In 1859 Charles Darwin's The Origins of Species was introduced to the world Consequently the study of life and where it came from has not been the same since For more than 150 years Darwin's work has been evolving into a powerful and multi faceted theory and has become the foundation for many modern sciences The basis of the evolutionary theory is that living organisms can change over time and thus produce new species from this variation resulting in all species sharing a common ancestor that long ago made the decision to crawl out of the primordial soup When discussing evolution it should be stressed that individual organisms don't evolve genetically the population that an organism belongs to can evolve as each generation contributes different traits to the proverbial pool The process of evolution can be explained through Darwin's three principles of evolution and the four processes of evolution Add to this the material evidence of evolution and one has reason enough to believe the theory fossil records clearly show that the process of evolution is no longer merely a philosophy The first of Darwin's three principles of evolution is variability meaning that no two individuals are identical in all respects Lavenda and Schultz 40
Variability plays a significant role in evolution it directly affects a species ability to adapt and survive in a changing environment Genetic variability means that there is a potential for a genotype to change when exposed to environmental or genetic factors thus giving the organism's offspring's population an advantage when facing that factor in the future Inheritability is the second of Darwin's three principles of evolution Essentially evolution occurs when inheritable traits become more common or rare in a population this can happen randomly through mutations or genetic drift or non randomly through natural selection but the genes transferred between populations and generations must be inheritable The third of Darwin's principles and the first of the four processes of evolution is that of natural selection Evolution by differential reproductive success natural selection is a two step process first random genetic information must be produced Second the specific traits of an organism that are desirable in other words better suited to equip them to meet the environmental challenges that they face and thus are more able and likely to survive are passed onto their offspring and the cycle begins again As explained by Lavenda and Schultz and according to Darwinian principles pandas got their thumbs 40 due to those with longer wrist bones than others prevailing in the competition for bamboo to eat These elongated wrist bones made the process of gathering bamboo to eat far more efficient meaning that the pandas with said elongated wrist bones survived and had more offspring than those with shorter wrist bones This lead Darwin to conclude that the varietals must have descended from a distant common ancestor
The second process of evolution is mutation Mutations occur when the form of a gene changes randomly This unpredictability is a divergence from the normal practice of stable gene inheritance as they are not goal oriented Mutations can be beneficial like pesticide resistance in insects or harmful like cystic fibrosis in humans The third process of evolution is genetic drift which is an umbrella term encapsulating the founder effect and the bottleneck effect The founder effect is the loss of genetic variation that occurs when a new population is established out of a larger population by a small number of individuals An example of the founder's effect in humans can be found in the Amish having higher than normal rates of polydactyly extra fingers due to the Amish community being founded by a relatively small group with higher than normal polydactyl rates Because the Amish usually do not reproduce outside of their community the skewed allele frequency is maintained throughout generations The bottleneck effect is the potential loss of alleles after an event such as disease or disaster greatly reduces the size of a population The fourth process of evolution is Gene flow the introduction of new genetic information This transfer of alleles between populations can be one way like a bee delivering pollen from a neighboring field to another species of flower or two way like two separate herds of deer interbreeding Gene flow is essential in the process of evolution as it maintains variation within a population yet reduces variation between populations on a larger scale As Steven Stanley and evolutionary biologist states the theory of evolution is not just getting older it is getting better 32 When Darwin published The Origin of Species the notion that all life on earth being descended from a common ancestor was fiercely debated among the scientists of that day Today there is no substantial scientific doubt about the many close evolutionary links found between all organisms on earth Evolution is one of the most vital concepts in current science and supports and is supported by many different fields of scientific study
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