Home Forums Hunting & Shooting Hunter's Campfire Scientists Observe Evolution in Twenty Year Experiment

Evolution works in many ways, not just natural selection. Evolution is simply a change in the gene frequency in a population over time. It can be small changes or big changes. A new species does not have to arise for evolution to have occurred. ( The concept of species is an artificial human concept that has very little basis in reality if you look at it very closely. The only really accurate definition of species is that it is whatever an eminent taxonomist says it is.) It can occur quickly or it can occur slowly. It can be caused by new mutations, natural selection, genetic drift, immigration, emigration, and a few other factors. It does not always lead to better adaptation to the environment but usually does. It can be quite random (genetic drift) or quite nonrandom (natural selection). Natural selection acts on the individual but the effects are realized in the population. Individuals do not evolve, populations do. An individual cannot evolve into something else. The term fitness is greatly misused and misunderstood. Animal A is more fit than animal B if animal A has more reproductively successful offspring than does animal B. That does not mean more children, but rather more children who also have children. Natural selection does not choose the best possible solution to a problem but rather the best available solution. It is a passive process that can not actively design a new gizmo but rather must try to maximize fitness with the gizmos that are already available or that are made available by new mutations or immigration. There are several assumptions Darwin used to explain his concept of natural selection.

1. Organisms produce more offspring than survive to reproduce.

2. Which individuals survive to reproduce depends somewhat on genetically based traits possessed by the individuals.

3. Those that do survive to reproduce will pass on some of those genetically based traits to their offspring.

4. Over time the population will retain more of the successful traits than of the unsuccessful traits.

There will be, therefore, a change in the genetic makeup of a population. That is what evolution is.

Genetic drift, unlike natural selection, can be quite random. A portion of the population may be eliminated by some factor that has nothing to do with the genetic makeup of individuals in the population or the population can get so small (population bottleneck) that only a small amount of the genetic variation of the population remains. (Just think what the human population of the future would be like if a bomb wiped out everybody except the seven castaways on Gilligan's Island.)

Immigration or emigration can change the genetic makeup of a population. That is also evolution. We humans here in the USA are experiencing that right now with the massive immigration we are experiencing from other populations. The genetic makeup of our population is changing very rapidly because of this. Refugees take their genes with them and change the genetic makeup of the population they left ans well as the population they entered.

Basically, evolution is a quite complex subject. It does not have one cause or one effect. It has its own set of terms that must be understood if discussions are to be worthwhile. It is, indeed, an interesting topic.