NATURAL SELECTION IS ‘NOT DEAD YET’ INTRO Natural selection is a process that affects the relative proportions of a biological, heritable trait within a population of individuals as a result of differential mating success. Humans, like all other organisms on the planet, are subject to natural selection, and have been since the birth of our species 200,000 years ago. However, a dramatic change in the pattern of human adaptation to selective pressures occurred around 12,000 years ago when humans began to aggregate in larger numbers, sustained by the innovation of agriculture. This period, known as the Neolithic demographic transition, marks the beginning of contemporary human society (Armelagos and Dewey, 1970; Karlsson et al., 2014). The statement ‘in contemporary human societies, natural selection is not a driver for genetic evolution’ does not well describe the complexities of human adaptation; while popular opinion suggests that advances in technology have separated humans from natural forces, in fact as long as there is variance in fitness which co-varies with phenotypic traits, humans will not be exempt from natural selection (Courtiol et al., 2012; Milot and Pelletier, 2013). While human societies from the beginnings of agriculture, cities, and rapid population expansion respond with ever increasing technological solutions to environmental pressures, evidence of natural selection can still be found by looking for observable, heritable traits that confer a fitness advantage to the individual that has that trait. Some of the most dramatic examples of natural selection affecting human populations within the last 12, 000 years have resulted from human adaptation to infectious disease. Several examples of natural selection acting ... ... middle of paper ... ...ubonic plague. Natural selection in contemporary human societies is not dead yet, contrary to popular opinion. Morbidity and mortality are still a function of illness, environment, and culture across the globe. Even faint signals of natural selection can be detected with these new advances in genetic sequencing, and when a signal provides the link between a survival or reproductive advantage, a phenotypic, observable trait, and a heritable gene, it proves that natural selection is present. Despite our many technological advances as a species since 12,000 years ago when we began to significantly impact our own ecology significantly, we do not yet have a cure to death, disease, and discrimination. The complicated interaction between genes, environment, and culture will continue to affect human evolution, even if it is in ever changing, increasingly complicated ways.
I learned that the gene for telomerase is the focus for a discussion of aging and immortality. I also learned that the ethnic differences in the frequency of a particular breast cancer gene are used to describe the relationships among population genetics, prehistoric migrations, and linguistic groups. Also, the gene for the classical ABO blood group is the springboard for a discussion of genetic selection and drift. This book reveals genes that we share with all living creatures and those that are unique to our species. It describes genes that are essential to every cell and then those that seem to serve no useful purpose at all. It tells us about genes that predict disease with complete certainty and those that only tilt the scales.
Others include defenses, genes, and design compromises. Some health practitioners treat symptoms without consideration of evolution. This is dangerous both to the individual and to society as a whole. If a fever is viewed as a highly evolved bodily defense, then the decision to treat that fever takes on a new level of consideration. If iron deficiency is a defense to chronic infection, should a supplement be prescribed? If the defense threatens the well being of the patient, then treatment is necessary. If the defense presents discomfort, but is fighting the pathogen, treatment may present the greater danger. On a societal scale, failure to consider evolution combined with over prescription of antibiotics to treat bodily defenses has lead to “superbugs” resistant to
Natural selection is associated with the phrase “survival of the fittest.” This basically means that the fittest individuals can not only survive, but are also able to leave the most offspring. The selection of phenotypes affects the genotypes. For example, if tall pea plants are favored in the environment, then the tall pea plants would leave more offspring behind, meaning that the offspring will carry tall alleles. Phenotypes that are successful have the best adaptations (characteristics that help an individual to survive and reproduce) to their environment. These adaptation arise from the interactions with living and nonliving aspects of the environment. Some nonliving aspects of the environment are climate, water availability, and concentration of mineral sin the
I have decided to write about four conditions, three of which are detailed in “Survival of the Sickest”, a book written by Dr. Sharon Moalem about how genetic diseases may have evolved to help the human race survive in the past. The diseases which I chose are Hemochromatosis, Diabetes, Transposons, and Sickle cell anemia. I decided to write about hemochromatosis because of how it affects the body by overloading the body with iron, how it evolved in Vikings to minimize iron deficiencies, and how it spread across the population as the Vikings began inbreeding as they colonized Europe. I chose to write about diabetes because of how it may have evolved to prevent blood from freezing during the Last Ice Age, and because of the impact which it has on society. I wrote about transposons, despite the fact that these are not diseases, because of the role they play in the development of cancer, the way they are used in cancer research, and the way they have affected the evolution of life. Lastly, I decided to write about sickle cell anemia because of its interesting relationship with a disease which continues to run rampant in Africa.
We are who we are because of a biological process called natural selection. The theory of biological evolution by natural selection first exposed by Charles Darwin (1859) is probably the most revolutionary idea in the history of human thought. Surprisingly, despite the crucial importance for the understanding of ourselves as a species and other biological species, few men actually understand or even know, the natural mechanism that created us. Never a seemingly simple concept was so difficult to understand. It 's like natural selection, creating an intelligent species like ours, while hiding the elemental biological rationale behind its operation. But I suspect that the ultimate reason that natural selection is not part
Suzuki, David and Peter Knudtson. Genethics: The Clash Between the New Genetics and Human Values. Harvard University Press; Cambridge, Mass; 1989.
