What is evolution?
Most non-scientists seem to be quite confused about precise definitions of biological evolution. Such confusion is due in large part to the inability of scientists to communicate effectively to the general public and also to confusion among scientists themselves about how to define such an important term. When discussing evolution it is important to distinguish between the existence of evolution and various theories about the mechanism of evolution. And when referring to the existence of evolution it is important to have a clear definition in mind. What exactly do biologists mean when they say that they have observed evolution or that humans and chimps have evolved from a common ancestor?
In its most common and familiar usage evolution is simply change over time. Thus technologies, political and economic systems, languages, even landscapes and galaxies are said to evolve or change over time. Biological evolution is an entirely different concept, and it applies to populations, not individual organisms. Biological evolution is the genetic changes in populations of living things through time that lead to differences among populations. This process has two important components: genetic continuity and change across generations. A simpler phrase for these two, the one employed by Charles Darwin and every bit as applicable today, is descent with modification (LaHaye, Noebel, 12).
Evolution deals with the science of life processes on the planet Earth. It does not include the origin of the universe (cosmology) or the formation of stars (astronomy) or planets (planetary science) or life itself (abiogenesis). Nor does it deal with the possibility of life after death (theology or philosophy). Evolution has two basic definitions:
- Descent with modification from common ancestors, resulting in diversification/speciation.
- Viewed from genetics, "a change in allele frequency within a population over time."
Is Evolution a Fact or.....
