The universe showed up13,7 billion years ago. Our earth came on scene 4.5 billion years ago. Then, 3.4 billion years ago, life forms began. Prokaryotes were the earliest life forms. The basic timeline is a 4600 million-year-old Earth with 4000 million years of simple cells; 3000 million years of photosynthesis; 2000 million years of complex cells; 1000 million years of multicellular life; 600 million years of simple animals; 500 million years of fish and proto-amphibians; 475 million years of land plants; 400 million years of insects and seeds; 360 million years of amphibians. It took a long time for life to evolve. We showed up last. (We were and are the intended result of this current event).
Photosynthesis, which converts sunlight into energy, can come in two forms: one that produces oxygen and doesn’t. The oxygen-producing form is usually assumed to have evolved later, particularly with cyanobacteria, or blue-green algae, around 2.5 billion years ago. The photosynthesis proteins showed nearly identical patterns of evolution to the oldest enzymes, stretching far back in time, suggesting they evolved similarly. We now have a good sense of how photosynthesis proteins evolve, adapting to a changing world; we can use directed evolution to learn how to change them to produce new kinds of chemistry. We could develop photosystems that could carry out complex new green and sustainable chemical reactions entirely powered by light.
One of the earliest known humans is Homo habilis, or “handyman,” who lived about 2.4 million to 1.4 million years ago (maybe) in Eastern and Southern Africa. Cheddar Man’s genome analysis results align with recent research that has uncovered the complex nature of the evolution of human skin tone. The first humans to leave Africa 40,000 years ago are believed to have had dark skin, which would have been advantageous in sunny climates. (You were black before you became white, maybe). Homo sapiens, the first modern humans, evolved from their early hominid predecessors between 200,000 and 300,000 years ago. They developed a capacity for language about 50,000 years ago. The first modern humans began moving outside of Africa, starting about 70,000-100,000 years ago.