It was not that long ago that there was an age of no internet or computers. Life around the world has changed dramatically in the past thirty years. Technology has advanced at faster rate than ever before. We now know about many new things including humans including our DNA. It seems as though, the more we learn about the make up of our bodies, the more we are learning how to manipulate them. Do we want to let science take over our natural way of life? Russell Powell of the Journal of Medicine & Philosophy agrees that there is a common worry that humans could be harmed by genetic engineering of humans. The problem, Powell says, could potentially lead to the extinction of human life. By reducing human genetic diversity, we could end up with a biological monoculture that may increase our susceptibility to deadly diseases.
Charles Darwin’s theory of natural selection explains the general laws by which any given species transforms into other varieties and species. Darwin extends the application of his theory to the entire hierarchy of classification and states that all forms of life have descended from one incredibly remote ancestor. The process of natural selection entails the divergence of character of specific varieties and the subsequent classification of once-related living forms as distinct entities on one or many levels of classification. The process occurs as a species varies slightly over the course of numerous generations. Through inheritance, natural selection preserves each variation that proves advantageous to that species in its present circumstances of living, which include its interaction with closely related species in the “struggle for existence” (Darwin 62).
We live in a world where the strongest and most adapted survive which is called natural selection, which is also vital to my next argument on why I disagree with
If you were told to believe a side of an argument that did not have majority of evidence points on its side, would you? The theories of evolution, creation and intelligent design have been a debated controversy for years and years. These three theories have three different ideas. The theory that creationists have is to believe that concept and design require a Creator. Creationists usually tend to believe that each organism is created as a single and distinct organism. Evolutionists tend to believe that all life started from single celled organisms. They believe that these single celled organisms are part of a continuing evolution over a very long period of time and that this evolution results in the development of new varieties and different species. People who believe in intelligent design believe in the theory that the universe cannot have arisen by chance and was designed and created by some intelligent entity. Evolution is the theory that is most probable because of the fossil record, similarities in all organisms and genetic changes in a population over time.
In order for a species to survive, its population has to evolve. Evolution is the process of gradual change driven by natural selection to improve survival. Evolution is the explanation of how life got to its current state. Before the idea of evolution, the Bible gave the explanation of how things came to be, the Theory of Creation. Charles Darwin is credited for developing the theory of evolution. Scientist such as Georges Cuiver, James Hutton and Charles Lyell, and Jean-Baptiste Lamarck heavily influenced Darwin. It is because of Darwin’s voyage aboard the Beagle that we now have a scientific explanation of how species came to be. Canines have evolved and have been domesticated by artificial selection into our household pets. Unlike natural
Many scientists in the past, such as Aristotle and Plato, believed that there were no changes in populations; however, other scientists, such as Darwin and Wallace, arose and argued that species inherit heritable traits from common ancestors and environmental forces drives out certain heritable traits that makes the species better suited to survive or be more “fit” for that environment. Therefore, species do change over a period of time and they were able to support their theory by showing that evolution does occur. There were four basic mechanisms of evolution in their theory: mutation, migration, genetic drift, and natural selection. Natural selection is the gradual process by which heritable traits that makes it more likely for an organism to survive and successfully reproduce increases, whereas there is a decline in those who do have those beneficial heritable traits (Natural Selection). For example, there is a decrease in rain which causes a drought in the finches’ environment. The seeds in the finches’ environment would not be soft enough for the smaller and weaker beak finches to break; therefore, they cannot compete with the larger and stronger beak finches for food. The larger and stronger beak finches has a heritable trait that helps them survive and reproduce better than others for that particular environment which makes them categorized under natural selection (Freeman, 2002).
The science of paleoanthropology, which also tries to create a narrative about how humans came to be, is deeply technical. Paleoantropology is the science of the evolution of humans, and it is the base of all research in that field. Humans have undergone many different changes during the last hundred million years, and it is the paleoanthropologist's job to identify and explain these changes. In this research paper I will examine: human physical traits that define their species, human origins from pre-humans to modern humans, major discoveries and the history of human evolution, and what the future may hold as far as evolution for the human species.
For instance, our social environment is believed to promote or decrease the prevalence of specific diseases and other health-related issues. This promotion or de-promotion can be controlled and triggered by many social aspects. In this article, this concept is discussed by the authors regarding an aspect of our physical health that many individuals perceive as concrete: genes. The authors state “Research indicates that even in the case of single gene disorders, the severity and timing of genetic expression are affected by environmental triggers, and that established genetic risks can be exacerbated or become protective in the presence of specific environmental exposures” (Williams and Sternthal 4). This statement by the authors ultimately showcases the fact that genetic factors, an aspect of physical health believed to be absolute, can be affected by the different social triggers. Through the social environment, genes can ultimately be altered for the promotion or de-promotion of many diseases and health related issues. Thus, I believe that this quote is essential and important for discussion because it showcases many of the reasons why health inequities are in our society. Although genes are said to be concrete and hinder many diseases and health issues, these genes for which an individual is encoding something
Natural selection is based on the concept “survival of the fittest” where the most favourable individual best suited in the environment survive and pass on their genes for the next generation. Those individual who are less suited to the environment will die.