Can someone offer a little perspective on micro- and macroevolution?

Question

As a teacher of AP biology, I know that biological evolution happens. I know that many biologists call the terms "microevolution" and "macroevolution" an artificial distinction. I agree. However, the terms are used in both the textbook I issued to my students (Solomon, Berg, and Martin's "Biology" 7th ed) and in the CliffsAP Biology study book that I have.

Solomon, Berg, and Martin describe microevolution as a shift in allele frequencies within a population (not within a species, although that would be a natural consequence, wouldn't it?) They define macroevolution as large-scale changes that result in the formation of new species, genera, families, etc.

The CliffsAP book says that microevolution includes speciation, and that macroevolution describes patterns of change in groups of related species over broad periods of geologic time.

The CliffsAP book is geared toward AP students, but most other sources have speciation as part of macroevolution. How do I approach this?

Answer 1

Definitions of terms, particularly terms which are frequently loosely used, are often problematic.

I think, as you say, that the distinction between micro- and macroevolution is an artificial one. They are fundamentally just degrees of the same process.

I would tend to agree more strongly with the Solomon definition than with the Cliffs one. Most of the things I've read, heard and used consider speciation events to be macroevolutionary rathar than microevolutionary changes.

Solomon makes the distinction between population and species because two separated populations of the same species will undergo their own independent microevolutionary changes because they are not necessarily sharing a common gene pool. While they have the potential to interbreed, the species as a whole may be separated into multiple populations which do not effectively interbreed with each other.

So, I would suggest just explaining this difference between sources as a largely sematinc issue, and indicate that many texts don't even attempt to distinguish microevolution from macroevolution.

Hope this helps...

Answer 2

Easy....

Micro-evolution is the process where Shaquille O'Neal and Billy Barty could both evolve from a single human. Minor, insignificant change within a specie.

Macro-evolution is the process where Mozart, Einstein and George Washington could evolve from a fish, a salamander and a caterpillar....

Major change, one specie to another....

Answer 3

Micro is like when Bacterias become resistant to drugs. Micro refers to minor change in an organism to make it better.

Macro evolution is changes within different species. For example chimpanzee to human.

Micro can occur in short amount of time, and we see it happening everyday in bacteria's virus's and unicellular organism. One of the properties of aids virus is that it evolves very quickly. Since it's a virus and only has RNA, the RNA has a very high mutation rate. usually in one person the aids virus has so many different versions of itself that its hard to give drugs that target all of them.

Macro evolution takes longer. That is the reason we can't observe it.