Student Misconceptions

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CHAPTER 38
ANGIOSPERM REPRODUCTION AND BIOTECHNOLOGY
I.
II.
Student misconceptions
1.
The angiosperm life cycle is very difficult for students to master. Students
find it hard to recognize that a tiny pollen grain and an embryo sac retained
within the ovule of the sporophyte really represent separate generations. It is
essential that students have a good understanding of the generalized
alternation of generations life cycle in plants before they attempt to
understand how this life cycle is modified in angiosperms.
2.
Students do not fully appreciate how fundamentally different plant life cycles
are from the more familiar animal life cycles. Most students think of the
embryo within the seed as the offspring of the sporophyte. They do not
recognize that a seed actually contains structures contributed by three distinct
generations of plants: the new sporophyte embryo, the remains of the female
gametophyte, and the seed coat produced by the embryo’s “grandparent.”
3.
Double fertilization is puzzling to many students. They may be confused by
the 3n condition of the endosperm, uncertain about how this triploid nucleus
is produced, and unclear about the significance of this event to angiosperm
reproduction.
4.
Many students mistakenly think that fruit is the product of syngamy,
containing genetic contributions from both parents. The issue is: Flower
produces fruit and fruit produces seed versus fruit develops only if seed is
formed.
Pre-test to identify student misconceptions prior to addressing the material
covered in Chapter 38
1.
Double fertilization:
a.
Is characteristic of seed plants
b.
Results in the fertilization of egg by sperm and polar nuclei by pollen
tube nucleus
c.
Produces a diploid sporophyte and a triploid endosperm
d.
Results from the fusion of the male and female gametophytes of
angiosperms
e.
Prevents the production of infertile pollen grains
2.
The gametophyte generation of an angiosperm is represented by:
a.
An anther
b.
A pollen grain
c.
An ovary
d.
An ovule
e.
An embryo sac
Student Misconceptions for Campbell/Reece Biology, 8th Edition, © Pearson Education, Inc.
38-1
III.
IV.
How can instructors address and correct the misconceptions that students
have about angiosperm reproduction and biotechnology?
1.
Clarify for students that fruits are mostly contributed by the sporophyte and
that the young sporophyte within the seed is the product of syngamy. Point
out that in order to get the same quality of fruit next season as this season,
the grower must use tissue derived from the sporophyte, such as a graft,
rather than planting the seed within the fruit.
2.
If students are familiar with the fern life cycle, pointing out the homologous
structures and stages of ferns and angiosperms may help them to understand
that the pollen grain and the embryo sac within the ovule represent adult
individuals of the gametophyte generation.
Post-test to identify whether students have corrected their misconceptions
1.
List the products and explain the significance of double fertilization in
angiosperms.
2.
“A seed contains structures contributed by three distinct generations of
plants.” Explain this statement.
Student Misconceptions for Campbell/Reece Biology, 8th Edition, © Pearson Education, Inc.
38-2
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