Evolution (PCB 4674). Chapter 2. The evidence for evolution

EVOLUTION/LECTURE1
in the Andes in South America, the Alps of Europe, and the Grand Canyon of
America's arid southwest. These observations suggest that the Earth itself has changed
over time. Habitats have changed in location and character throughout the course of
history. Landforms and habitats are continuously being modified, just as species are
4.- The age of the Earth
4.1.- The Theory of Special Creation establishes that the Earth is about 6,000 years old.
However by the time of Darwin geological evidence was mounting that the Earth was
much older.
4.2.- Using the technique of relative dating geologists have established the chronology of
relative dates known as the geologic time scale (Fig. 2.11). They also created the concept
of the geological column, which is a geologic history of the Earth based on a composite,
older-to-younger sequence of rock strata. Geologists began working in time scales of millions
of years, instead of a few thousand years
Figure 2.11.: The geological time scale. The sequence of eons,
eras, periods, and epochs shown on the left part of this diagram
was established through the techniques of relative dating. Each
named interval of time is associated with a distinctive fossil flora
and fauna. The absolute ages included here were added much later,
when radiometric dating system became available. The abbreviation
Ma stands for millions of years ago
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