important teeth in this process because they are much wider than the adult teeth that grow to replace them.
References:
https://www.quora.com/What-is-the-evolutionary-advantage-of-deciduous-teeth-in-many-mammals
PC : http://www.safbaby.com/wp-content/uploads/2015/10/smile-with-baby-teeth.jpg
Most babies aren't born with any visible teeth in their mouth as they are not required for few months as babies rely on mother's milk in that period. The baby teeth begin poking after 6 months till 2 years. They play a very important role in preserving space for our adult teeth until they can grow up underneath.
The reason we don't simply grow a singular set of teeth is that our jaws are just not large enough to accommodate the number and size of our adult teeth right away (we wouldn't want our jaws to be large enough either because giving birth would be near impossible). While our adult teeth are busy forming underneath our gums inside our jaws, our baby teeth keep space available so that adult teeth can erupt normally into our mouths. By distributing chewing forces into our jaws they aid in the development of those bones. They also make the process of adult teeth erupting much more organised since baby teeth are holding their place in line for them. Our baby molars are the most important teeth in this process because they are much wider than the adult teeth that grow to replace them.
References:
https://www.quora.com/What-is-the-evolutionary-advantage-of-deciduous-teeth-in-many-mammals
PC : http://www.safbaby.com/wp-content/uploads/2015/10/smile-with-baby-teeth.jpg
