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Allan Strand asked about inquiry-based labs on plant diversity. Tough
question! Unfortunately, students can't really tackle the most interesting
questions until they have a grasp of the diversity. Nevertheless, we must
find ways of introducing the material in a much larger context to bring
them eventually to that understanding. Trying to move to inquiry -based
labs rather than rote memorization is the key. Here are a few suggestions
to make the labs more interesting and somewhat more inquiry-based:
1) Focus on the big picture... that plants are moving from aquatic to
terrestrial environments. While studying any life cycle, try to
observe/hypothesize/draw conclusions to questions like: [in no particular
order]
Can the organism move freely from place to place in this habitat?
What basic biological functions are affected by restricted movement of the
organism? (Ans: virtually all!)
How harsh is this environment on various stages of the life cycle?
What adaptation(s) might help various stages of the lc to survive
in a drier habitat?
Describe the nutrition (autotrophic/heterotrophic) of each stage of lc.
Describe the degree of "division of labor" (cellular diversity) in
this organism and compare it to others.
Is the gametophyte generation free-living or retained within the
sporophyte body?
How well are the gametes protected?
How do gametes meet one another to bring about fertilization?
Do gametes move or do spores (e.g., pollen grains) move or both?
How does the plant body absorb and transport water?
Compare the adaptive advantage of the fruit (angiosperm) vs. cone
(gymnosperm). (and other similar questions)
Students are more interested in finding answers (constructing knowledge)
than in memorizing the names of the various structures/stages of the life
cycles. But, of course, in answering the questions, they will inevitably
pick up the terminology because it is very difficult to write answers
saying "this thing then moves to this thing"!!!
2) Have the students use modern technology to get at some of this information:
* use videodiscs for life cycles. You can write a narrative (or
adapt an existing lab exercise) then insert barcodes which the students can
"zap" as they move through the narrative, seeing the photo or movie on the
monitor. See Kramer, David W. 1991. Interactive biology with videodisc.
Amer. Biol. Teacher. 53(3): 185-188.
* for each type of plant, give the students links to the WWW where
they can learn more about each plant. Better yet, have the students
(perhaps working in teams) compile a list of annotated (they have to write
2-3 sentences telling what one can find at each link) links to useful
information on each plant. In the process of gathering the links they will
learn much about the plants.
3) While studying each group, bring in fossil evidence. My students are
fascinated to see some actual fossils of Calamites, Lepidodendron, etc.
when we study those groups. We also "extract" fossil plants from coal
balls and they are amazed that you can see cellular detail in ~350 million
year old plants!
4) Culminate the plant diversity unit with a study of the mechanisms of
evolution. By the time you get to that unit, the students are bursting
with questions about how all the different plants arose. If you have
introduced the fossils, they already have the evidence of evolution not to
mention the evidence gleaned from their comparative morphology studies.
In summary, morphological studies need to have a purpose if you expect
students to embrace the topic. We are fascinated by life cycles mainly
because we have the advantage of understanding them in a larger context.
That's why we have to teach them in a larger context.
*********************
David W. Kramer, Ph.D.
Asst. Prof. of Evolution, Ecology, and Organismal Biology
Ohio State University at Mansfield
1680 University Drive
Mansfield, OH 44906-1547
Phone: (419) 755-4344 FAX: (419) 755-4367
e-mail: kramer.8 at osu.edu
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Allan Strand asked about inquiry-based labs on plant diversity. Tough
question! Unfortunately, students can't really tackle the most
interesting questions until they have a grasp of the diversity.
Nevertheless, we must find ways of introducing the material in a much
larger context to bring them eventually to that understanding. Trying
to move to inquiry -based labs rather than rote memorization is the
key. Here are a few suggestions to make the labs more interesting and
somewhat more inquiry-based:
1) Focus on the big picture... that plants are moving from aquatic to
terrestrial environments. While studying any life cycle, try to
observe/hypothesize/draw conclusions to questions like: [in no
particular order]
Can the organism move freely from place to place in this habitat?
What basic biological functions are affected by restricted movement of
the organism? (Ans: virtually all!)
How harsh is this environment on various stages of the life cycle?
What adaptation(s) might help various stages of the lc to survive in a
drier habitat?
Describe the nutrition (autotrophic/heterotrophic) of each stage of
lc.
Describe the degree of "division of labor" (cellular diversity) in
this organism and compare it to others.
Is the gametophyte generation free-living or retained within the
sporophyte body?
How well are the gametes protected?
How do gametes meet one another to bring about fertilization?
Do gametes move or do spores (e.g., pollen grains) move or both?
How does the plant body absorb and transport water?
Compare the adaptive advantage of the fruit (angiosperm) vs. cone
(gymnosperm). (and other similar questions)
Students are more interested in finding answers (constructing
knowledge) than in memorizing the names of the various
structures/stages of the life cycles. But, of course, in answering the
questions, they will inevitably pick up the terminology because it is
very difficult to write answers saying "this thing then moves to this
thing"!!!
2) Have the students use modern technology to get at some of this
information:
* use videodiscs for life cycles. You can write a narrative (or
adapt an existing lab exercise) then insert barcodes which the students
can "zap" as they move through the narrative, seeing the photo or movie
on the monitor. See <fontfamily><param>Helvetica</param>Kramer, David
W. 1991. Interactive biology with videodisc. <italic>Amer. Biol.
Teacher</italic>. 53(3): 185-188.
</fontfamily>* for each type of plant, give the students links to the
WWW where they can learn more about each plant. Better yet, have the
students (perhaps working in teams) compile a list of annotated (they
have to write 2-3 sentences telling what one can find at each link)
links to useful information on each plant. In the process of gathering
the links they will learn much about the plants.
3) While studying each group, bring in fossil evidence. My students
are fascinated to see some actual fossils of Calamites, Lepidodendron,
etc. when we study those groups. We also "extract" fossil plants from
coal balls and they are amazed that you can see cellular detail in ~350
million year old plants!
4) Culminate the plant diversity unit with a study of the mechanisms of
evolution. By the time you get to that unit, the students are bursting
with questions about how all the different plants arose. If you have
introduced the fossils, they already have the evidence of evolution not
to mention the evidence gleaned from their comparative morphology
studies.
In summary, morphological studies need to have a purpose if you expect
students to embrace the topic. We are fascinated by life cycles mainly
because we have the advantage of understanding them in a larger
context. That's why we have to teach them in a larger context.
*********************
David W. Kramer, Ph.D.
Asst. Prof. of Evolution, Ecology, and Organismal Biology
Ohio State University at Mansfield
1680 University Drive
Mansfield, OH 44906-1547
Phone: (419) 755-4344 FAX: (419) 755-4367
e-mail: kramer.8 at osu.edu
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