GK-12 Pre-Workshop Assignment
Introduction to Evolution and Biological Diversity
Author: Eric Tosso
A. Educational Standards Addressed
South Carolina Standard B- 5: The student will demonstrate an understanding
of biological evolution and the diversity of life.
South Carolina Standard B- 6: The student will demonstrate an understanding
of the interrelationships among organisms and the biotic and abiotic
components of their environments.
National Science Education Standard C: As a result of their activities in grades
9-12, all students should develop understanding of the cell, molecular
basis of heredity, biological evolution, interdependence of organisms,
matter, energy, and organization in living systems, behavior of organisms.
B. Performance Objectives
The following the South Carolina Scientific Inquiry Indicators addressed are:
B- 5.1 Summarize the process of natural selection.
B- 5.3 Explain how diversity within a species increases the chances of its
survival.
B- 5.4 Explain how genetic variability and environmental factors lead to biological
evolution.
B- 6.1 Explain how the interrelationships among organisms (including predation,
competition, parasitism, mutualism, and commensalism) generate stability
within ecosystems.
B- 6.2 Explain how populations are affected by limiting factors (including densitydependent, density-independent, abiotic, and biotic factors).
The following topics for The National Science Educational Standard C are
addressed:
Biological evolution
Interdependence of organisms
C. Lesson Plan Concept
1. Exploration (Day 1)
1. Give the students a hand-out (attached) with several questions on the
topic of biological evolution and biodiversity. These will be completed
individually so that the instructor can asses the each students knowledge
of the subject prior to the exercise. (~15 minutes)
2. Introduce the students to some examples of animals that have taken an
interesting evolutionary turn. (~10 minutes)
3. Introduce the topic of biological evolution and biodiversity as well as some
of the key terms / names that are associated with the topic: Charles
Darwin (“On the origin of species”), natural selection, competition,
predation, and resource limitation etc. It should be stressed that multiple
factors drive the evolution of a species: genetic mutation, environmental
factors: abiotic (i.e., avg. annual rainfall), and biotic (i.e., predation). (~30
minutes.)
2. Introduction (Day 2)
1. Briefly review the material from the previous class period. (~10 minutes)
2. Natural selection field activity – “Natural Selection and Evolution – It’s All
About Love.” (~40 minutes)
3. As homework, ask the students to think about the preliminary results from
the field activity and come up with some hypotheses about what happened
to the population. Some potential questions to be addressed in this
assignment:
What “trait” was most desirable at the beginning of the exercise?
Which “trait” was most desirable at the end?
If this changed, what factor(s) caused this change in selection?
3. Application (Day 3)
1. Another review on natural selection, evolution. The hypotheses generated
the previous day will be displayed. (~10 minutes)
2. Data from the previous day will be analyzed a presented graphically to the
class. The students will be asked (classroom discussion) to interpret the
data and whether this supported of refuted their hypotheses. (~30
minutes)
3. The post-quiz will be administered. This could be a take-home assignment
if time runs short. (~15 minutes).
D. Review / Evaluation
Performance on the post-quiz and classroom discussion will be used to
gauge the success of this exercise and ensure that the appropriate indicators
have been demonstrated.
________________________________________________________________
Introduction to Natural Selection and Evolution
Pre-Quiz
Please answer the following questions to the best of your ability. You will not be
penalized for incorrect answers; this is merely to gauge your knowledge of the
material prior to instruction.
1) What is the difference between natural selection and evolution?
2) List three things that limit the number of individuals that can occupy any given
area at one time.
3) Are bears near the Arctic bigger than near the Equator? Why?
________________________________________________________________
Introduction to Natural Selection and Evolution
Post-Quiz
Please answer the following questions to the best of your ability.
1) Who is credited with developing the Theory of Evolution?
2) What is biological diversity? Give some examples.
3) What is the definition of “species”?
4) How could biological diversity increase the chance of a species’ survival?
5) The evolution of a species occurs over the course of many generations as
a result of natural selection. Please explain how genetic variability and
environmental factors play a part in natural selection.
6) The stability of an ecosystem depends in large part on the
interrelationships among the organisms found within it. Among these are
parasitism, mutualism, and commensalism, predation, and competition.
Please define as many of these terms as you can.
