Shannon Kelly
Dr. Warden
Educ 340
Lesson 2: Natural Selection
March 14, 2011
1.
Targeted Grade Level: 6th
2.
Scientific Processes Addressed: Evolution
3.
Science Topic Addressed: Natural Selection
4.
Process-Oriented Objective: The students will learn about natural selection. This is a
mechanism that could produce evolutionary change. They will understand the concept of “survival of
the fittest” and understand why animals or species that adapt to their environment will have a better
chance for survival and be able to produce more offspring.
5.
What I want the children to discover: The students will investigate and understand that species
must fight and struggle in order to survive and have to change to adapt to their environment.
6.
Description of introductory activity and initial discussion: Reading and Discussion
Today we are going to learn about evolution by way of natural selection. This is a mechanism that could
produce evolutionary change. There are three observations: In any species, more young are born than
survive and reproduce (“survival of the fittest”). Variation exists among the members of a population;
therefore, some variants will consistently and non-randomly produce more offspring than others. Some
of this variation is hereditable and most offspring will become the dominant of the population over
time. Thus, the heritable traits of a population will change over time, this is called evolution. We will
begin by first defining natural selection: which within a population is the nonrandom differences in
reproduction of individuals with differing traits or adaptations. Species: which is a class of individuals
with the same types of characteristics. Adaptation: adaption of change to be able to survive in your
environment. Evolution: a gradual process in which something changes into a different and usually
more complex or better form.
7.
Materials Needed: beans, plastic forks, spoons, and chopsticks or straws.
8.
Description of Activity: Today we are going to pretend to be crab-like predators that vary in the
shape of their claws. They use these claws for catching prey to eat and their claws come in three
variations: we are going to use spoons, forks, and chopsticks as our simulation. In this experiment,
individuals who catch more than the medium number of prey survive and are able to produce a new
offspring. Those who do not catch the medium number of prey die of starvation before reproducing.
There is an equal number of species per population. We will hunt for food for about thirty seconds each
time (less if needed). If the population dies then they lose their utensil and must become an offspring of
one who exceeds the medium. We will track the frequency of these three variants as we follow this
population through a few generations.
10.
How Children Will Be Encouraged To Investigate On Their Own: Give the students the freedom
to investigate on their own and then instruct them only after they have explored. Do not correct them
until after they have been given the opportunity to work on their own. Allow the student freedom to
compete with one another at the slightest extent before interfering.
11.
Expected Conclusion: The children will discover that the more advanced tools (in this case the
spoons) will be the best tools of survival. Children will understand the process of natural selection and
extinction and know that the species that are more able to adapt to their environment are the ones that
will survive and pass on their traits to their offspring and they will continue to evolve. They will
calculation and graph their findings.
12.
Assessment: Give the students the graph paper and allow them to graph the findings to see
which tools were the best for survival.
13.
Do a question and answer section after the graphs, review the definitions, and explain that this
process is why certain animals go extinct and why others prosper.
14.
Applications to Real-Life Situations: Many species today have to adapt to their environment.
Humans put on jackets when it is cold or have the ability to hunt for their own food. Birds have long,
hooked beaks that allow them to feed their young and search for food. The crab-like creatures that we
simulated have adapted their claws so they can compete and obtain the most food possible.
Natural Selection Simulation
Procedure:
1. Start with an equal population with each of the 3 variants (equal number of spoons, forks, and
chopsticks). We will use this as Generation 0.
2. The teacher will throw food on the ground. All predators will begin searching for food and
capturing it with their tools. The hunt will be over after about fifteen to twenty seconds.
3. Determine the median (middle) number of prey caught. All those that are below the median
will die without reproducing (turn in their utensil). All of those who are above the median line
will produce an offspring (Keep their own utensil, and get a replicate utensil to have to an
empty-handed classmate).
4. Census the population and determine the numbers of each variant. Record the results for each
generation and graph your results.
Before we begin make your own hypothesis of what you think will happen:
Place the data for the number of species in this table.
Forks
Spoons
Chopsticks
(straws)
Total
Generation 0
Generation 1
Generation 2
Generation 3
Generation 4
Graph your data. Place the number of each variant in the population in the y-axis, over the generation
(x-axis).
Questions
1. What has changed over time (generations) of the variants?
2. Is one variant more favored over others by natural selection? Which ones?
3. What about evolution? Has it occurred in this simulation?