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EXPLORING LIFE
EXERCISE 6:
SEED PLANTS
Exercise 6: Seed Plants
Workbook Contents
Corresponding Section on CD
Vocabulary
Key Concepts
Introduction
1. Introduction
Seeds
2. Seeds
Differences Between Gymnosperms and Angiosperms
3. Difference Between Gymnosperms and
Angiosperms
Pine Vegetative Body
4. Pine Vegetative Body
Pine Reproduction
5. Pine Reproduction
The Cycads, Ginkgo and the Gnetophyta
6. The Cycads
7. Gingko
8. The Gnetophyta
Division Anthophyta: The Flowering Plants
9. Division Anthophyta: The Flowering
Plants
9A. Introduction
9B. Flowers
9C. Fruits
Introduction
Flowers
Fruits
Summary & Review
Vocabulary
Accessory fruit - A fleshy fruit containing ovarian and non-ovarian tissue, e.g. an apple
Achene - A simple dry indehiscent fruit derived from an inferior ovary in which the seed occupies most of the
volume of the fruit and the seed coat does not adhere to the pericarp
Aggregate fruit - A fruit derived from many pistils in the same flower
Angiosperms - Flowering plants
Anther - That part of a stamen that produces pollen
Anthophyta - The division of flowering plants
Antipodals - Haploid cells of the female gametophyte of angiosperms found at the end of the gametophyte
opposite the micropyle
Berry - A simple fleshy fruit with multiple seeds and derived from more than one carpel, e.g., a grape
Bract - A modified leaf usually smaller than normal vegetative leaves
Calyx - The whorl of sepals
Carpel - The smallest segment of a pistil that encloses ovules
Cleistogamy - A breeding system in which a flower is pollinated by its own pollen before the flower opens
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Coleoptile - A sheath enclosing the shoot of grasses in the seed. This sheath penetrates the soil in advance
of the shoot.
Coleorhiza - The sheath that encloses the root of grasses
Corolla - The whorl of petals
Cotyledon - Seed leaf
Dicotyledons - One of the two major groups of angiosperms characterized by having two cotyledons
Dioecious - Species composed of unisexual individuals, i.e., staminate and pistillate plants
Drupe - A simple fleshy fruit that has a thin ectocarp, a fleshy mesocarp, and a hard stony endocarp and is
usually a single seed, e.g., a peach
Ectocarp - The outer layer of the pericarp. The differentiation of the pericarp into three layers is common in
fleshy fruits but not dry fruits.
Endocarp - The inner layer of the pericarp of a fleshy fruit
Endosperm - A distinctive nutritive tissue found only in angiosperms. The endosperm results from the fusion of
a sperm with the polar nuclei and consequently usually has an odd ploidy number.
Epicotyl - The upper portion of the embryo from which the shoot is derived
Epigynous - Refers to a flower that appears to arise from a point above the ovary
Filament - The stalk supporting an anther
Follicle - A simple dry dehiscent fruit that splits only along one axis
Funinculus - The stalk supporting an angiosperm ovule
Gymnosperms - Naked seeded plants
Hypocotyl - That portion of the embryo below the cotyledons
Hypogynous - Refers to a flower in which the ovary is above where the other floral whorls attach to the stem
Integuments - One of two pairs of leaves that surround the nucellus
Legume - Dehiscent fruit formed from one carpel that splits along two axes
Mesocarp - The middle portion of a fleshy pericarp, i.e., between the ecto- and endocarps
Micropyle - The opening between the integuments of seed plants
Monocotyledons - One of the two major groups of angiosperms characterized by the presence of one seed leaf
Monoecious - An individual that produces both pistillate and staminate flowers
Nucellus - Megasporangium of seed plants
Nut - A dry indehiscent fruit derived from a compound ovary and having a hard pericarp
Ovule - An ovule is composed of the integuments, nucellus and a female gametophyte of seed plants. A seed
develops from a fertilized ovule.
Ovuliferous scale - The modified leaf that bears the ovules of some gymnosperms
Pepo - A modified berry having a hard rind for an ectoderm, e.g., a watermelon
Pericarp - The fruit wall. The pericarp is derived from the ovary wall.
