Evolutionary theory is based on several assumptions. What are these assumptions and are they valid?

These sites will help you with this assignment.

http://en.wikipedia.org/wiki/History_of_evolutionary_thought

http://en.wikipedia.org/wiki/Evolution_as_theory_and_fact

http://www.allaboutscience.org/evolution-of-man.htm

http://anthro.palomar.edu/evolve/evolve_3.htm

http://www.religioustolerance.org/ev_proof.htm

Evolutionary theory is a scientific explanation for how species have changed and diversified over time. It is based on several key assumptions, which are generally considered to be valid within the scientific community. These assumptions are as follows:

1. Variation: The first assumption is that there is variation among individuals within a population. This means that there are differences in traits, such as size or color, among members of the same species. This variation can be due to genetic factors or environmental influences.

2. Heredity: The second assumption is that these variations can be inherited from one generation to the next. This means that offspring generally resemble their parents to some degree. Genetic information is passed on through mechanisms such as DNA replication and sexual reproduction.

3. Overproduction: The third assumption is that more offspring are produced within a population than can survive to reproduce. This leads to competition for resources, such as food or mates, among individuals. Only a fraction of the offspring will survive long enough to reproduce themselves.

4. Differential Reproduction: The fourth assumption is that individuals with certain variations are more likely to survive and reproduce than others. This is referred to as "fitness". The variations that increase an individual's chances of survival and successful reproduction are more likely to be passed on to the next generation.

5. Natural Selection: The fifth assumption is that these variations and the differential reproductive success of individuals lead to a gradual change in the population over time. Those variations that confer advantages in the given environment tend to accumulate, while disadvantageous traits are less likely to be passed on. This process is known as natural selection.

These assumptions have been supported by extensive research across various scientific disciplines, including genetics, paleontology, and ecology. However, it is worth noting that scientific theories are always subject to further examination and refinement based on new evidence.

Evolutionary theory is a widely accepted scientific understanding of how life on Earth has changed and developed over time. This theory is supported by a range of evidence from various scientific disciplines. While there are several key assumptions underlying evolutionary theory, it is important to note that these assumptions are generally considered valid based on the available evidence. Let's discuss the main assumptions of evolutionary theory and their validity:

1. Common Descent: This assumption suggests that all species share a common ancestor. In other words, all living organisms on Earth are connected through a branching tree of life. This concept is supported by numerous lines of evidence, including the similarities in genetic code, anatomical structures, and fossils found across different species. The validity of this assumption is strongly supported by the wealth of comparative data from various fields of study.

2. Gradualism: This assumption holds that evolutionary change occurs gradually and incrementally over long periods of time. This means that species evolve through small, cumulative changes in their traits over successive generations. The validity of gradualism is supported by the observation of transitional forms in the fossil record, as well as the understanding of how genetic mutations and natural selection can lead to gradual changes in species' characteristics.

3. Natural Selection: This assumption proposes that there is a continuous struggle for survival among individuals within a population, and those with traits that provide a reproductive advantage are more likely to survive and pass on their genes to future generations. Natural selection is supported by extensive evidence from fields such as genetics, biogeography, and ecology. This assumption has been repeatedly tested and validated through experiments, observations, and the study of diverse organisms in various environments.

4. Genetic Variation: This assumption states that there is heritable variation within populations, meaning that individuals within a species display differences in traits that are passed down through generations. Genetic variation is a well-established concept verified through extensive genetic research. It is supported by our understanding of genetic mechanisms like gene mutations, recombination, and gene flow, which lead to diversity within populations and subsequent evolution.

Overall, these assumptions of evolutionary theory are considered valid due to the breadth and consistency of evidence from multiple scientific disciplines. However, it's important to note that scientific theories are never considered absolute truths but are provisional explanations based on the current evidence. As new evidence emerges, these assumptions may be refined or modified, as is the nature of scientific progress.