Q) Which of these have been on Earth longer - sharks or trees?
A) According to the Smithsonian Magazine - (http://www.smithsonianmag.com/smart-news/respect-sharks-are-older-than-trees-3818/?no-ist),
Sharks have been on Earth nearly 50 million more years than trees. The
first known tree lived around 350 Million years ago in what is now the
Sahara Desert. Sharks have been around 400 Million years, skirting four
global mass extinctions.