Geology Reference
In-Depth Information
The combination of information from scientific specialists including geneti-
cists, biologists, and paleontologists (who study fossil remains of organisms) is
called
the modern synthesis
or
Neo-Darwinian evolution.
Modern biological research in particular has shown that while life on earth is very di-
verse, all living organisms share certain basic characteristics. For example, all life is
composed primarily of four elements: carbon, nitrogen, hydrogen, and oxygen. And all
living things have DNA, in chromosomes, that are passed on during reproduction.
These similarities suggest that the wide variety of living things currently existing on
earth share a very, very distant common ancestor.
Putting Evolution to the Test
The geologic record — specifically
fossils,
the preserved remains of once-living organ-
isms — provides an active laboratory to ask and answer questions about evolution.
Based on the theory of evolution, scientists can make predictions about what they ex-
pect to find in the fossil record, and then they test their predictions by gathering eviden-
ce from the rocks.
Here are examples of some predictions based on the theory of evolution that
can be tested with the fossil record:
If evolution has taken place, the oldest rocks should have remains of organisms
very different from organisms today.
If organisms today are descended from organisms in the past, there should be in-
termediate fossil forms of organisms that link the two.
If evolution occurred, organisms that appear related today should have a common
ancestor in the fossil record and show increasing differentiation from that ancest-
or through time to the present.
Keep reading through the rest of Part V to find out how each of these predictions has
been proved true by fossil evidence in the geologic record.
