1) Approximately 6 billion years ago, the Earth formed from a part of the sun that cooled and separated. While the interior remains hot, tectonic forces later caused hills, mountains, and changes to the surface. 2) Around 4 billion years ago, the cooled Earth developed water and an atmosphere, allowing the first living single-celled organisms to form in oceans about 3.5 billion years ago. 3) Multicellular life eventually emerged, followed by more complex organisms like fish, amphibians, reptiles, birds, and later humans. Periods like the ice age were challenging as many species went extinct while others survived.

1. PSYCHOLOGY EVOLUTION OF EARTH & LIFE ON EARTH

2. EVOLUTION OF EARTH About 6 billion years ago, a glowing part of the sun in the form of a fiery ball of fire separated from it. Gradually it cooled down and formed the present planet earth. However the interior of the earth is still burning hot.

3. EVOLUTION OF EARTH Due to tectonic forces, hills and mountains formed on the earth. During the early period earth could not support life. The surface was hot and the atmosphere was filled with gases of various kinds

4. EVOLUTION OF LIFE ON EARTH About 4 billion years ago, the earth cooled sufficiently to permit water to condense and form rivers, lakes, seas. About 3.5 billion years ago, certain gases in the atmosphere came together and formed the first living form in water.

5. FIRST LIVING BEINGS The first living beings were single celled organisms. Later during the course of time other multi-cellular forms emerged from the single-celled organisms.

6. HIGHER ORGANISMS Gradually organisms with complex body organisation like fishes, amphibians, reptiles, birds and other animals including humans emerged.

7. GLACIAL AGE During the glacier age or ice age climate was not suitable for the survival of many organisms. The organisms that could not survive became extinct and only the fittest survived and continue to exist.

8. PROCESS OF CHILD BIRTH IN HUMANS The process of childbirth starts from the moment of fertilization (a sperm from the male fuses with the egg of the female) and results in the embryo developing into a foetus.

9. STAGES OF FOETUS FORMATION Fertilization and zygote formation Implantation of embryo and its development Placenta formation Child birth