Evolution of Land Animals
No one knows for sure how life began, whether life came about by an invisible man in the sky, or by what Darwin (and scientists today) predicted, that life formed from a "hot little pool" of matter and slowly evolved over time into what we know as life today. According to evolution, all life or most of it, originated from a single gene. The evolution of land animals is still studied today, including elephants, giraffes, and horses. Which are giving us greater clues to how existence started. Let us first establish that all life on earth ? both animal and plant ? is constructed of exactly the same substance: DNA.. By DNA we mean the chromosomes that are found in all living cells. The question philosophers and scientists have wondered is, then, how the first molecule arose.
Scientists believe that the earth was formed 3.5 billion years ago.
This is when it is believed that life first began. The world did not look like it does today. It contained no oxygen. It is unlikely that life cells could have risen from a world containing oxygen because it was highly reactive. Therefore, DNA molecular cells had to be oxydized. This is how we know that no new life arises today. All life on earth must be exactly the same age. Science today shows us that an elephant is just as old as a human, because each cell in our body carries the same hereditary material. The whole recipe of who we are lies hidden in each tiny cell.
Darwin is considered the father of evolution. We would not be discussing evolution if it were not for him. His theory consisted of two main points: first he proposed that all existing vegetable and animal forms were descended from...