Summary: The Influence Of Natural Selection

The purpose of this lab was to figure out how natural selection gave some birds advantage in picking up food. According to Darwin, Natural selection was a process in which “tiny variations were selected by virtue of whether or not they helped organism survive” (Wyhe, 2016). In Darwin’s voyage to the Galapagos islands, he discovered finches with different beak size that still somewhat resembled one another. Adaptive radiation was used to describe this concept because the finches all came from one common ancestor but developed variation based on the environment and food supply available. Birds that were generalist survived on variety of foods, while specialist “suffered decline under environmental changes” (Colles et al., 2009).
In this experiment, four different birds were studied with different beak sizes to determine if they were generalist or specialist and how they would be effected by the environment if certain foods disappeared. Common items such as scissors, binder clip, spoon, and tweezer were used to represent the different beak
shapes in the experiment. Scissors represented Huxley’s sparrow’s beak, binder clip represented Henslow’s sparrow’s beak, spoon represented Emma’s sparrow’s beak and lastly tweezer represented hooker’s sparrow’s beak. If spoon is used to pick up food, then more food will be gathered because spoons are somewhat hollow object which enables them to pick up a large amount of foods in short amount of time.
Materials/Methods
A pair of small scissors were used to pick up and place paperclips in a Styrofoam cup for 20 seconds.
Only one hand was used to pick up the material while the other hand held the cup. Afterward, the number of paperclips in the cup were recorded. Scissors represent Huxley’s sparrow’s beak shape in the experiment. Then, the same scissors were used to pick up and place unpopped popcorn in Styrofoam cup for 20 seconds. The picked up popcorn were also recorded. Next, the scissors were used to pick up and place rubber bands in Styrofoam cup for 20 seconds. The answer was also recorded. Scissors were used to pick up and place lima beans in cup for 20 seconds and the answer was recorded. Lastly, the scissors were used to pick up and place marble in Styrofoam cup and the numbers of marbles picked up were recorded. During the last part of this experiment, the other students in the group helped keep the marbles from rolling off the
table.
Similarly, binder clip, which represent Henslow’s sparrow’s beak, was used to pick up and place paperclips in Styrofoam cup for 20 seconds. The other four items, popcorn, rubber band, lima beans, and marbles, were also picked up using binder clips for 20 seconds and the answers were recorded. The same procedures as above were repeated with spoon, which represent Emma’s sparrow’s beak, and tweezer which represent Hooker sparrow’s beak.
Huxley’s sparrow picked up 63 paperclips,45 unpopped popcorn,106 rubber bands, 19 lima beans and zero marbles. Henslow’s sparrow picked up 12 paperclips, 131 unpopped popcorn,113 rubber band, 97 lima beans, and 45 marbles. Emma’s sparrow picked up 30 paperclips, 630 unpopped popcorn, 97 rubber bands,159 lima beans and 23 marbles. Hooker’s sparrow picked up 98 paperclips, 68 unpopped popcorn, 161 rubber bands 50 lima beans and 10 marbles.