In biology, evolution is the process by which populations of organisms acquire and pass on novel traits from generation to generation. Its occurrence over large stretches of time explains the origin of new species and ultimately the vast diversity of the biological world. Contemporary species are related to each other through common descent, products of evolution and speciation over billions of years.
The basic timeline is a 4600 million year old Earth, with approximately:
4000 million years of simple cells (also known as single-celled organisms),
3000 million years of photosynthesis,
2000 million years of complex cells,
1000 million years of multicellular life,
600 million years of simple animals,
570 million years of arthropods
550 million years of complex 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,
300 million years of reptiles,
2007-05-23
21:17:35
·
10 answers
·
asked by
Anonymous