Group 3: Lisa Williams, Kayla Hart, Camilla Zambrano, Kaydence Alexis, Riham Islam

Professor Zayas

ENGL 21003: Writing for the Sciences

Tuesday, February 22, 2022
Natural Selection

Introduction
In this lab, we will study the scientific theory of evolution by identifying and describing
the role of genetic variation and environmental influences in natural selection and biodiversity. Predators will act as selective agents for their prey, members of which come in a variety of colors. Most species would not have thrived if not for natural selection. Natural selection demonstrates how successful qualities are handed down through reproduction while poor features are eliminated and are not passed down. This leads to adaptive species, which means that a trait is frequent in a population because of its improved activities. The population of an organism will be affected by its traits, which will increase or decrease depending on the number of predators available to that organism. As a result, animals will begin to adapt in new ways in order to increase their chances of survival. Darwin’s theory of evolution, natural selection plays a crucial role in species survival. The variation of each generation of individual species has a different combination of variable traits, resulting in evolutionary change. Darwin’s most famous term was “survival of the fittest.” To survive, species adapt and change according to their needs and environment. The strong and adaptable will survive, and the weak will die. The goal of this experiment was to see if a particular characteristic would improve or decrease the survival rate in a population, resulting in species adaptation. The hypothesis is that there will be a greater favorability of traits of each new generation of rabbits as their environment changes. To be more specific, wolves being introduced to the environment will increase the frequency of darker color fur in the rabbit population. Additionally, introducing tough food to the environment will increase the frequency of longer teeth amongst the rabbit population.

Methods & Materials
Using the virtual lab simulation provided by the University of Colorado Boulder, we
For the control group, the first rabbit had white fur and short teeth, which are both
were able to control the mutated traits and if those traits were dominant or recessive. Since the hypothesis was the effect of environmental factors on the frequency of mutated traits, three trials of the simulation were run. One, creating a baseline for our data with no environmental factors, two introducing wolves into the environment, and three introducing tough food into the environment. To ensure that the experiment is designed to only compare the effects of wolves and tough food on the rabbit population, some controls of the experiments were that each trial was under sunny conditions, the first rabbit always had white fur and short teeth, and the population was observed for 15 generations. For the control group, the first rabbit had white fur and short teeth, which are both dominant traits. The simulation was run for 15 generations and the proportion of traits and the total population of rabbits were recorded. For the first experimental group, wolves being the environmental factor, the first rabbit had white fur and short teeth. Additionally, white fur was set as dominant and brown fur as recessive. The simulation was run under these conditions for five generations and then wolves were introduced. From generation 5 to generation 15, the proportion and frequency of traits among the rabbit population were recorded. This procedure was repeated for the second experimental group, tough food being the environmental factor, however, shorter teeth were set as dominant and longer teeth as recessive. Finally, the frequency of traits and the total population were recorded.

Results:

Control Group

For the control group observed, white fur was selected as well as short teeth for the bunnies. There were no environmental factors in the population in this group. According to the diagram, there was no change in the frequencies and proportions of the genes. White fur and short teeth remained 100% present as the generations increased.

Environmental Factor: Wolves

This population started off with 100% white fur. This remained a dominant gene as the generations increased and no environmental factors were introduced. In generation 5, wolves were introduced into the environment. Brown fur became more present within the population. At generation 10, only 54% of bunnies had white fur and by the end of that generation, it decreased to 20%. At around generation 12, 100% of bunnies had brown fur. The number of bunnies alive at the end of the generation increased as white fur decreased in the population.

This population started off with 100% short teeth. This remained a dominant gene as the generations increased and no environmental factors were introduced. In generation 5, tough food was introduced into the environment. Longer teeth became more present within the population. At generation 10, only 56% of bunnies had short teeth and by the end of that generation, it decreased to 25%. At around generation 15, 100% of bunnies had short teeth. The number of bunnies alive at the end of the generation increased as short teeth decreased in the population.

Discussion:

The results of this experiment support the hypothesis that there will be a greater favorability of traits of each new generation of rabbits as their environment changes. In the control group, no change in favorability was observed due to the fact that there was no environmental change. In the first experimental group, the favorability of fur color changed from white to brown as wolves were introduced to the environment. This greater favorability of brown fur could be due to Darwin’s theory of survival of the fittest. The bunnies with brown fur were able to survive more wolf attacks than the white-furred bunnies, therefore brown fur became the favored trait for survival. Similarly in the second experimental group, the favorability of teeth length changed from short to long as tough food conditions were introduced. To aid in survival the bunnies adapted to longer teeth to get more food in their environment. As generations continued, the trait favoring longer teeth became more prevalent as more bunnies with longer teeth survived the tough food conditions. The results proved our hypothesis that there will be greater favorability of certain traits as the environment changes, usually the traits that aid in survival are selected.

Conclusion:

The aim of our lab was to find whether environmental changes favor certain traits more than others as the new generation emerges. We learned that the introduction of wolves increased the darker color fur in the rabbit population. Moreover, the availability of tough foods increased the longer teeth rabbit population. These findings directly correlate with Darwin’s theory of natural selection. As nature changes, species with favorable traits survive often leading to a decrease in the species with unfavorable traits. Even though this experiment was thorough using the simulation, more empirical evidence would complement the findings of this article. For example, DNA responsible for changing color of the fur and changing the shape of the teeth would be helpful in predicting dominant and recessive traits for a given experiment.

In these second set of figures, the environmental factor was changed from wolves to tough food. This had affected the teeth mutation of the bunnies over generations. Once again, when looking at the proportions below, it is clear that over time more and more bunnies had longer teeth because it allowed them to eat tougher food, thus helping them survive.

References:

Natural Selection. National Geographic Society.

Natural Selection | National Geographic Society

What is Darwin’s Theory of Evolution? Ker Than, Ashley P. Taylor, Tome Garner published November 30, 2021
Darwin’s Theory of Evolution: Definition & Evidence | Live Science