Skittlefish Lab Report

Natural Selection is the concept that organisms better adapted to their environment tend to survive and produce more offspring. This leads to the creation of populations and diversity of life within them. In the Skittlefish Lab, many separate occurrences can be observed which detail and explain how Natural Selection works on a population over a period of time. Certain adaptations in a species in its entirety may display how individuals impact the whole population as they pass their traits onto their offspring, which do the same. This lab required students to observe the individual “Skittlefish” and “Sea M&Ms” in different environments as they camouflaged and hid from predators. In the end it was conclusively decided that evolution happened not to an individual but to a population as a whole, because an observable population is required to examine and record variation between species.

Students started off with a population of ten Skittlefish (skittles) on an orange reef (construction paper). The skittles had varying colors, and the adaptive trait being examined was the ability to blend in with the reef so the predators would not find them. The hypothesis that was thought up was that individuals’ survival was based on their location and coloring. The first year began with two of each color, and 5 Skittlefish were eaten that “year”. The ones eaten were two green, two purple, and one red. Then each Skittlefish had one offspring of the same color. By the end of five years, only the orange Skittlefish had survived and reproduced, and it was clear how the genetic diversity had lessened over the span of those five years. The graphs show that the orange Skittlefish would always be the least impacted by predators compared to the other colors, showing that the population in its entirety, not just the individual, was impacted by the environmental factor of