This is a marine habitat of today: a reef at Eniwetok, an atoll in the Marshall Islands. Coral reefs provide habitats for a staggering number of life forms.

Here are some other common forms of modern marine life:

Eniwetok reef photo by Dr. James P. McVey, NOAA Sea Grant Program; Scallop (Chlamys sp.) by E. Eugenia Patten, © 2001 California Academy of Sciences; Sea urchin and starfish courtesy of Roy Caldwell, UCMP; Octopus and Hawksbill Turtle (Eretmochelys imbricata) by Eugene Weber, © 2001 California Academy of Sciences; White-knight Nudibranch (Archidoris odhneri) and Aggregating Sea Anemone (Anthopleura elegantissima) by Gerald and Buff Corsi, © 1999 California Academy of Sciences.