An alarming message about deodorant use and breast cancer began circulating on the Internet in the 1990s, spread via e-mail and message-board postings. It continues to resurface now and again and causes a great deal of concern about the safety of items many of us use every day. So let's take a look at the evidence.
How long have sharks been in existence? A: Geological records show that modern shark species have existed for between 201 million and 174 million years. Earlier fish species similar to sharks existed as early as between 419 million and 359 million years ago.
Life Cycle of Sharks. Sharks have been the most feared and wild marine creatures. These animals have been prowling in the oceans for around 400 million years and have evolved into 440 different species. Sharks are known to live for many years.