Evolution of life. Abstract artwork depicting the evolution of life on Earth. Earth (upper left) was born from clouds of gas and dust surrounding the Sun, which in turn was born from gas which condensed in our galaxy (upper right). Once the Earth started to cool after its formation, oceans formed, which were teeming with the basic chemical building blocks of life. From these components, first unicellular, then multicellular organisms evolved. As time progressed, larger predatory animals evolved, such as cartilaginous fish like the shark (centre). These, and the bony fish (lower frame) which evolved later, paved the way for the conquest of the land.