evolution perpetuates 4.5billion yo earth myth, page-203

wangjanglang ,

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?
One of the most respected evolutionary biologists has defined biological evolution as follows:

"In the broadest sense, evolution is merely change, and so is all-pervasive; galaxies, languages, and political systems all evolve. Biological evolution ... is change in the properties of populations of organisms that transcend the lifetime of a single individual. The ontogeny of an individual is not considered evolution; individual organisms do not evolve. The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next. Biological evolution may be slight or substantial; it embraces everything from slight changes in the proportion of different alleles within a population (such as those determining blood types) to the successive alterations that led from the earliest protoorganism to snails, bees, giraffes, and dandelions."- Douglas J. Futuyma in Evolutionary Biology, Sinauer Associates 1986

It is important to note that biological evolution refers to populations and not to individuals and that the changes must be passed on to the next generation. In practice this means that, Evolution is a process that results in heritable changes in a population spread over many generations.

This is a good working scientific definition of evolution; one that can be used to distinguish between evolution and similar changes that are not evolution. Another common short definition of evolution can be found in many textbooks:

"In fact, evolution can be precisely defined as any change in the frequency of alleles within a gene pool from one generation to the next."
- Helena Curtis and N. Sue Barnes, Biology, 5th ed. 1989 Worth Publishers, p.974