Pistil - A single carpel or a fused group of carpels that function as a unit
Polar nuclei - Two or more haploid nuclei in the angiosperm embryo sac that migrate from either pole to the
center of the sac where they are fertilized by a sperm. The resulting polyploid tissue becomes the
endosperm.
Pollen grains - The immature male gametophytes of seed plants
Protandry - A breeding system characterized by the stamens maturing before the pistils
Prothallial cell - A cell in the male gametophytes of seed plants that does not directly participate in reproduction
Protogyny - A breeding system characterized by the pistils maturing prior to the stamens
Radicle - The portion of the embryo that becomes the root
Seed - A mature fertilized ovule
Sepal - A modified leaf found in the lowest whorl of a flower
Stamen - The male or pollen producing structure of flowers
Synergids - A pair of haploid cells on either side of the egg in an angiosperm ovule
Tapetum - A nutritive tissue found in the microsporangium of angiosperm anthers
Tube cell - The haploid cell in the male gametophyte of seed plants that directs the growth of the pollen tube.
In the Anthophyta, it is only a haploid nucleus, not a separate cell.
Whorl - Three or more leaves or modified leaves that occur at the same node
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KEY CONCEPTS
This section of the workbook is set up to help you note important
information relating to the key concepts of this exercise and then organize
and summarize the information in order to develop a synthesis and prepare
for a review. As you complete this exercise, you will focus on the
characteristics of various plant tissue types so that you will be able to
distinguish:
Seeds
1. What is a seed?
2. How does a seed develop?
Gymnosperms and Angiosperms
3. What are the similarities/differences between these two groups?
4. What are some specific structures of gymnosperms? angiosperms?
5. How do gymnosperms reproduce?
6. What are some of the different groups of gymnosperms? How are they
alike? How are they different?
7. What are the reproductive structures of angiosperms? How do they
function?
The first eleven pages are questions that can be answered by following the
progression of slides and paying careful attention to the information, both
visual and audio. These questions should be read in advance of each
section so that you can be better prepared to answer them by knowing
what you are looking for. The underlined subheadings correspond to the
sections of the exercise as outlined in the main menu.
The subsequent pages are designed to help you summarize and synthesize
the pertinent information to answer the questions posed above. These are
followed by a review quiz.
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SEED PLANTS
Introduction
1. Match the plant groups with their common names and seed characteristics:
gymnosperm
flowering plants
seeds naked upon cone scale
angiosperm
naked seed plants
seeds found inside fruits
Seeds
2. In nonseed-producing tracheophytes, the gametophyte / sporophyte is the dominant stage and the
gametophyte / sporophyte is independent of the dominant stage. Air / Animals / Water is/are
needed for fertilization to occur.
3. Seeds plants, like non-seed plants, are heterosporous / homosporous, forming both megaspores
and microspores / only megaspores / only microspores, which develop into male and female
gametophytes, respectively.
4. Label each of the following phrases as a characteristic of non-seed (N) or seed-producing (S) plants:
both megaspores and microspores fall to ground, where gametophytes develop
female gametophyte is retained in tissue of sporophyte, up in the air
male gametophyte reduced to pollen grain, moved by wind, water or animal
sperm swim from one plant to another; fertilization tied to availability of free water
internal fertilization; sperm do not need to swim and so some do not have flagella
no internal fertilization; sperm need to swim and so need to have flagella
Differences Between Gymnosperms and Angiosperms
5. What are the traits that all seed plants share? List at least three:
6. The most consistent difference between the two groups involves the development of the
7. Label the following diagram. Be sure to use the terms: egg, synergid, antipodals, polar nuclei, nucellus
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.
KEY CONCEPTS
8. In the development of the male gametophyte, how many sperm are formed?
What do each of these sperm do?
What do the fertilized polar nuclei develop into?
9. All / Most angiosperms produce an endosperm; they all also have double / single fertilization.
On the other hand, all / most / no / only one genus/genera of gymnosperms has double
fertilization, and only some / no endosperm is developed.
