Early Life Part I: The Forming of the First Cells

Cells are made of proteins, but how did the first cells form? Scientists think that 3800 million years ago the gasses that poured out of the volcanoes that covered the Earth dissolved in the warm water of the oceans. Then, they speculate, these chemicals reacted with each other to form more complex chemicals, like the ones that make up proteins. (1)


1. Representation of the 3D structure of an example of a protein.

Although scientists have a fairly good theory about how the first proteins may have formed, they don’t have a good theory about the forming of the first living cells. The first cells may have formed in the seas. The theory is that films of proteins, floating on the water, may have broken up to form tiny spheres with chemicals trapped inside. Another theory is that cells may have formed around water springs. The proteins may have melted together and then formed tiny, cell-like spheres as they cooled. Another idea is that the clay at the bottom of the shallow seas helped tiny blobs of protein to stick together and form some of the chemicals found in cells. (1)

The first living cells were single cells, a lot like bacteria. Millions of years later, some bacteria, known as blue-green algae, began to use sunlight and water to make their food and so photosynthesis was born. It’s these blue-green algae of which we have fossils. These fossils are remains of large groups of blue-green algae and are called stromatolites. Some of them are over 3500 million years old. (1) Stromalites still exist today in shallow seas. (2)


2. Pre-Cambrian fossil stromatolites in the Siyeh Formation, Glacier National Park.

A possible even older trace of life was found in Greenland. Scientists there discovered traces of a type of carbon in 3.8 billion years old rock. It’s possibly a trace of early microbial life. (2)



References:

1. The Usborne Internet-Linked Encyclopedia of World History, p. 24, 25, 2002
2. Ackroyd, Peter, The Beginning, p. 14, 2003, Dorling Kinderley, London

Picture credits:

1. Taken from the Wikipedia Commons
2. Taken from the Wikipedia Commons