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Life on Earth

The Earth is very unique to our universe because it is the only planet known to have life . Our planet is the right distance from the sun so that it is possible for animals and plants to live. The first signs of life were blue-green algae and bacteria formed in the seas, and did not appear until 3.5 billion years ago. More complex plants and animals did not develop until 570 million years ago. There are about 1.3 million species of animals on Earth today and probably millions more that are unknown.


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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA