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*** DO NOT use Arizona Sonoran Desert
Museum, Tucson Botanical Garden, or any other protected park for these
collections -- pay attention to restrictions against collecting***
Students will learn about native desert
plants through collecting and identifying plant specimens.
ADAPTATION
see also Desert Plant
Adaptations Lesson
This project can be used to help students to see the various ways
that plants are able to adapt to desert conditions. Many plants adapt to the
arid heat of the desert by having smaller leaves or no leaves at all. Leaves
often lose water by evaporation; by reducing the amount of surface area affected
by evaporation, plants are able to conserve water. This can be seen on
succulents, cacti, palo verde, mesquite, as well as many other plants. Several
of these plants have green stalks and bark which can be involved in
photosynthesis in place of leaves. Flowering plants may have smaller
flowers for a similar reason.
DIVERSITY
Plants can also have a wide diversity in design in order to utilize different
niches in the ecosystem. Plants may have different types flowers, which
will be open at different times of day, based on the their mode of
pollination. Saguaros, which attract bats, have much larger flowers which
open at night, than ocotillos, which attract hummingbirds and have small, red
tubular flowers.
STRUCTURING THE COLLECTION / ASSIGNMENT
--The reason behind assigning this project should be well understood before
beginning the collection, so that students know what they should be looking for
and learning while completing the project. Necessary background, such as the
previously listed lesson objectives should be taught before students are to
begin collecting.
--Assign a specific number of plants to collect, varying based on how much time
you want to devote to this project.
-- Explain the collecting techniques to students.
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A field notebook is a helpful way for students to keep track
of the plants that they collect and the data about the plants.
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Each plant receives a number when collected, it keeps this
number through the entire project.
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When collected, describe the plant, presence of leaves or
flowers, leaf size and shape, flower size and shape, color, in case the color fades or something else happens, making it
difficult to identify later. Students should be sure to describe the entire
plant, in case their specimen is only a small piece of a larger plant (ie:
leaf or stem off a tree or bush).
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Record date collected as well as area, ie: park or
neighborhood, county, state.
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Leave space to add the common and scientific names of the
plant, as well as other data, such as range, growing season, whether it
flowers.
This information can be found in plant identification books.
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All of this should be done at the time of collection, memory
is not always accurate and plants specimens may not always remain exactly
the same as when collected.
--Collect native plants only, not planted plants, in other words: don't pick plants out of gardens.
This project is intended to help students learn about the native plants of
the desert, garden plants are rarely native. Because of this, students
will need to be given suggestions as to where they can collect appropriate
plants. In the Field Trip section,
there are several suggestions of places to take classes, some of these may be
appropriate for plant collection. Be sure to contact these places before
collecting plants there to ensure that it is acceptable. Students need to be
aware of restrictions against the collection of plants in parks and protected
areas. It may be helpful to take a class trip to collect plants.
-- Press plants. A plant press can be built, by cutting 2 strong boards
to the same size and drilling holes for bolts at equal positions in all four
corners. Plants should be placed between sheets of newspaper (wax paper for
sticky plants, or plants with sap) and separated by corrugated cardboard, and
placed between the two boards. Bolts are placed in each of the holes and
tightened using wing nuts. Plants can also be easily pressed by placing
them between newspaper or wax paper and putting them within the pages of heavy
books or between large books.
-- Display plants by gluing them to a heavy white sheet of paper. Plants can
be protected either by laminating, placing in protective sheet covers, or using
spray glue and covering them with plastic wrap. Each plant should then have a
label telling the common and scientific names as well as range, season, and a
description of the plant and flowers if it is a flowering plant.
Identification books for reference:
Brown, Vinson. How to Make a Home Nature Museum. Boston: Little,
Brown, and Company, 1954.
Benchmarks for Scientific Literacy met
by this lesson:
The Living Environment,
5A Diversity of Life: grades 6-8
*Animals and plants have a great variety of body plans and internal structures
that contribute to their being able to make or find food and reproduce.
*Similarities among organisms are found in internal anatomical features, which
can be used to infer the degree of relatedness among organisms. In
classifying organisms, biologists consider details of internal and external
structures to be more important than behavior or general appearance.
Source:
Project 2061: American Association for the Advancement of Science. (1993) Benchmarks
for Science Literacy. New York: Oxford University Press.
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