Exploring Evolution

   My biggest breakthrough so far has been the realization that science does not have answers for everything but what makes it so fun, is working towards attempting to answer these questions. An example would be scientists working on formulating a standard way to quantify fitness to this day. Going back to the blog post I defined evolution, I would rephrase my claim that evolution depends (in all cases) on natural selection to occur. Natural selection may not lead to evolution. According to The Princeton Guide to Evolution, Losos claims,  Natural selection can occur without leading to evolution if differences among individuals are not genetically based. For natural selection to cause evolutionary change, trait variants must be transmitted from parent to offspring; if that is the case, then offspring will resemble their parents and the trait variants possessed by the parents that produce the most offspring will increase in frequency in the next generation.   What...

  I do think mutation rates evolve; the rate of mutation is central to evolution. Mutation rates have traditionally been thought of as the result of adaptability. As an organism becomes more adapted to its environment, its chances to adapt further are reduced significantly, a possible benefit of mutations. As an organism adapts to an unchanging environment, mutation in general becomes almost exclusively disadvantageous to the organism, and natural selection should then be expected to favor a decrease in mutation rate. According to the general reduction principle, where it is physiologically possible, the mutation rate would evolve to zero in an unchanging environment. On the other hand, in an environment that changes over time, there is endless room for improvement due to the continuous supply of potentially beneficial mutations. In a changing environment, therefore, it is easy to see how a certain amount of mutation might be beneficial even vital. An example is RNA viruses that re...

  When Charles Darwin articulated his theory of evolution by natural selection, he focused on adaptations – the changes that enable organisms to survive in new or changing environments. He claimed that selection for favorable adaptations allowed ancient ancestral forms to gradually diversify into many species. Natural selection is not questionable, but some scientists have argued that most evolutionary changes appear at the level of the genome and are essentially random and neutral. According to the Princeton Guide to Evolution, natural selection can occur without leading to evolution if differences among individuals are not genetically based. The neo-Darwinian theory of evolution argues that such a mode is possible only as neutral evolution. The neutral theory of molecular evolution contends that at the molecular level, most evolutionary changes and polymorphisms within species are not caused by natural selection, but by random genetic drift. The key input required by the neutral ...

   In a biological setting fitness simply refers to reproductive success and reflects how well an organism is adapted to its environment. It is a key concept rooted at the core of the theory of natural selection. There are several ways to measure fitness; for example, absolute fitness (w abs ) which measures the ratio of a given genotype before and after selection while, relative fitness (w) measures differential reproductive success which is, the proportion of the next generation’s gene pool that is inclined from a particular genotype compared with competing genotypes. Absolute fitness is calculated as the product of the proportion survival and the average reproductive rate. Relative fitness of each genotype is calculated by dividing each genotype’s survival and/reproductive rate by the highest survival and/or reproductive rate among the given genotypes. The overall survival rate is the percentage of individuals born that survive to reproductive age. Reproductive rate for any...

    Jean -Baptiste Lamarck was one of the first scientist to develop and present a rational, comprehensible explanation for the process of evolution however, Charles Darwin is credited as the mastermind behind the theory of evolution by natural selection. Charles Darwin’s theory of evolution greatly impacts our current understanding of change in heritable traits of biological populations over successive generations. Unlike Darwin, who argued that all extinction is selective, that species not able to compete with other species die out, Lamarck claimed that species did not die out in extinctions, instead they improved into other species. He believed that living organisms evolved in a continuously upward direction. Simple life forms were raised from dead matter, that eventually became complex life forms with humans being the closest to reaching perfection. An ongoing spontaneous generation was what Lamarck used to explain how simple life forms could live along side more complex l...

     Species change through time (microevolution), is one of the predictions Darwin’s idea of descent with modification makes that I find interesting. Darwin projected that microevolution would be a process of continuous and gradual change. Microevolution is a selection occurring on a single or few genes in a population over a short period of time. It is evolutionary change on a small scale for example, between one generation and the next generation, the frequency of a gene for pesticide resistance in a population of crop pests increases, through artificial selection. It is an alarming problem, but pests are only following the rules of evolution, the best-adapted survive. When a pesticide is first used, a small proportion of the pest population may survive exposure to the pesticide due to their distinct genetic makeup. These individuals pass along the genes of resistance to the next generation. Successive uses of the pesticide increase the proportion of less-susceptible i...

Evolution is the gradual change in characteristics of a species over generations that relies on the process of natural selection. Evolution is centered on the idea that all living organisms are somewhat related and progressively change over time. Based on the knowledge I acquired from Modern Genetics (BIOL 450), resemblances in both the physical structure and development of embryos are a communication of shared DNA, a direct outcome of common ancestry. The gradual change in the characteristics of a species relies on genetic variation. Genetic variation can be caused by mutations, random mating, random fertilization, and recombination of homologous chromosomes during meiosis. Changes in the characteristics can also be affected by climate, culture, and the lifestyle of organisms. Genetic variation then enables natural selection. Natural selection plays a huge role in driving the evolution of life. In natural selection, individuals with environmentally selected traits are better able to a...

  Hello there! My name is Tashongedzwa Mataswa, an international student, originally from Zimbabwe. I am a senior majoring in Human Health Biology. I plan to study podiatric medicine starting next fall. I am most passionate about myself. Self-improvement, and future development are very important to me. Time with family and engaging in volunteer work are some of the things I feel good about choosing to do, not just for others, but for myself as well. Evolution and biology provide a sensible context for one to examine themselves and the larger environment they are a part of physiologically, cognitively, socially, and emotionally. What fascinates me about evolution is the fact that we know so much about it then again, we know so little about it. Evolution can help one know through provided evidence what happened billions of years ago, but it is quite a challenge for one to know most of the bacteria that have lived in humans over time. My roommate's dog that has been bred to rescue he...