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What is macroevolution?
Macroevolution generally refers to evolution above the species level.
So instead of focusing on an individual beetle species, a macroevolutionary
lens might require that we zoom out on the tree of life, to assess the diversity of the entire beetle clade and its position on the tree.
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| Macroevolution refers to evolution of groups larger than an individual species. |
The history of life, on a grand scale. |
Macroevolution encompasses the grandest trends and transformations in evolution, such as the origin of mammals
and the radiation of flowering plants. Macroevolutionary patterns are generally what we see when we look at the large-scale history of life.
It
is not necessarily easy to "see" macroevolutionary history; there are no firsthand accounts to be read. Instead, we reconstruct
the history of life using all available evidence: geology, fossils, and living organisms.
Once we've figured out what evolutionary events have taken place, we try to figure out how they happened. Just as
in microevolution, basic evolutionary mechanisms like mutation, migration, genetic drift, and natural selection are
at work and can help explain many large-scale patterns in the history of life.
The basic
evolutionary mechanisms — mutation, migration, genetic drift, and natural selection — can produce major evolutionary change
if given enough time.
A process like mutation might seem too small-scale to influence a pattern
as amazing as the beetle radiation, or as large as the difference between
dogs and pine trees, but it's not. Life on Earth has been accumulating mutations
and passing them through the filter of natural selection for 3.8 billion
years — more than enough time for evolutionary processes to produce its
grand history.
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