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| Overview |
| Grade Level: 9-12 |
| Background Information:
Evolution by natural selection occurs because there are outside
forces that act upon individuals in species. These forces can be
abiotic (e.g. climate) or biotic (other organisms). Organisms impact
each other. Co-evolution is a change in the genetic composition
of one species (or group) in response to a genetic change in another.
More generally, it encompasses the idea of some reciprocal evolutionary
change in interacting species. Co-evolution can be seen in a variety
of ecological relationships and can be either negative, as in predator/prey
and host/parasite relationships or positive as in the case of mutualism.
In 1862, Charles Darwin visited Madagascar where he saw an orchid
that had a tube that was 10 inches long before the nectar was reached.
He postulated the existence of a moth with a tongue that was also
10 inches long based on his understanding of evolution. Forty-one
years later, the moth was found, exactly as predicted.
Co-evolution can account for much of the great diversity of insects
on earth. In this lesson, students will learn about co-evolution
of mutualistic relationships while studying the roles of pollinators
and plants.
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| Content Standards |
| Related National Standards
This lesson addresses the following National Content Standards
found at: http://books.nap.edu/html/nses
Content Standard C: As a result of their activities in grades
9-12, all students should develop an understanding of:
- Biological Evolution
- Species evolve over time.
Evolution is the consequence of the interactions of
(1) the potential for a species to increase its numbers,
(2) the genetic variability of offspring due to mutation
and recombination of genes, (3) a finite supply of the
resources required for life, and (4) the ensuing selection
by the environment of those offspring better able to
survive and leave offspring.
- The great diversity of organisms
is the result of more than 3.5 billion years of evolution
that has filled every available niche with life forms.
- Natural selection and its
evolutionary consequences provide a scientific explanation
for the fossil record of ancient life forms, as well
as for the striking molecular similarities observed
among the diverse species of living organisms.
- The millions of different
species of plants, animals, and microorganisms that
live on earth today are related by descent from common
ancestors.
- The Interdependence of Organisms
- Organisms both cooperate and
compete in ecosystems. The interrelationships and interdependencies
of these organisms may generate ecosystems that are
stable for hundreds or thousands of years.
- Living organisms have the
capacity to produce populations of infinite size, but
environments and resources are finite. This fundamental
tension has profound effects on the interactions between
organisms.
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| Extension Web Sites
from PBS: |
|
Scientific
American Frontiers - Bee Lines
How do bees tell each other where to find nectar? This site will
illustrate the complex dance that bees use to describe the location
of a food source.
Scientific
American Frontiers - Flying High
What good is the nub of a wing? In this activity, students will
learn how insects developed the ability to fly in the first place.
The
Living Edens - Namib
Learn how insects have adapted to harsh conditions in the desert.
Scientific
American Frontiers - Champion Chompers
In this site, students will learn about a co-evolutionary relationship
in which ants farm fungi.
Scientific
American Frontiers - Science 911: Panama Protection Racket
In another example of a co-evolutionary relationship, ants protect
caterpillars from wasps in return for nectar.
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| Activity 1: The Sex Lives of
Flowering Plants |
| Time Allotted:
45 minutes
Materials:
Students will need to bring 10 flowers in from home. The teacher
may want to have extras to supply students who forget.
A diagram illustrating the parts of flowers, check out one of
these two websites for diagrams and a brief introduction to pollination.
Enchanted Learning: Flower Anatomy
The
Great Plant Escape: Flower Parts
| Objectives: |
- Students will compare and contrast features of flowers
to become familiar with flower morphology.
- Students will learn about the mutual benefits of pollination
for flowers and pollinators
- Students will predict which flowers are associated with
similar pollinators based on their own observations and
a basic understanding of co-evolution.
- Students will understand the importance of maintaining
the diversity of pollinators.
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| Teaching Instructions: |
- Begin the lesson by having students do a short journal
writing activity on the following question: Why are flowers
so different from each other?
|
Watch the AFG Video Segment:
 |
Plant
Reproduction
In
order to reproduce, plants depend upon insects or other creatures
for pollination - a very important process that is often overlooked. |
| Discussion Questions for Video Segment |
- Why are pollinators so important to flowers?
- Why are pollinators so willing to do all the work of pollinating
flowers? What is in it for them?
- Why are a variety of pollinators so important to our ecosystem?
|
| Lab Activity |
- Students should bring in 10 different flowers from home
or from nearby.
