which theory says that populations change slowly over time?
Evolution is a scientific theory used by biologists. It explains how living things change over a long time, and how they have come to be the way they are. Earth is very old. By studying the layers of rock that make up Earth's crust, we can find out about its past. This kind of research is called historical geology.
3. Population-Genetic Models of Evolution. Population geneticists usually define ‘evolution’ as any change in a population's genetic composition over time. The four factors that can bring about such a change are: natural selection, mutation, random genetic drift, and migration into or out of the population.. Population-Genetic Models of Evolution. Population geneticists usually define ‘evolution’ as any change in a population's genetic composition over time. The four factors that can bring about such a change are: natural selection, mutation, random genetic drift, and migration into or out of the population.