== == There is evidence that coral first appeared during the early Cambrian period
(which began about 542 million years ago). This evidence is very scarce so far and it is believed that it was not until the Ordovician Period (which began when the Cambrian period ended, about 488 million years ago) that "...mineralized corals became important parts of marine ecosystems.1"
For a history of ancient coral and other early marine life, see:
Anthozoa: Fossil Record
http://www.ucmp.berkeley.edu/cnidaria/anthozoafr.html
For an interesting article on some specific types of ancient corals, see: Margaret Fuller, Richard Jenkins, Reef Corals From The Lower Cambrian Of The Flinders Ranges, South Australia, Palaeontology Volume 50 Issue 4 Page 961-980, July 2007.
1Anthozoa: Fossil Record
http://www.ucmp.berkeley.edu/cnidaria/anthozoafr.html
The length of a day 500 million years ago was about 21 hours.
500 billion years ago, planet Earth didn't exist. The Universe didn't even exist for such a long time; the age of the Universe is estimated at about 14 billion years.500 billion years ago, planet Earth didn't exist. The Universe didn't even exist for such a long time; the age of the Universe is estimated at about 14 billion years.500 billion years ago, planet Earth didn't exist. The Universe didn't even exist for such a long time; the age of the Universe is estimated at about 14 billion years.500 billion years ago, planet Earth didn't exist. The Universe didn't even exist for such a long time; the age of the Universe is estimated at about 14 billion years.
The Earth is 4.5 billion years old. Life has been around for 3.5 billion years. Complex life forms originated about 500 million years ago. There is no telling if/when life will cease to exist on Earth or if/when it will be destroyed in space.
Jellyfish have been around for 500 million years.Jellyfish have roamed the seas for at least 500 million years.
Pterodactylus fossils date to between 150.8 and 148.5 million years ago. Thus, they existed for about 2.3 million years.
500 years ago, Turkey as a country did not exist. The modern day geographical region was part of the Ottoman Empire.
aquatic
500 million years
is true or false, fossils suggest that birds have been on earth for more than 500 million of years
1 billion
Clams have been around for about 500 million years.
Jellyfish have roamed the seas for at least 500 million years.