Student Evolution Blog

 Organisms can be classified by two reproductive types, asexual and sexual. Asexual reproduction produces genetically identical offspring to the single parent. However, sexual reproduction produces offspring from the combination of genes from two parents, resulting in each individual being genetically unique. There are numerous advantages to an organism sexually reproducing mainly stemming from increased genetic diversity within a species. Increasing genetic diversity allows a species to limit harmful mutations, select beneficial mutations, and reduce disease risk. There are three common terms associated with this concept. First, the red queen hypothesis states that organisms are constantly evolving and adapting to their environment to survive, resulting in no species gaining a constant advantage over another species. This is a benefit of sexual reproduction because the increased genetic diversity helps the species remain kept up with the adapting environment. Second, heterozygosit...

 

Species is such a difficult word to define because of the drastic variety of creatures on the planet. Since no universal definition exists, scholars have defined the term in four concepts. The biological concepts divide species by reproductive isolation. It states that a species is a group of individuals that can mate with each other and not with other species. This definition is only true for individuals with reproductive data, which excludes every asexual organism and extinct organisms whose reproductive data was not collected. The morphological concept groups individuals in a species by their body shape and other structural features. However, morphological characteristics can provide subjective division. For example, some people may view one physical characteristic as a dividing trait between species, but others may see the characteristic as unimportant. The ecological concept classifies species based on their interaction with the environment, i.e. food, adaptation, and survival ins...

 

 Phenotypic plasticity in an environment is the change in an organism caused by environmental stress. Some common changes in the organism include color, size, eating habits, physiology, and other behavioral or phenotypic traits that can be easily modified with their conditions. These changes lead to evolutionary processes because, if the changes are hereditary, they are passed onto their offspring and begin being selected for or against in a population.  For example, as the temperature changes to where it is warmer for longer in an environment, it becomes more beneficial to be a brown bunny compared to a white bunny because it is not snowing as often. The brown bunnies therefore have a higher survival rate. However, 100 years ago, only white bunnies were present in the population. One bunny mutated and became a creamy color of fur instead of pale white. This bunny found it easier to survive and 50 years later, more cream bunnies appeared! We were even starting to see bunnies b...

 Even though an organism's genotype is passed from generation to generation, its phenotype is selected for in nature. Genotypes, or the genetic makeup of an organism, encode for the phenotype, or the physical characteristics of an organism. This selection process is seen throughout populations because an organism's size, color, leg length, and many other physical characteristics help it survive and reproduce in an environment. The genes of these phenotypic traits that aid in an organism's survival are passed from generation to generation, resulting in the physical traits of an organism being selected for and increasing in frequency in a population over time.