Source: Genesis 1 and 2
In the beginning, the world and all living things that we know about today did not exist. The world was shapeless and dark. However, God did exist, and one day God said "Let there be light: and there was light". God saw that His work, the newly created light, was good. God separated the light from the darkness, and He called the light Day. God called the darkness Night. This first period of light and darkness was the first day of Creation.
On the second day, God separated the waters of the world by a space. This space was the atmosphere. The waters below the atmosphere formed the basis for the seas and the earth. The waters above the atmosphere formed a great canopy over the world.
On the third day, God gathered the waters below the atmosphere into one place. This allowed dry land to appear, and God called this dry land Earth. God called the waters that were gathered together Seas. God saw that His work, the newly created Earth and Seas, was good. Then, God created the trees and the plants and the grass and caused them to grow upon the Earth. God saw that this was good also.
On the fourth day, God created the sun and the moon and the stars. Along with the Earth, God set all of these celestial bodies in motion, orbiting and spinning, and moving, so that there would be seasons, and days, and years. God saw that this was good.
On the fifth day, God created the birds that fly in the air. He created eagles and doves, hawks and cardinals, owls and ravens. He created them all. God also created the fish and the whales, all sorts of animals that live in water, and the waters were teeming with these new creatures. God saw that this was good. Then God blessed these new creatures and told them to "Be fruitful, and multiply" and to fill up the air and the waters of the world.
On the sixth day, God created the creatures that live on the dry Earth. He created cattle, lions, dogs, bears, and even the dinosaurs. He created them all. God saw that this was good. Then God created man and woman, who were Adam and Eve. God gave Adam and Eve dominion over all the world and the creatures in it. God then blessed them and told them to "Be fruitful, and multiply".
And after all this, God saw everything that he had created, and it was all very good. On the seventh day God rested, and blessed the seventh day of the week forevermore as a day of rest.