People have always wondered how life originated, and how so many different kinds of plants and animals arose. Stories of a supernatural creation of life developed among many people. While in late 17th century many believed in ‘Abiogenesis’, the process by which a living organism arises naturally from non-living matter.
According to that it is believed that flies born from putrid matter, mice from dirty hay, and crocodiles from rotting logs at the bottom of bodies of water, and so on. The first serious attack on the idea of spontaneous generation of life was made in 1668 by Francesco Redi, an Italian scientist, who proved that maggots did not arise spontaneously in decaying matter, as commonly believed, but from eggs deposited there by flies.
Proving it furthermore, that microorganisms are not generated spontaneously came in the 1860s, when Louis Pasteur, a French scientist did a remarkable experiment. He filled a long-necked flask with meat broth (meat stock). He then heated the glass neck and bent it into an “S” shape. Air could reach the broth, but gravity acted to trap airborne microorganisms in the curve of the neck. He then boiled the broth. After a time, no microorganisms had formed in the broth. When the flask was tipped so that the broth reached the microorganisms trapped in the neck, the broth quickly became cloudy with microscopic life. Therefore, Pasteur disproved ‘Abiogensis’.
Rise of ‘cell’
Now it is believed that over many millions of years, as the ingredients of life; amino acids, proteins, lipids and other molecules splashed around in the ‘primodial soup’ possibly helped by lightning strikes, they formed the first cells. A cell is a basic unit of life. They are tiny packets, or bags, of organelles, or tools, needed for the cell to survive. Even our bodies today composed with trillions of cells. A cell s’ major components are nucleus (where the genetic components are located), Mitocndria to produce energy and cytoplasm (a fluid component of the cell, where all the other organelles floats within). A cell can eat, move around, and reproduce. These cells took the chemicals of life found in the soup and put them together inside protective sacks.
These first cells were very simple and because there was little or no oxygen available, they probably did not need it to survive. As strange as it may seem, the first cellular life forms on Earth probably depended on the ‘primodial soup’. At that time, there were plenty of proteins, amino acids, and lipids to go around. The first cells were probably all consumers, the ancestors of animals.
Over millions of years’ time, food supplies began to diminish. As a result, new types of cells had to form. These cells were called producers. Producers evolved the ability to actually create their own food, using the chemicals around them and the energy from the Sun, or from heat found in the Earth.
These producers would be ancestors to the plants. From very simple cells, to multi-cellular life forms, life had a long way to go. A number of very important changes allowed life to become today’s advanced forms. The first important advancement was the development of cells that use oxygen. The first cells could not use oxygen because there was not enough of it in the air. However, as these first cells started dealing with life, they released oxygen into the atmosphere. Over a very long period of time, earth s’ atmosphere changed from a poisonous and deadly mix of gases to the life friendly atmosphere today.