Therefore, limestone outcrops that we see on land today must indicate that this piece of land was once under water and took millions of years to form. Still another example is plate techtonics . We know that the continents and oceans sit on plates of the earth's crust that move around on top of the molten mantle. When plates collide, they can form huge mountain ranges like the Himalayas or the Andes. Indeed, through advanced isotope dating of rock minerals, we know that the earth is about 4.6 billion years old.
Slow processes can cause large changes over a long periods of time.
These observations led Darwin to suppose, like earth's geological system which changes slowly through time to produce big changes in geological features, that earth's biological system must undergo similar changes. Somehow, there must be slow processes that lead to the formation of new species and that, over time, these processes have created the Darwin's questions about evolution were so fundamental that many still remain unanswered. In 1831, Darwin set sail on a 5-year trip around the world as an unpaid naturalist aboard a British survey ship, the Beagle. He used the trip to gather evidence for his theory of evolution. In other words, two temparate tree types growing in the same environment in Chile and England were less likely to be related than than the tree in Chile and a tropical tree in Peru.