conifer reproductive cycle -...
TRANSCRIPT
T28 Laboratory Manual
Copyright ©
Glencoe/M
cGraw
-Hill, a division of T
he McG
raw-H
ill Com
panies, Inc.
Lab 23
Imm
atur
ese
ed c
one
Scal
e
Ovul
e
Polle
n co
ne
Po
lle
n t
ub
e
Tetra
d m
icros
pore
s
Meg
aspo
re
Eggs
(w
ithin
meg
agam
etop
hyte
s)
Polle
n(m
icrog
amet
ophy
tes)
Zygo
te
Scal
e
Pine
seed
(with
win
g)
Polli
natio
n an
dFe
rtiliz
atio
n
Mei
osis
Mei
osis
Adul
tsp
orop
hyte Yo
ung
spor
ophy
teM
atur
ese
ed c
one
Sper
m n
ucle
i
Polle
n
Coni
fer R
epro
duct
ive
Cycl
e
How to Use the Student Models, continued
Laboratory Manual T29
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yrig
ht ©
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ncoe
/McG
raw
-Hill
, a d
ivis
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of T
he M
cGra
w-H
ill C
ompa
nies
, Inc
.
Lab 23
Clus
ters
of
spor
angi
a
Spor
angi
um
Prot
hallu
s (m
atur
e ga
met
ophy
te)
Mat
ure
spor
ophy
te
Youn
gsp
orop
hyte
Anth
erid
ium
Fron
d
Rhizo
me
Root
sAr
cheg
oniu
m
Egg
Zygo
te
Fertilization
Spor
es
Root
s
Soil
Prot
hallu
s
Meiosis
Mot
ilesp
erm
cel
ls
Egg
cell
Fern
Rep
rodu
ctiv
e Cy
cle
How to Use the Student Models, continued
T30 Laboratory Manual
Copyright ©
Glencoe/M
cGraw
-Hill, a division of T
he McG
raw-H
ill Com
panies, Inc.
Lab 23Meiosis
Fertilization
Spor
e ca
psul
e(s
pora
ngiu
m)
Zygo
te
Gam
etop
hyte
s
Anth
erid
ia
Mal
eFe
mal
e
Mos
s Re
prod
uctiv
e Cy
cle
Mat
ure
spor
ophy
te
Youn
gsp
orop
hyte
Mot
ilesp
erm
Egg
Germ
inat
ing
spor
e
Spor
es
Arch
egon
ia
How to Use the Student Models, continued
194 TEACHER GUIDE AND ANSWERS Laboratory Manual
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Glencoe/M
cGraw
-Hill, a division of The M
cGraw
-Hill C
ompanies, Inc.
Teacher Guide and Answers, continued
Analyze and Conclude 1. These structures are hyphae. They are the fungal
cells. All mushrooms have them. The student’s ability to remove them from the stalk in each sample will depend on the types of mushroom.
2. The hyphae hold the mushrooms in place and help them absorb food or water. Above-level learners may note that fungi secrete enzymes from the hyphae then absorb the digested nutrients. One of the things that distinguishes fungi from other heterotrophs is that they are absorptive.
3. Answers will vary. Students might be able to estimate how many spores are on each radiating line and then multiply by the number of lines in their print. Students should recognize that mushrooms usually grow in moist, warm, and dark places. Spores that do not immediately germinate will remain dormant until the proper growth conditions are met, or they will die.
4. Just as the air in the balloon scattered the cotton balls far away from the balloon, air currents can carry spores far from the mushrooms. Because so many spores are produced, the chances that the spores will land in a favorable environment are great.
5. Answers will vary. Some students might mention that they find a visual display easier to understand.
6. Answers will vary. Students might have found it difficult to identify the parts of a mushroom, or to count the spores; or their balloon might not have spread the cotton balls.
7. The wind would make the model more realistic, spreading the spores even farther from the source. This would also affect the pattern of dispersal.
Inquiry Extensions 1. Common poisonous mushrooms include the fly
argaic and the death cap. 2. Answers will vary. Students who research this
topic will discover general methods for active spore release: the bursting cell, ballistospore discharge, and the catapult or “rounding off.” Students might recognize that, after release, spores can be transported by mammals, birds, insects, leaves, and water. Above-level learners might discover that some spores can survive passage through an animal’s gut, to be dispersed in dung.
Lab 23 • ClassicHow do ferns, mosses, and conifers reproduce?
Objectives• Examine samples of ferns, mosses, and conifers.• Compare characteristics of seeds, spores, and
pollen in each.• Infer how these characteristics have made survival
of each plant possible.
Process Skillsanalyze, examine, compare and contrast, infer
Time Allotment45–60 minutes (45 minutes for lab, an additional 15 minutes for discussion)
Materials fern fronds (with sori) forceps moss sample (with paper towels sporophytes) dropperpine cones (male and water female) petri dishdiagrams of the magnifying lens or life cycles of stereomicroscope, ferns, mosses, and if available conifers colored pencilsscalpel
Preparation• Some students might be allergic to pollen.
