Evolutionary Biology Charles Darwin

Charles Darwin is accredited with the title Father of Evolution’, appropriately placed due to his proposed theory on the Origin of Species

and the definition of evolution as a gradual process giving rise to new organisms. He proposed the classical natural theory of evolution. In the natural selection theory, evolution is defined within the limits of selection pressure giving rise to individuals that are fit to survive (http://www. Palomar.edu.com). Nature provides the opportunity for organism to adapt, this new adaptations give rise to new organisms capable of overcoming challenges like hunting for food or exploring new food sources. Ideally natural selection gives organism with the competitive edge to reproduce and survive the upper hand (http://www.scientificamerican.com).

Hence what evidence do we have that evolution exist?Four key sources can be used as evidence for evolution;

1) The discovery of fossils that record change in earlier species

2) The similarities in related life forms in regard to chemical and anatomical features

3) The geographic distribution of related species

4) The recorded genetic changes in living organisms over many generations

Fossils that record change in earlier species

The British museum holds a valuable transitional specimen known as the link between birds and reptiles, a fossil record demonstrating the missing link and the gradual process of evolution. The Archaeopteryx lithographicawas discovered after the publication by Charles Darwin, Origin of species

(Gawne, 2015). The discovery of this fossil record was key evidence in the support of Darwin theory. However, he was reluctant and slow to embrace it most likely due to his beliefs on the classifications of specimen. Nevertheless, with time fossils records and the field of Palaeontology has provided evidence for evolution over a period of time. Fossils records from sedimentary rocks have been shown to demonstrate the chronological existence of organisms such that more primitive version are found in layers of rocks dating billions of years ago (NAS, 2016).

Chemical and anatomical similarities between life forms

Common anatomical features can be used to compare different organisms, and the common these features are, the closer they could be coming from one descendant. The picture (National Academy of Sciences) demonstratesa bat wing, mouse forelimb and a human arm with one similarities; a common four limb descendant. Even though the function of the limb is different, it is just a modification to support the adaptation of the organism in its environment. A bat flies, the mouse runs and the human arm writes.

Geographic distribution of related species

The distribution of species in certain geographic location have widened our understanding and provided evidence for evolution. Island biogeography has been used to explain species richness which is the count of species found in an Island. The colonisation of Island by species is affected by how far it is from the main land. The extinction of species from an Island is also affected by its size so that the smaller it is the process of extinction of species in it will be high. How is this evidence for evolution? Separation of species originating from one descendant can be studied by their presence in certain geographical areas. For example approximately 3 million years ago mammalian populations found in North and South Americawas different until the emergence of Isthmus of Panama occurred. The event resulted in South Americanoriginated mammals like Armadillos been found in the North and North American species like the mountain lion been found in the South (NAS, 2016).

Genetic changes in living organism over generations

            The Deoxyribonucleic Acid (DNA) is the genetic code useful in delivering the message on how our physical or phenotypic appearance and biochemical capacity to manoeuvre in our environment occurs. The neoDarwinian evolution theory emphasizes on the role of genetic mutation on evolution of species (Skinner, 2015).For example mutation in a group of bacteria exposed to an antibiotic in the lab will give rise to two groups of bacteria; the susceptible and resistance colony. The resistance bacteria have selectively propagated the resistance gene that evolved to establish a new population of bacteria. Another example is the evolution of the malaria parasite Plasmodium species. In a study by Loy et al., 2016 comparative genomics was used to compare the species of Plasmodium found in apes and humans. Plasmodium praefalciparum

based on nuclear and mitochondrion analysis commonly found to be infecting Gorillas in West Africa, has a role in the origin of the human malaria parasite Plasmodium falciparum.

Conclusion

A unified theory of evolution that includes not only the natural selection proposed by Charles Darwin might help our understanding of evolution. This means embracing the role that the environment and genetic play in evolution of species. Continued evidence by palaeontologist, evolutionary biologists, and anthropologist is needed as we redefine the importance of evolution in modern world.

References

Dorothy E. Loy, Weimin Liu, Yingying Li, Gerald H. Learn, Lindsey J.

Plenderleith, Sesh A. Sundararaman, Paul M. Sharp, Beatrice H. HahnOut of

Africa: origins and evolution of the human malaria parasites Plasmodium

falciparumand Plasmodium vivax

International Journal for Parasitology.

Michael K SkinnerEnvironmental Epigenetics and a Unified Theory of the

 Molecular Aspects of Evolution: A Neo-Lamarckian Concept that

Facilitates Neo-Darwinian Evolution Genome Biology and Evolution,

Volume 7, Issue 5, 1 May 2015, Pages 1296–1302,

https://doi.org/10.1093/gbe/evv073.

National Academy of Sciences(2016) Science and Creationism: A View from the

 National Academy of Sciences: Second Edition. Washington (DC): National

 Academies Press (US); 2016. Evidence Supporting Biological Evolution

Available from: https://www.ncbi.nlm.nih.gov/books/NBK230201/

Evidence for Evolution https://www2.palomar.edu/anthro/evolve/evolve_3.html

            Accessed on 15/11/2018.

Richard Gawne (2015)Fossil evidence in the Origin of SpeciesBioScience65:

            1077–1083doi:10.1093/biosci/biv124.

Science Daily Picture of Panama before formation of Isthmus

            https://www.sciencedaily.comAccessed on 14/11/2018

ScientificAmerican