What is Natural Selection?

Background Information:

Natural selection is one of the basic mechanisms of evolution and can be described as the process in which organisms that are better adapted to their environment tend to survive and reproduce more offspring. To understand Natural Selection, we must also understand the concepts of descent with modification and common descent. Descent with modification implies that when reproduction occurs, there will be slight differences from their parents due to random genetic mutations. Common descent describes how a group of organisms share a most recent ancestor.

Purpose:

To understand the evolution of organisms through natural selection.

Required Materials:

• 1 piece of green paper • 1 piece of beige paper • 20 normal toothpicks • 20 green toothpicks • Stopwatch • Tweezers • Notebook • Pencil • Thin Bubble Wrap • Laboratory Goggles or Safety Glasses

Procedure:

1. Mix the green and normal toothpicks together and randomly spread them out on the beige piece of paper. 2. Set up a stop watch for 20 seconds. 3. Start the clock and pick up as many toothpicks with the tweezers as you can. 4. Record the number of each color of toothpicks you collected in the table below. 5. Repeat the experiment on the green piece of paper and collect results. 6. Finally, put on the laboratory goggles or safety glasses and place the thin sheet of bubble wrap underneath to represent impaired vision and repeat the experiment on the green and beige paper.

Good Vision Impaired Vision (without goggles) (with goggles and bubble wrap) Green Paper Beige Paper Green Paper Beige Paper # of Toothpicks # of Toothpicks

Observation:

The green and beige papers are used to represent two different types of landscapes (grass and sand). The toothpicks represent a worm species that has different appearances and the tweezers represents a bird’s beak. Your first two results should be relatively balanced, but when testing the experiments with impaired vision your results should be one sided.

Results/Critical Thinking:

• When a bird has impaired vision is it easier for them to eat the worms that match the landscape or the worms that are contrast to the surroundings? • What would happen to the beige worms in the grass over time? • Explain how natural selection might have produced the modern day giraffe from its short-necked ancestors.

Conclusion:

Natural selection is known as survival of the fittest. The organism’s traits that represent the strongest attributes for the environment will thrive, while the less fortunate organisms will be phased out by natural selection. This is why the same organism species can differ based on the environment. Natural selection is one of the cornerstones of modern biology and explains genetic drift between species overtime.

Educational Video: https://www.youtube.com/watch?v=0SCjhI86grU

References: https://www.youtube.com/watch?v=W4FB6h0R1H8

http://evolution101.yolasite.com/natural-selection.php

https://www.khanacademy.org/science/biology/her/evolution- and-natural-selection/a/darwin-evolution-natural-selection