EXPLORING LIFE
EXERCISE 5:
SPORE-PRODUCING
TRACHEOPHYTES
Exercise 5: Spore-Producing Tracheophytes
Workbook Contents
Corresponding Section on CD
Vocabulary
Key Concepts
Introduction
1. Introduction
General Characteristics
Bryophytes vs. Tracheophytes
Stem Cross Sections
Vascular Tissue
Arrangements of Vascular Tissue
Basic Tissue Systems
Life Cycles
Tracheophyte Groups
2. General Characteristics
2A. Conducting Tissues
2B. Steles
2B. Steles
2B. Steles
2C. Basic Tissue Systems
2D. Life Cycle
Division Psilotophyta
3. Psilotophyta
Division Lycophyta
4. Lycophyta
4A. Introduction
4B. Lycopodium
4C. Selaginella
4D. Isoetes
Family Lycopodiaceae – Genus Lycopodium
Family Lycopodiaceae – Genus Selaginella
Family Isoetaceae – Genus Isoetes
Division Sphenophyta
5. Sphenophyta
Division Pterophyta
6. Pterophyta
Evolutionary Trends
7. Evolutionary Relationships
Summary & Review
Additional Vocabulary
Vocabulary
Adventitious - Arising from an abnormal location such as a root arising from stem tissue
Angiosperms - Flowering plants. These plants bear seeds in fruits. Apples and beans are common examples.
Antheridium - Male reproductive structure which produces sperm
Archegonium - A female reproductive structure which produces an egg.
Corm - An underground storage stem that gives rise to the aerial portion of the plant. Usually the stem is in the
upright position.
Cuticle - Waxy substances on the surfaces of the aerial portions of most plants. Cuticles reduce evaporation.
Dermal tissue - One of the three basic tissue systems of plants, i.e. the skin of herbaceous plants and young
woody plants.
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Dichotomous branching - Branching into two equal parts
Eustele - A siphonostele (i.e., a stele with a pith) in which the vascular tissues are arranged in discrete strands or
bundles
Ground tissue - All tissues other than dermal and vascular. These tissues are normally primary tissues.
Parenchyma is a common example.
Gymnosperms - Naked-seeded plants. These plants produce seeds but the seeds are not found in fruits. Pine
trees are familiar examples.
Heterosporous - Producing both microspores and megaspores. All seed plants are heterosporous.
Homosporous - Producing only one type of spore, as lycopodium does
Indusium - A covering over the sorus on the leaves of some ferns
Megaphyll - A large leaf whose vascular trace is associated with a leaf gap. Megaphylls are believed to have
evolved from systems of branches. The leaves of angiosperms and gymnosperms are megaphylls.
Microphyll - A small leaf that has a single vascular trace and is not associated with leaf gaps in the stem.
Microphylls are believed to have evolved as outgrowths of the epidermis that subsequently
became vascularized. Lycopodium produces microphylls.
Parenchyma - Refers to both a cell and tissue type. Parenchyma cells have a thin wall, retain their nucleus, and
are the major ground tissue of most plants. Parenchyma tissue is composed of parenchyma cells.
Phloem - One of two vascular tissues. Phloem primarily conducts sugars, hormones and dissolved nutrients.
Phyllotaxis - The arrangement of leaves along the stem
Pith - Ground tissue in the center of a root or stem as in clover stems and corn roots. Normally, the pith is
composed of parenchyma, though some pith have sclerenchyma.
Prothallial cell - Cells found in male gametophytes that do not participate in reproduction nor produce cells that
do participate in reproduction. Prothallial cells are believed to be vestiges of vegetative cells
found in the gametophytes of primitive plants.
Protostele - A stele without a pith. Protosteles are believed to be the most primitive type of stele. Psilotum has a
protostele.
Rhizome - An underground stem often used in asexual reproduction and storage. Rhizomes typically grow more
or less horizontally.
Sieve cells - Conducting cells in the phloem of some plants. Sieve cells are characterized by having tapering
end walls and sieve areas on their side walls. Conifers and many seedless vascular plants produce
sieve cells.
Siphonostele - A stele with a pith as in a clover stem or corn root. Ferns and all seed plants produce
siphonosteles.
Sporangium - A structure that produces spores. In all plants, spore production is part of the sexual life cycle.