Advise those students to take proper precautions (e.g., face masks) before starting the lab.
• Distribute diagrams of the life cycles of mosses, ferns, and conifers from How to Use the Student Models, pp. T24–T31, or some other source. If possible, use color photocopies, posters, colored prints, or artwork.
• If possible, have students examine live plants instead of samples. Going outside to see real examples is preferable.
Laboratory Manual TEACHER GUIDE AND ANSWERS 195
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yrig
ht ©
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ncoe
/McG
raw
-Hill
, a d
ivis
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he M
cGra
w-H
ill C
ompa
nies
, Inc
.Teacher Guide and Answers, continued
Teaching the Lab• Ask students to think about what they know about
ferns, mosses, and conifers and the environ ment they grow in before starting the lab. This will help students focus their attention on the differences between these plants.
• Circulate around the room to head off any problems or answer any questions that arise.
Data and Observations 1. Accept all reasonable diagrams. For the fern,
students should draw the underside of the pinna and show the attached sporangia. If moss are in the fruiting stage, students should note the fruiting structure, including the filament, and the sporangium. Male and female pine cones might be attached to the same branch and found in clusters. Generally speaking, the male cones are soft and fleshy, while the female cones are the “classic” hard-finned cone (depending on the stage at which it was harvested).
Female pine cone
Male pine cone
Sporangium
Filament (or stalk)
Gametophyte
Moss fruiting body
Sporophythe
2. Accept all reasonable diagrams. Drawings of the fern spore should show sorus, and if possible, the spores within. Student drawings of the microscopic view of the moss could show the antheridial head, sperm in antheridium, or the ovule in the archegonium. Student drawings of the seeds from a conifer should show the seed body and, depending on the species, any winglike structure used to aid dispersal.
196 TEACHER GUIDE AND ANSWERS Laboratory Manual
Copyright ©
Glencoe/M
cGraw
-Hill, a division of The M
cGraw
-Hill C
ompanies, Inc.
Teacher Guide and Answers, continued
Analyze and Conclude 1. Students should notice the black spots on the
underside of the frond and identify these as spore capsules.
2. Students should notice a lack of seeds in the moss plant. They should see a green, fuzzy plant with tiny rootlike structures called rhizomes.
3. The pine cone might have some leaves, or needles, attached to it. The students might notice the difference between male and female cones. The female cone might have scales with two ovules.
4. The pine tree is a gymnosperm, and it goes through the steps of pollination, fertilization, seed development, and dispersal. The ferns and mosses lack seeds, so they have a different life cycle, which includes the need for water so the sperm can swim to the egg.
5. The fern capsule will develop into a structure with both male and female reproductive structures. The young plant will develop after pollination occurs, whereas the conifer seed is already fertilized. They both contain what is needed for the future generation. The moss sporophyte is similar to the fern capsule in that it contains spores which will be released under the right conditions.
6. Inability to prepare a fine enough section, or lack of discernible structures in the specimens are possible sources of error.
7. Conifers need sandy soil and deep water sources. Ferns and mosses need a moist environment to spread the sperm cells.
Inquiry Extensions 1. Accept all reasonable designs. Students should
make note of the mechanisms (osmosis and diffusion) that allow water and nutrients to reach all portions of the moss.
2. These plants are essential for biodiversity. They serve as producers within the food chain and provide habitats for other creatures. Students might also remark on the plants’ value to humans—for instance, mosses are often used to hold moisture in the soil in gardens or houseplants, or as an emergency bandage for cuts in the skin. Pines are widely used for building materials and furniture. Ferns are considered attractive foliage for houseplants and in floral arrangements.
Lab 24 • Design Your OwnDo plants sweat?
Objectives• Form a hypothesis about how transpiration
is affected by a change in an environmental condition.
• Design an experiment to test the impact of this environmental condition.
Process Skillsform hypotheses, control variables
Time Allotment 45 minutes to set up10 minutes per day for several days
Materialselectric fan small plastic bags food coloring (not the zippered kind)live plant tiespipette petroleum jelly scissors watersmall beaker
Possible HypothesisIf plants are exposed to an environment with more direct sunlight, then the rate of transpiration will increase.
Possible Procedure 1. Choose a location in the classroom that receives
direct sunlight for a majority of the day. If such a location is not available, set up a small desk lamp to simulate the sun.
2. Cover two leaves of the plant with plastic bags. Gently tie the plastic bags around the stem of the leaf.
3. Ensure that one of the leaves is in the direct sunlight.
4. The other leaf covered by the bag needs to be shaded from the sunlight. Cover this leaf and bag with a small lunch bag.
5. During the next few days, check on the plant. Any water that is leaving the leaf though transpiration will collect in the plastic bags as condensation.