- Students should work in groups of two.
- Instruct students to look at the flowers, comparing and
contrasting features of the different flowers.
- Discuss some of the similarities and differences that
they found.
- Introduce the concept of co-evolution.
- Ask them to make a table listing 5 characteristics of
the flower. Some examples might be length of the corona,
number of petals, number of stamen, whether there is one
flower per stem or many, symmetry, color, smell, size, time
of bloom, length of bloom, etc. They should include a blank
column in their table for use in Activity 3.
- Students should then attempt predict which flowers the
same types of pollinators pollinate. For instance, flowers
with multiple flowers per stem, little scent, and red to
orange colors might fall into one category; flowers with
long tubular coronae and blue/purple colors may fall into
another.
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| Assessment Suggestion |
| Have students self-assess their
work by completing Activity 3 to identify common pollinators. |
|
| Activity 2: Comparing Moths
and Butterflies |
| Time Allotted:
20 minutes
Materials:
Projection capabilities for AFG video
| Objectives: |
- Students will understand that insects and flowers are
adapted to each other through co-evolution.
- Students will compare and contrast the feeding behaviors
of moths and butterflies.
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| Teaching Instructions: |
- Discuss: What is the difference between moths and butterflies?
- Tell students to imagine that they are naturalists studying
the behaviors of insects. The following video clips show
moths and butterflies eating. Students should make visual
observations as well as listening to what the video says.
A valuable exercise might be to turn the sound off and have
students make purely visual observations.
- Students should have pen and paper handy to jot down five
characteristics of each as seen in the following videos.
|
Watch the AFG Video Segments:
|
Researching
he Feeding Habits of Moths - Part 1
Researchers
collect floral scents and use camera equipment to study how
and why moths are attracted to certain flowers. |
|
Note: Start at the beginning and stop after hearing 'we will
be able to generate a 3-D reconstruction of the animals movement
and analyze it.'
|
|
Researching
the Feeding Habits of Moths - Part 2
Researchers
use powdered day-glo paint to help them observe how moths feed
on and pollinate flowers. |
|
Note: Clip starts at 'this is the long coiled up tongue…'
Watch through to the end.
|
|
Paynes
Prairie, Florida - Butterflies
The
moist environment of a hardwood hammock draws numerous butterflies,
including sulfurs, skippers and a gulf fritillary.
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|
Note: Start at the beginning and stop after hearing 'an average
lifespan for most of the butterflies'
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|
| Activity 3: The
Secret Lives of Pollinators |
| Time Allotted:
45 minutes
Materials:
Students should have 10 flowers each and a table of flower characteristics
from Activity 1.
A copy of the lab manual of common pollinators for each group.
To make a lab manual, go to Coevolution
website. About two thirds of the way down through the document,
you will find a section that begins with "Adaptations of flowers
depend on the type of pollinator on which they depend". Information
about the specific behaviors of different pollinators follows. Print
out these pages as a lab manual, or make this page available for
student use. (note, the whole document is very informative with
regards to this topic. In the absence of appropriate text, you might
have students read through this entire site.) Janet Stein Carter
of the University of California produced this material.
| Objectives: |
- Students will learn about adaptive characteristics of
pollinators
- Students will use their knowledge of co-evolution to predict
specific matches between pollinator and flower.
|
| Teaching Instructions: |
- Brainstorm common pollinators (e.g. bees, wasps, hummingbirds,
butterflies, bats, beetles, flies or moths)
- Instruct the students to create a hypothesis, based on
their knowledge of insects and other pollinators and their
knowledge of co-evolution, about which specific pollinators
might be associated with each flower.
|
Watch the AFG Video Segments:
|
Wide
World of Pollinators
Bees,
hummingbirds, moths and bats are just some of the creatures
that pollinate the flowering plants of the world. |
| |
- Using the Lab Manual, students should attempt to determine
which types of insects pollinate which flowers.
- Have students select one of their flowers to present to
the class. They should explain which type of pollinator
they think uses it and why.
- Journaling Activity: Why are flowers so different from
each other?
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| Assessment Suggestions |
|
Compare the journal writes from activity 1 and activity 3
to assess student learning.
Assess the student presentation to the class using the following
scoring guide on the PDF version of
this lesson plan
OR
Have the students choose one flower to write a one-page report
explaining a co-evolutionary relationship and assess using
the scoring guide
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