Sporophyll - A leaf that produces a sporangium
Stele - The center of a stem or root, interior to the ground tissue
Stomata - An opening in the epidermis that is surrounded by guard cells and permits gas exchange. The stomata
properly consist of the hole (stoma) and the surrounding guard cells.
Strobolus - A series of modified leaves that bear sporangia, i.e. a cone. Lycopods, horsetails, and gymnosperms
produce stroboli.
Trabeculae - Elongated cells in the center of horsetail stems that support the stele
Tracheids - Water-conducting cells in the xylem that have closed end-walls and pits along their radial side
walls. Most tracheophytes produce tracheids.
Tracheophyte - Plants that produce vascular tissues in which some cells have both a primary and secondary cell
wall
Venter - The portion of an archegonium that contains the egg
Xylem - The vascular tissue that conducts water up tracheophyte bodies. Some xylem cells have both a primary
and a secondary cell wall.
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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
structural and life cycle characteristics of the spore-producing
tracheophytes so that you will be able to distinguish:
How these plants are classified
1. What structural and life cycle characteristics distinguish the sporeproducing tracheophytes from other groups of plants?
2. What structural and life cycle characteristics distinguish each division
of spore-producing tracheophytes from the others?
The evolutionary trends demonstrated in these plants
3. What are the evolutionary trends in development in the structural and
life cycle characteristics of the tracheophytes?
The first five 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. Italicized
subheadings denote a series of slides within a larger section, while bold
subheadings correspond to buttons given for each Division and Family.
The subsequent four 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, which is also available on-screen as
part of the exercise module.
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SPORE-PRODUCING TRACHEOPHYTES
Introduction
1. Write the common name of each plant and the Division to which each belongs:
____________________
____________________
____________________
____________________
____________________
____________________
____________________
____________________
General Characteristics
Bryophytes vs. Tracheophytes
2. Draw a line from picture to the cell type, then draw a line from the cell type to the appropriate cell wall
structure and then to the group in which it is found:
Cell Type
Cell Wall Structure
Group
hydroid
primary &
secondary
Bryophytes
leptoid
tracheid
primary
only
vessel
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Tracheophytes
KEY CONCEPTS
Stem Cross Sections
3. Label the stem cross sections using these symbols and identify the genus/group to which they belong:
cortex (co)
cuticle (cu)
dermal (d)
endodermis (en)
epidermis (ep)
ground (g)
pericycle (pe)
phloem (ph)
pith (pi)
vascular (v)
xylem (x)
Genus:
Genus:
Genus:
Genus:
Group:
Group:
Group:
Group:
Genus:
Genus:
Genus:
Group:
Group:
Group:
Vascular Tissue
4. Describe the difference between the xylem and phloem in terms of the cell wall structure:
Arrangements of Vascular Tissue
5. Define stele: ____________________________________________________________________________
6. Describe the differences between the three stele types – protostele, siphonostele and eustele – and give an
example of each:
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SPORE-PRODUCING TRACHEOPHYTES
Basic Tissue Systems
7. Identify each tissue system (dermal, ground, vascular) and the structures found in each:
8. What differentiates plant organs from one another? ______________________________________________
What differentiates animal organs from one another? ____________________________________________