10. Mark each of the following statements (A) for angiosperms and (G) for gymnosperms:
nucellus surrounded by two pairs of integuments
produce tracheids in their xylem
nucellus surrounded by one pair of integuments
produce vessels in their xylem
all members of this group woody; none are herbaceous
produce cones
members of this group can be woody or herbaceous
produce true flowers
Pine Vegetative Body
. Some are deciduous /
11. The first group of gymnosperms in this exercise is the
evergreen and keep their leaves year-round, while others are deciduous / evergreen and lose their
leaves.
12. Circle which of the following conifer plant organs is woody:
cones
leaves
roots
stems
13. Label the following on the diagrams below: tracheid, pit, resin duct. Why are the cell walls of the tracheids
so thick?
Are these cells alive or dead ? What is their function?
14. Describe the function of the resin duct. How has this system helped our understanding of prehistoric life?
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SEED PLANTS
15. Label the following diagrams with the terms: xylem, phloem, sieve area. The conducting cells of the
phloem have only a primary / primary and secondary cell wall(s). When mature, sieve cells
have cytoplasm / have no cytoplasm and have a nucleus / lack a nucleus. A neighboring cell
called a(an) albuminous cell / companion cell regulates the sieve cell’s cytoplasm.
16. Label the diagram with these terms: xylem, phloem,
vascular cambium, bark. When the cambium divides,
the daughter cell may remain in line and become
cambium / phloem / xylem, get pushed inside
and become cambium / phloem / xylem, or get
pushed outside and become cambium / phloem /
xylem. This action is called primary / secondary
growth, which all / most gymnosperms exhibit.
The epidermis / periderm of the young plant will
be lost and will be replaced by epidermis /
periderm. Which two tissues form the bark of the
pine tree?
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KEY CONCEPTS
17. What are pine leaves called?
18. Connect the following terms to its place on the diagram and its definition (you may want to wait until the
last segment of this exercise, when most of the structures are labeled all at once; then repeat as needed).
cuticle
gas exchange
hypodermis
helps reduce loss of water from stomata
resin duct
composed of wax to help retain water
endodermis
second skin inside epidermis
phloem
photosynthetic tissue
xylem
third or inner skin
transfer tissues
help transfers to and from vascular system
mesophyll
water-conducting vascular tissue
stomata
sugar-conducting vascular tissue
chamber
exudes substance to deter and trap insects
Pine Reproduction
19. Label each of the following statements as belonging to male (M) or female (F) pine cones:
microsporangiate; usually smaller
borne on lower branches
megasporangiate; usually larger
borne on upper branches
20. How and why are male and female cones spatially separated?
21. Label the diagram and describe the arrangement and
number of structures in the male cone. Be sure to
include the terms microsporophyll,
microsporangium, mother cells
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SEED PLANTS
22. Number the following steps (from 1 to 11) in the order that they occur:
body cell undergoes mitosis and forms 2 sperm
microspore mother cell undergoes meiosis
each microspore undergoes 2 mitotic divisions
one sperm fertilizes egg
four microspores are formed
pollen grain produces two wings
generative cell divides to form stalk and body
cell
pollination occurs
sperm carried to egg by pollen tube
male gametophyte is formed
tube cell starts to produce pollen tube
23. Connect these terms to the diagram:
ovuliferous scale
bract
ovule
funiculus
nucellus
24. Number the following steps (from 1 to 18) in the order that they occur:
cell walls form in female gametophyte
pollen grain is captured
four cells in layer furthest from micropyle
develop into separate embryos
pollen tube grows
pollen tube reaches archegonium
four megaspores formed in a line
remaining megaspore divides by mitosis
layer below four embryos elongate and push
embryos into female gametophyte
single egg formed by each archegonium
sperm discharged into egg cytoplasm
megagametophyte (with 2000 nuclei)
