Evolution Class Experience

Can selection occur without natural selection? Background Genetic Drift is a change in allele frequency in a population due to random selection of genes. Mutations in the DNA can have no effect on the fitness of an organism. This means that even if evolution has occurred natural selection would not. These genetic changes can increase or decrease among the population. When an allele does not change the frequency in a population then genetic drift is acting on the allele. Allele frequencies tend to stay relatively stable in large populations because the gene does not affect fitness. However, in small populations fluctuation can occur leading to evolution - some alleles will become fixed and while others will disappear.  Genetic Drift in COVID-19  The genome of coronavirus is prone to mutations that can lead to genetic drift. It is crucial for vaccine developers to consider the sub-strains mutations. By using epitope information in spike protein (S), nucleocapsid protein (N), and...

     Natural Selection is a process of sorting by the reproductive success that occurs in populations of replicating units. Where units can be defined as molecules, cells, organisms, or larger units.  There are four conditions for natural selection to occur: (1) the units expressing the trait must vary in their reproductive success; (2) the trait must vary among the units in the population; (3) the correlation between the trait and reproductive success must be nonzero (i.e. positive correlation with reproductive success will yield an increase in frequency and vice versa); and lastly (4) the trait must be heritable.       Fitness is a measure of relative reproductive performance that can be used to predict long-term dynamics. In other words, fitness is an organism's ability to survive and reproduce to contribute genetically to the next generation. Heritable traits that have greater fitness will increase in a population subject to natural selectio...

Lamarck realized that life was not fixed due to his fascination with the fossil record. Lamarck argued that when environments changed, organisms had to change their behavior to survive. This is true as organisms tend to evolve due to environmental changes and other factors. However, in the mechanism in while organisms evolved he was incorrect. He believed that evolutionary change seemed from use and disuse.  Lamarck suggested that if a giraffe stretched its neck for leaves, the nervous fluid would flow into its neck and make it longer and this ability to have longer necks will be passed down through generations.  [1] Compared to Lamarck's theory of acquired variation, Darwin proposed the idea of inherited variation. Some giraffes would evolve to have longer necks, not by their neck fluid but through microevolution. These individuals would have an evolutionary advantage because they could feed on taller trees allowing them to have higher fitness thus yielding more giraffes with...

Darwin made two very important discoveries. First, descent with modification which is the pattern of evolution. Descent with modification makes five important predictions; (1) species change through time, (2) lineages split and diverge, (3) novel forms derive from earlier forms, (4) species are connected by descent from common ancestors - they are not independent, and finally (5) both the earth and life are old. The first three predictions are microevolution, speciation, and macroevolution respectively. Darwin had believed that evolution was rather slow, however, we now know that evolution actually occurs rapidly.  Microorganisms such as bacteria and viruses undergo rapid evolution. We are in the middle of a pandemic caused by the novel coronavirus known as SARS-CoV-2 since late 2019. The coronaviruses are named for their crown-like spikes on their surface. Coronaviruses that infect animals can evolve to new human coronaviruses. SARS-CoV-3 happens to be one that evolved from an ani...

I define evolution as small changes in our genotype that become our phenotype. This can be influenced by natural or unintentional phenomena. A natural phenomenon is the evolution of dark skin. Where people in the tropics developed dark skin to block out the sun for protection. While people away from the equator had lighter skin to absorb the sun and get good amounts of vitamin D during the winter. An unintentional phenomenon is the shrinking of the mouth and jaw. Recently, I heard in a podcast by the School of Greatness, James Nestor, a scientific journalist come on the show to talk about the truth about breathing. They touched on why our jaws are getting smaller, this is because dentists have been removing our teeth for years so much that evolution adapted to this intervention.  When I first learned about evolution, I was shocked to be quite honest. I understood why evolution and Christianity would contradict each other. However, I really believed the theory of evolution. Fast for...