Brian's
Class Materials- FALL 2009 - SEYS 362
SEYS 362
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Queens
College/CUNY
Education Unit
Fall 2009
Title : Dichotomous Key Delights (Mystery Leaves)
Grade levels : middle school and junior high school, grades 6-9
Subject areas : Biology, Living Environment
Instructional objectives :
- Students will be able to use an online interactive key to
identify common trees
- Students will be able to use print copy of a dichotomous
key to identify trees by their leaves
- Students will understand why taxonomy and identification of
trees is important
Materials:
- zip loc bags (4)
- 1 specimens of dogwood (branch with leaves attached)
- 1 specimens of pine (branch with leaves attached)
- 1 specimens of magnolia (branch with leaves attached)
- 1 specimen of sugar maple (branch with leaves attached)
- Tree Finder by May Theilgaard Watts (12)
- computers connected to the Internet with web browsers
- hand lenses (12)
- pencils (15)
- lined paper to record observations, sketches
- computer for the teacher with projector and screen
Safety precautions :
Mention that some plants are
poisonous. Show students images of poison ivy, poison oak, and poison
sumac. If you are not sure, ask the teacher before touching it,
What poison ivy looks like: http://www.poison-ivy.org/
Poison ivy in summer: http://www.poison-ivy.org/html/summer1.htm
Outsmarting poison ivy and its cousins: http://www.fda.gov/fdac/features/796_ivy.html
Images of poison ivy, poison oak, and poison sumac:
Procedure :
- Motivation: Why is it very important to be able to identify
plants?
- Poison ivy
- poisonous plants
- edible plants
- Students should then work in pairs or groups of three to
answer the following discussion questions:
- Why is it is important to be able to identify trees?
- After the discussion have the students visit a web site
with interesting information about trees: http://www.units.muohio.edu/dragonfly/trees.htmlx
- Tell
the students that today we will be identifying some mystery leaves and
after that we will start identifying all of the trees in our school
surroundings. This will be the first stage in doing a comprehensive
nature study of the school's surroundings. The first step is learning
how to identify trees.
- Each group should collect a
zip loc bag that contains mystery leaves attached to a branch. Their
task is to use the Tree Finder by May Theilgaard Watts to identify
their mystery leaf. Once you have finished exchange leaves with another
group. Don't tell other groups your results until everyone has had a
chance to key out all four leaves.
- The second activity will involve using an online
interactive nature guide to key out trees. Visit the following web site
http://www.discoverlife.org
and then click on IDNature Guides, then on Trees, Shrubs
& Vines , North America and click on the Help
link to learn how to use the web site.
- Go
outside and pick at least three different trees that have different
leaves from the mystery leaves. Make a sketch of your tree, its leaves
and bark, and record detailed observations. You can bring a small
sample of leaves on a branch but please make sure not to damage the
tree. You will use this information when you are back in the lab to
identify your tree. If there is a label and sign on your tree please do
not look at it now. Later you can go back outside and check your answer.
- After
all groups have finished, go over the identify of the mystery leaves.
If anyone had problems with the key, they can check the
mystery-leaves-hints web page.
- At the end of the class, discuss the following questions:
- What have you learned about trees and leaves?
- Which method was easiest to use, the online interactive
nature guide of the printed guide?
- How could you make a key to help people identify the
plants in your school environment?
Hints:
Please do not look at this until after you have keyed out your mystery
leaves
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