formed
surviving embryo develops four layers of cells
three megaspores farthest from micropyle
break down
megaspore undergoes meiosis
micropyle exudes pollen droplet
two embryos form from fertilized ovules
one sperm fertilizes egg; other
disintegrates
two to three archegonia develop
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KEY CONCEPTS
25. Match the following terms to the diagram:
cotyledons
apical meristems
hypocotyl root axis
root apical meristem
female gametophyte
seed coat
The Cycads, Ginkgo and the Gnetophyta
form endosperm
do not form endosperm
double fertilization
single fertilization
produce flowers
produce stroboli
sperm do not have flagella
sperm have flagella
deciduous
leaves with parallel veins
insect pollinated
wind pollinated
dioecious
have vessels
have tracheids
wide range/habitats
restricted range/habitats
26. Mark an “X” in the boxes that correspond to characteristics found within each group.
Example
organism(s)
Conifers
Cycads
Gingko
Gnetales
Angiosperms
Division Anthophyta: The Flowering Plants
Introduction
27. True or False: The flowering plants are the largest group of plants ever.
True or False: The flowering plants are the least diverse group of plants ever.
True or False: The flowering plants are the most successful group of plants ever.
True or False: The flowering plants group has a narrow range of sizes.
True or False: All flowering plants have single fertilization, an endosperm, flowers, fruits and seeds.
True or False: All flowering plants possess tracheids in their xylem and sieve tubes in their phloem.
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SEED PLANTS
Flowers
Flower Structure
28. Match the whorl number with the whorl name and structures found in that whorl:
Whorl Name
Structures
1
calyx
anthers and filaments
2
corolla
carpels and ovules
3
pistils
petals
4
stamen
sepals
Whorl Number
29. Label the following structures on the flower diagram: sepal, calyx, petal, corolla, perianth, stamen, filament,
anther, pistil. You may need to repeat this section of the CD several times to complete this question.
Flowers – Male Reproductive Structures
30. Match the following structures to this anther cross-section:
locule
mother cells
tapetum
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KEY CONCEPTS
31. Number the following steps (1 to 11) in the order in which they occur:
anther walls split open
coating is deposited on the pollen grains
generative cell and tube nucleus are
formed
generative cell divides by mitosis
haploid microspores are produced
microspores divide by mitosis
mother cells undergo meiosis
pollen grain lands on receptive surface
pollen is dispersed
tube nucleus produces a pollen tube
two non-flagellated sperm are produced
Flowers – Female Reproductive Structures
You will have to view this section several times to completely answer the questions for this section.
32. Label the structures on the ovule:
outer integument
antipodals
inner integument
polar nuclei
nucellus
synergids
funiculus
egg
embryo sac
micropyle
33. How many pair of integuments do gymnosperms have?
How many do angiosperms have?
34. Number the following steps (1 to 10) in the order in which they occur:
one sperm fertilizes polar nuclei;
endosperm forms
endosperm breaks down to nourish embryo
female gametophyte (embryo sac) forms
pollen tube penetrates embryo sac through
the micropyle
four megaspores are formed
megaspore continues to divide
remaining megaspore divides
megaspore mother cell divides
sperm are deposited in pollen tube
one sperm fertilizes egg; zygote forms
three megaspores disintegrate
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SEED PLANTS
Flowers – Structure Modifications
35. Label the following structures on the flower diagram:
carpel, stigma, style, ovary, ovules.
36. Once the ovules are fertilized and become fruit / seeds, the ovary will become the fruit / seeds.
37. Match each ovary type with the correct flower type and placement of the perianth in relation to the ovary:
Ovary Type
Flower Type
Placement of Perianth
superior
epigynous
perianth fusion to stem above ovary
inferior
hypogynous
perianth fusion to stem around ovary
perigynous
perianth fusion to stem below ovary
38. Wind pollinated flowers typically are missing one or both ovary / perianth parts. Why?
39. True or False: Wind pollinated flowers are usually devoid of any attractive device.
40. Match the flower type with its description (one description matches with two of the flower types):
Flower Type
Description
complete
flower has stamens or pistils, but not both
imperfect
flower has all four whorls
incomplete
flower is lacking one or more whorls
perfect
flower has stamens and pistils
unisexual
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KEY CONCEPTS
Flowers – Inflorescences
41. What are the branches that bear flowers called?
Flowers – Pollination
42. What has affected the size, color and shape of flowers?
43. Most flowering plant species are pollinated by animals / wind, and most plants use
as an attractant. Label the following colors by the animals that are attracted to them: hummingbirds (H),
bees (B), moths and bats (MB).
blue
orange
red
ultraviolet
violet
white
yellow
44. List at least three of the other attractants plants use:
45. What do animals get from this relationship?
What do plants get?
