How life began on earth? Well it can be explained in two things. First, by religious creation. Second, the famous theory of evolution.
Religious creation was based on the Holy Bible,God's word. The Bible explained that after God created the world, he created the first male and female named Adam and Eve. They were made in the image and likeness of God, and they were created to rule all of Gods creation on earth. Adam and Eve have intelligence, free will and spirit, the other creatures have none, they were made to serve man and mankind was made to serve God, however Adam and Eve disobeyed God and became sinners.
The Theory of Evolution was first proposed by Charles Darwin. He believe that Man was a product of evolution beginning from apes. He said that apes was the ancestor of mankind, that belief was just a theory and not a positive scientific fact.