Human Evolution
- Vertebrates appear about 500 million years ago
- Land plants appear about 400 million years ago
- Insects develop about 300 million years ago
- Dinosaurs appear about 200 million years ago
- Birds appear about 150 million years ago
- Mammals and birds well established by 100 million years ago
- Primitive human beings appear by 3 to 4 million years ago
- Modern humans (Homo sapiens) appear during last 90,000 years