46. Animal / Wind pollinated plants produce nectar and pollen while animal / wind pollinated plants
produce only nectar / pollen.
47. True or False: When a flower’s own pollen lands on its stigma, this self-pollination leads to selffertilization and is called cleistogamy.
True or False: When a plant’s own pollen lands on the stigma of one of its flowers, this is called
dichogamy.
48. Why to plants usually want to avoid self-pollination and self-fertilization?
49. Mark the following statements (D) for dioecious or (M) for monoecious:
male & female flowers on separate plants
flowers are perfect
male and female flowers on same plants
examples include box elder, aspen and willow
flowers are imperfect
examples include cucumbers and watermelon
50. If stamens and pistils on the same flowers are not functional at the same time, it is called
.
These flowers are imperfect / perfect. If the stamens mature before the pistils, it is called protandry
/ protogyny, while if the pistils mature before the stamens it is called protandry / protogyny.
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SEED PLANTS
51. What mechanisms allows self-pollination but not self-fertilization?
Fruits
52. What is the function(s) of the fruit?
What structure is modified to form the fruit?
multiple seeds per fruit
one seed per fruit
fleshy endocarp
hard endocarp
dry mesocarp
fleshy mesocarp
thick ectocarp (rind)
thin ectocarp
fruit is from the stem
fruit from multiple ovaries
fruit from single ovary
fruit from many flowers
Fleshy Fruit Type
simple
drupe
accessory
berry
pepo
aggregate
of drupe
of accessory
multiple
fruit from one flower
53. Mark an “X” in the boxes that correspond to characteristics found within each group.
example fruits
do not split (indehiscent)
split in different ways
split along one axis
split along two axes
dehiscent
fruit from multiple ovaries
Dry Fruit Type
legume
follicle
capsule
achene
caryopsis
fruit from single ovary
54. Mark an “X” in the boxes that correspond to characteristics found within each group.
example fruits
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KEY CONCEPTS
55. Label the following characteristics (D) for dicot and (M) for monocot.
one cotyledon (scutellum)
true root replaced by adventitious root
two cotyledons (seed leaves)
seed surrounded by seed coat
epicotyl forms stem and leaves
little endosperm left in seed
embryo forms radicle, coleoptile and
coleorhiza
much endosperm left in seed
floral parts in multiples of three
embryo forms true root
floral parts in multiples of 4 or 5
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SEED PLANTS
1. What are the major differences between non-seed and seed-producing plants? Be sure to examine their
structure, reproduction and life cycle and include such terms as sporophyte, gametophyte, pollen grains,
sperm, internal fertilization, and flagella in your discussion.
2. In what ways are all seed-producing plants the same?
3. In what ways are gymnosperms and angiosperms different?
4. What characteristics link all gymnosperms?
What characteristics link most gymnosperms?
What characteristics are unique to the conifers?
What characteristics are unique to the cycads?
What characteristics are unique to the ginkgos?
What characteristics are unique to the gnetales?
5. What characteristics link all angiosperms?
6. What characteristic of fertilization has enabled seed-producing plants to colonize dry land?
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SUMMARY AND REVIEW
7.
Circle the flowers that are complete. Draw a box around the flowers that are incomplete. Draw a solid
headed arrow (
) to the flowers that are perfect. Draw a non-solid headed arrow (
) to the flowers
that are imperfect.
8. Can flowers be imperfect and complete?
Explain:
Can flowers be perfect and incomplete?
Explain:
9. Describe some of the ways flowers are pollinated and the characteristics that each type of flower has:
10. Describe some of the ways in which flowers avoid self-pollination and self-fertilization:
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