本文是留学生入学coursework范例，题目是“Natural Selection Experiment: Darwin's Finches（自然选择实验:达尔文雀）”，查尔斯·达尔文经常被认为是进化之父。他的加拉帕戈斯群岛之旅，在那里他观察了多种物种，其中之一是雀类，现在在科学界很出名。当时，他并没有真正记录下他所看到的东西，直到他在欧洲的航行结束后，他真正研究了他的笔记(《进化:图书馆:适应性辐射:达尔文雀》)，他才意识到这一点的重要性。
a. Charles Darwin is often credited for being the father of evolution. His trip to the Galapagos islands where he observed multiple species, one of which were finches, is now famous among the scientific community. At the time he didn't really make note of what he was seeing, he didn't see it as significant until after his voyage when he actually studied his notes back in Europe ("Evolution: Library: Adaptive Radiation: Darwin's Finches").
The finches he studied are usually defined as 15 different species that all diverged from a single species of bird (Funk & Burns 2018). Every species of bird has a specific type of beak used to eat a specific type of food, for example there was one with a long sharp beak good for eating insects, and another with a shorter rounder beak good for eating cacti (Cromie 2016). These observations helped lay the foundation for the theory of evolution by natural selection.
他研究的雀类通常被定义为15种不同的物种，它们都是从一种鸟类进化而来的(Funk & Burns 2018)。每种鸟类都有一种特定类型的喙，用来吃特定类型的食物，例如，有一种长而锋利的喙适合吃昆虫，另一种短而圆的喙适合吃仙人掌(Cromie 2016)。这些观察结果为自然选择进化论奠定了基础。
We as a class demonstrated this theory of natural selection by doing an activity that simulated evolution by testing out tools or "beak types" that were best suited for the food that was available to the tool holders. We did this multiple times to show adaption by allowing the top performing tool holders to reproduce, and over multiple generations these adaptations simulated populations reproducing while the ones that couldn't eat the food died out.
i. My initial hypothesis was that the chopstick group would die out the fastest.
ii. I had experience with chopsticks before this experiment, from my prior experience I knew that it's difficult to pick up small things with them. The seeds we had to pick up were small so I assumed chopsticks would have the hardest time picking them up.
Materials and Methods材料和方法
a. For materials we used tongs, clothes pins, chopsticks, tweezers, hair clips, chip clips, sunflower seeds, small paper cups, tables, a timer, and a graph to keep track of things.
b. In this activity we started with 30 people, all of which were divided up into 6 groups with 5 members in each group. Everyone in the experiment was sitting at a table, each table had about 2 people at it. Everyone was also given a small paper cup. Each member in each group of 5 were given a tool to simulate a beak. All five members of group 1 were given tongs, all five members of group 2 were given clothing pins, all five members of group 3 were given chopsticks, all five members of group 4 were given tweezers, all five members of group 5 were given hair clips, and all five members of group 6 were given chip clips.
After the tools were distributed there were sunflower seeds that were poured in front of everyone. The seeds were sprinkled somewhat evenly in front of everyone. After this a timer was set up for 1 minute. Everyone was given an objective, which was to pick up as many seeds as possible one at a time with the tool given before the timer ran down to 0. After the timer is finished the seeds were put into the paper cups and poured back out again to reset the activity. This was repeated 6 times, and everytime it was done the top 3 people in the class got to "reproduce" while the bottom three members died off. The way this was done is that the professor running the whole experiment would find the 3 people that collected the most seeds and put them in a group, after this she'd find the bottom 3 people and put them in a different group. After this the bottom three people were "killed off" so to speak. They had their tools taken and then were given the same tools the top three people had so the top three people "reproduced", after this they were sent back to their seats. This process was repeated 6 times, and every time it was done the number of every species was recorded on a graph. After this was finished we counted up the members of every group on every generation to see whos hypotheses were correct.
c. The results of this were that the tongs group were the most successful, they reproduced the most and ended the activity with 9 members of their group. The clothes pins didn't do too good, they ended the activity with 2 members of their group. The chopsticks group as predicted died out the fastest, there were 0 of them by generation 4. The tweezers did pretty good, they got up to 7 members of their group and it stayed consistent throughout the activity. The hair clips did alright, they got up to 6 and stayed there until the end of the activity. The chip clips seemed to fluctuate, for multiple generations they went back and forth between 5 and 6 members of the group.
My hypothesis was correct. The chopstick group did die out the fastest. They got to 0 by the 4th generation. In fact, they were the only group that completely died out. Possible errors that could be fixed in future replications of this experiment would be the possibility of the participants lying about whether or not they picked up the seeds one at the time, miscounts, participants collecting seeds before the timer starts or after it ends, participants lying about the number of seeds they really have, the definition of a "whole seed" was never defined, there could be more but these were just the ones I could think of. If others replicate this experiment in the future they would help validate or invalidate the results of this version of it. They could either have similar results which would validate my hypothesis, or they could have different results which would invalidate my hypothesis. It's hard to say whether or not my hypothesis would hold up since we only did one round of this activity.
The scientific method involves first making an observation, then coming up with a question about that observation, after that is to make a possible answer to the question or a "hypothesis", next is to make a guess based on the hypothesis, after this the guess is tested, then finally a conclusion is made that either supports or goes against the hypothesis.
Another field that uses the scientific method is the technician field. For example, I am currently taking a computer maintenance class, and computer technicians are told to follow a similar model when it comes to repair something. First we must identify what has changed, then come up with a possible explanation for the change, after this the explanation is tested. If the explanation ends up being correct then the problem is fixed, if it's wrong then the process is repeated until the true explanation is found.
This activity demonstrates the use of the scientific method by having me make an observation which was first noticing the different tools that were used to pick up the seeds, next was asking a question which was "which group of tools would die out the fastest?, after this my hypothesis was that the chopsticks group would die out the fastest, then this hypothesis was tested and turned out to be correct. So the conclusion I made was that the chopsticks did die out the fastest so they're the least efficient at picking up seeds.
The theory of evolution by natural selection states that organisms with traits more suited for their environment will survive, while organisms that are less suited for their environment will die off. Evolution takes place as this happens over many generations. The underlying assumptions for this are that there are inheritable variations among populations, there are more members of a population that are born than can survive and reproduce, organisms with adaptive characteristics are more likely to survive and reproduce in an environment, a population can gradually adapt to an environment over a long time, and the endto evolution results in many different and diverse species each adapted to a specific environment ("Darwinian Evolution").
This activity simulated the theory of evolution by demonstrating the idea that organisms with better adaptations or "tools" suited for their environment will survive longer and reproduce while organisms that are less suited for the environment or have lesser suited "tools" die off. The evolutionary outcome that came from the activity was that the tongs successfully reproduced and had the most members of their population by the time the activity was over.