The Evolution of Life

In its 4540 million (4.54 billion) years circling the sun, Earth has provided a home for life that has become more and more complex.

for the last 3600 million years, simple cells (prokaryotes);

for the last 3400 million years, photosynthetic cyanobacteria

for the last 2000 million years, complex cells (eukaryotes);

for the last 1000 million years, multicellular life;

for the last 600 million years, simple animals;

for the last 550 million years, bilaterians, 

animals with a front end and a back end, 

as well as an upside and a downside;

for the last 500 million years, fish and proto-amphibians;

for the last 475 million years, land plants;

for the last 400 million years, insects and plants with seeds;

for the last 360 million years, amphibians;

for the last 300 million years, reptiles;

for the last 200 million years, mammals;

for the last 150 million years, birds;

for the last 130 million years, flowers;

for the last 60 million years, the primates,

for the last 20 million years, the family Hominidae (great apes);

for the last 2.5 million years, the genus Homo (human predecessors);

for the last 200,000 years, anatomically modern humans.