MOLECULAR BIOLOGY

Recently, molecular biology has yielded a wealth of information
on evolutionary relationships. Just as animals can have homologous
structures, animals may also have homologous biochemical
processes.
Ultimately, structure and function are based on the genetic
blueprint found in all living animals: the DNA molecule.

Related animals have similar DNA derived from their common
ancestor. Because DNA carries the codes for proteins that make
up each animal, related animals have similar proteins. With the
modern laboratory technologies now available, zoologists can
extract and analyze the structure of proteins from animal tissue,
and compare the DNA of different animals. By looking for dissimilarities
in the structure of related proteins and DNA, and by
assuming relatively constant mutation rates, molecular biologists
can estimate the elapsed time since divergence from a common
ancestral molecule.
Biogeography, paleontology, comparative anatomy, and
molecular biology have all generated impressive documentation
of evolution since the initial studies of Darwin. The vast majority
of scientists have no doubt as to the reality of evolution. Evolutionary
theory has influenced biology like no other single theory.
It has impressed scientists with the fundamental unity of all
of biology.