We have a very brief time here on Earth, so limited in fact
that there are certain events that we have no possibility of perceiving. The planet itself is a giant dynamic system
that moves and shapes itself into continents, mountain ranges and expanses of
ocean. Unfortunately we don’t notice any
of this stuff happening in front of us because we are not around long enough to
see it unfold (in any significant way).
From birth to death the overall composition of the Earth is pretty much
the same. North America is an ocean away
from Europe to the east and an ocean away from Asia to the west and has been
for a really, really long time.
While we can’t see the movements of the Earth in our
lifetimes there are ways we can know that the continents have been otherwise arranged
in the past. Many people look at the
world map and recognize that the continents look like they could fit together like
a jigsaw puzzle. In fact the continental
boundaries that look like they fit together show evidence that at one point
they really did. As one example, similar
rock layers and even fossils are found on the edges of separated continents
where the land used to meet. Modern laser
guided, space based measurements show that continental movement is measured in
centimeters per century so it is no wonder that we can’t see it happening in
front of us.
Evolution faces a similar challenge because it occurs over extremely
long periods of time. When we look
around we see a collection of animals, plants and other organisms that seem to
always be the same. Really in terms of
the short time we are on Earth the collection of animals, plants and other
organisms are pretty much the same.
It takes a really long time for change to accumulate in a population just like
it takes a really long time for an entire continent to drift thousands of miles
away from land it used to be connected to. But just because there are
challenges to observing super long term events doesn’t mean they haven’t
happened or that they can’t be detected.
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