Field Exercise – Teacher’s Copy
“Natural Selection and Evolution – It’s All About Love”
Objective:
The goal if this exercise is to familiarize the students with the effects of sexual
selection, genetic variability, and environmental changes on a population. To
accomplish this, students will act out roles as members of a fictitious animal
species. Males and females will be given randomly assigned “traits” that
represent some level of fitness within the population. They will then act out
several trials (seasons) under differing levels of biotic and abiotic stress in order
to examine how these factors can cause shifts in the ratio of genotypes
(microevolution) and phenotypes (macroevolution) within a population.
Materials Needed
1. Party hats
2. Noisemakers
3. Beaded necklaces
4. Plastic army men, candy, or some other material that can be
purchased in bulk inexpensively (these will serve as offspring)
5. Container to hold ornament assignments for random drawing
6. Cape (predator)
7. Computer equipped with Microsoft Excel or a similar spread sheet
program capable of producing graphical output.
Students are divided into groups of males and females and randomly choose the
types of ornamentation they will wear for the exercise.
Males:
There are four male genotypes / phenotypes possible at the beginning of this
exercise:
1. No ornaments = least desirable
2. Hat = moderately desirable
3. Noisemaker = moderately desirable
4. Hat + noisemaker = most desirable
Females:
There are two female genotypes / phenotypes possible at the beginning of this
exercise:
1. No necklace = low fecundity
2. Necklace = high fecundity
At the beginning of each season (trial), the females will be separated from the
males and secretly told what “traits” are most desirable. They will then go into
their habitat (classroom, gymnasium, football field, etc.) to wait for the males to
come in. When the males go into the habitat, they will approach the females and
attempt to “mate”. If the female accepts the male, he will give her the appropriate
number of “offspring”.
Each male may be paired with two females during the course of one season.
This will replicate the difficulty of males finding receptive females in nature. Each
season will last approximately 3 minutes (this will vary with class size, but it
should be short enough that students will need to be quick in making their
choices and weigh the costs and benefits of waiting for a more desirable male or
accepting one that is less acceptable so that at least some offspring are
ensured). As in nature, the ultimate goal here is to produce offspring to carry on
your genetic material – it does the students no good to be too picky in their mate
selection.
Male / Female Fecundity:
1. Male w/ two ornaments + Female w/ ornament = 5 offspring
2. Male w/ two ornaments + Female w/ no ornament = 4 offspring
3. Male w/ one ornament + Female w/ ornament = 4 offspring
4. Male w/ one ornament + Female w/ no ornament = 3 offspring
5. Male w/ no ornament + Female w/ one ornament = 2 offspring
6. Male w/ no ornament + Female w/ no ornaments = 1 offspring
Once the male students have found a female, she will accompany him for the
rest of the season. This will replicate the territoriality of some males in the wild
and make it easier to count offspring at the end of the season. At the end of each
season, the students will gather with their mates at a common location so the
pairings and number of offspring can be recorded by the instructor. These data
will be entered into Excel (example attached) so that population trends can be
analyzed for the next class period.
The number of seasons will vary depending on the time available and the
number of selection factors (predators, disease, natural disasters) introduced by
the teacher. The idea is to allow students to perform a couple seasons with only
sexual selection first. In this way, they can see the results of one trait being
dominant and occurring more often in the offspring. Then, different selection
pressures can be added (a new predator or disease that preys almost exclusively
on males with hats and noisemakers) to show the students how other factors can
change definition of “fitness” within a population.
A few rules and logistical items:
1. Once a male and female “mate”, they must remain together for the
duration of that season. There is to be no fighting between the males.
2. Each male is only allowed two females per season.
3. The number of offspring for the entire season will be tallied; 50% will be
considered to be males, 50% will be considered females. For simplicity,
we are only tracking the traits of males in this population. Female offspring
will only be used to track the total population size.
4. For simplicity, the number of breeding-age adults will be kept constant
throughout the exercise.
5. The method for determining the number of offspring possessing each
genotype / phenotype is as follows:
(Xa / T) * M
where Xa = number of offspring conceived by genotype a
T = the total number of offspring conceived that season
M = the number of males conceived that season
Sample exercise:
For this example, we will use a class of 15 students (7 males, 8 females). Four
females will have necklaces (n) and four will have no necklace (o). Three males
will have hats & noisemakers (H/N), two will have only hats (H), one will have a
noisemaker only (N), and one will have no ornament (0).