DessBlog

 What is a species is a complicated question. There is not a single answer, but rather many ways to define it; here are a few.  1. Biological species concept 2. Morphological species concept 3.  Ecological species concept  4. Phylogenetic species concept  Tj

Genetic drift is the reduction of genetic variation due to random chance. In the comic strip below, I tried to demonstrate genetic drift, specifically the founder effect, by showing how, by random chance, three random spiders are blown away by a tornado and land on an island, then reducing genetic variation and fixating on the SZ allele. An example that would not be genetic drift would be if the original generation of spiders were to all turn red due to predators which would then be natural selection.

 Plasticity can be defined as an organism's ability to adjust a trait in response to an environmental change. How one would identify if a trait they are studying is plastic would be by designing a controlled experiment to see if the trait changes in different replicated environments. In the comic strip below I drew out an example of what plasticity is, in a simpler manner. You can see how the trait of the frog (color), changes when something in its environment changes, which in this case is the type of grass. 

Selection acting on the phenotype produces evolutionary change because the phenotype which is an expressed trait such as the color, or size of an organism can influence the survival rate or death rate of an individual, therefore influencing the genotype that will be passed on to the next generation. So over time, this process changes the genetic makeup of a population.

 First, let's define what absolute fitness and relative fitness are. Relative fitness can be defined as a comparison of reproductive success between members of the same population. Absolute fitness is the total number of offspring an individual produces, that survive, successfully having passed on their genes. In the drawing below we can see how the absolute fitness of an individual differs from the relative fitness of the population. The last drawing shows how our population of goats goes through positive selection.

"Survival of the good enough" is a more accurate description of natural selection because it acknowledges that an individual does not have to be the best or have the best traits to survive and reproduce, but are good enough to survive and reproduce due to adaption to their environment. Unlike the phrase "survival of the fittest" which can be  misinterpreted as, an organism that has the "best traits" will survive and reproduce more, when in fact that is not the case.  Individuals fitness in comparison to other individuals of the population