The earth's first primordial life developed in the Hadeon Eon. This life was mostly prokaryotic so they had no distinct nucleus or organelles. In the Acheon Eon Cyanobacteria developed. As mentioned before this greatly increased oxygen content in the atmosphere. That allowed for animals to develop on land down the line.
The Preterozoic Eon was full of evolution and diversity in life. The first Eukaryotic Cells appeared around 1BYA. Eukaryotic Cells had nucleus and organelles. Modern day multi cellular life contains Eukaryotic Cells. So did fauna which were first found as fossils in this Eon. Around this time the ozone formed which paved the way for the Cambrian Explosion.
The Cambrain was the most rapid and largest diversification of life in Earth's History. Green plants began to appear on lad since the ozone protected them from UV radiation. In the Silurian Period the first vascular plants appeared. This allowed plants to grow taller since more water could be circulated. This was how the first trees came to be.
In the Devonian Period, life evolved even more. Seed bearing plants appeared such as ferns. Insects appeared too with huge wings. The fish that evolved in the ocean began to go on land. These were the first amphibians. Sharks also appeared in the ocean.
Due to increased oxygen in the atmosphere large land vertebrates and trees appear. In present day these are not here because oxygen levels decreased from then to now. Reptiles also appeared. All this evolution and diversification was undone by the Permian Extinction which eliminated 95% of species in the Permian Extinction
After the extinction the first mammals appeared. Mammals though did not take over. Dinosaurs a new type of organism did take over. Mammals were small at the time but eventually diversified and enlarged after the dinosaurs went extinct. Birds appeared and so did lizards. This is where we are now with complex and diverse life on Earth.