Life Cycles
9. Which phase is dominant in the life cycle of tracheophytes – the sporophyte or the gametophyte? (circle one)
10. Label the life cycle diagram below with the following terms (some may be used more than once):
diploid
fertilization
gametes gametophyte haploid
meiosis
mitosis spores zygote
sporophyte
Tracheophyte Groups
11. What are the two major groups of tracheophytes and what is the difference between them?
Division Psilotophyta
12. What is the name of the representative for this group?
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KEY CONCEPTS
Stem Cross Section
13. Describe and label the stem cross section; include xylem, phloem, sieve cells, tracheids, primary cell wall,
secondary cell wall, end walls, dead, alive
Sporophyte
14. What type of “leaf” structure is this? Why is this not a true leaf?
15. Circle the term or phrase on each line that best describes the structural or life cycle features of this Division:
Gametophyte
a. gametophyte location – above ground or below ground
b. gametophyte associations – associated with a fungus or not
c. sperm – need water to swim to through to egg or do not need water
Reproductive Structures d. sporosity – homosporous or heterosporous
Rhizome
e. roots – no roots, adventitious roots arising from rhizomes or true roots
Other Representatives
16. To what climates is this group restricted?
Division Lycophyta
17. Is this group restricted to certain climates, as the Psilotophyta were?
Family Lycopodiaceae – Genus Lycopodium
Roots
18. Does this group have no roots, adventitious roots arising from rhizomes or true roots? (circle one)
Leaves
19. Does this group have scales, microphylls or megaphylls? (circle one)
20. What are the major differences between microphylls and megaphylls in terms of:
a. vascularization:
b. evolution:
c. association with steles:
d. examples of plants:
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SPORE-PRODUCING TRACHEOPHYTES
21. What are sporophylls?
22. Circle the term or phrase on each line that best describes the structural or life cycle features of this family:
Stem Cross Section
a. stele type – protostele, siphonostele or eustele
Sporophyte B
b. sporangia - sori, strobili, or no special structures
Reproductive Structures c. sporosity – homosporous or heterosporous
Gametophyte
d. gametophyte location – above ground or below ground
e. gametophyte associations – associated with a fungus or not
f. maturity time – years, months, or weeks for the gametophyte to mature
Family Lycopodiaceae – Genus Selaginella
23. Circle the term or phrase on each line that best describes the structural or life cycle features of this family:
Sporophyte
a. sporangia - sori, strobili, or no special structures
b. sporosity – homosporous or heterosporous
Gametophyte
c. reproductive needs – sperm need water to swim through or do not
d. maturity time – years, months, or weeks for the gametophyte to mature
Family Isoetaceae – Genus Isoetes
24. How many genera in this family?
What are their habitat requirements?
Roots
25. What root structure does this family possess in addition to adventitious roots?
Stem Cross Section
26. What special type of tissue is found in this family?
Label the tissue types on this cross section:
Leaves
27. Is this family homosporous or heterosporous? (circle one)
Division Sphenophyta
28. How many genera in this family?
Sporophyte
29. What is special about the stem?
30. Circle the term or phrase on each line that best describes the structural or life cycle features of this Division:
Roots
a. roots – no roots, adventitious roots arising from rhizomes or true roots
Leaves
b. leaf type – scales, microphylls or megaphylls
Stem Cross Section
c. stems – stem hollow or not hollow
Reproductive Structures d. sporangia - sori, strobili, or no special structures
e. sporosity – homosporous or heterosporous
Gametophyte
f. maturity time – years, months, or weeks for the gametophyte to mature
g. reproductive needs – sperm need water to swim through or do not
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KEY CONCEPTS
Division Pterophyta
Sporophyte
31. Is this group more diverse or less diverse than the previously studied groups? (circle one)
32. Among what structures is this diversity apparent?
Roots
32. Does this division at any time in its life cycle have true roots?
When?
Leaves
33. Do ferns have microphylls or megaphylls? (circle one)
34. Label the various frond types:
35. Circle the term or phrase on each line that best describes the structural or life cycle features of this Division
Stem Cross Section
a. stele type – protostele, siphonostele or eustele
Reproductive Structures b. sporangial associations – with leaves or not with leaves
c. sporangia - sori, strobili, or no special structures
d. sporosity – homosporous or heterosporous
(water ferns only)
e. sporosity – homosporous or heterosporous
Gametophyte (most)
f. gametophyte location – above ground or below ground
g. gametophyte associations - associated with a fungus or not
h. reproductive needs – sperm need water to swim through or do not
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SPORE-PRODUCING TRACHEOPHYTES
Evolutionary Trends
Use the following symbols: Psilotum (P), Lycopodium (L), Selaginella (S), Equisetum (E), Ferns (F),
water ferns (W) and seed-producing tracheophytes (T)
36. Which groups possess protosteles?
Siphonosteles?
Which stele type is the most primitive?
37. What is the difference between tracheids and vessels?
Which groups possess tracheids?
Vessels?
38. Which leaf type(s) are associated with protosteles?
Siphonosteles?
Eusteles?
39. Among which groups are sporangia associated with leaves?
Not associated with leaves?
Heterosporous?
Which groups are homosporous?
40. What are the three characteristics shared by most all spore-producing tracheophytes?
a.
b.
c.
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Eusteles?
SUMMARY AND REVIEW
Structural Details
tracheids
vessels
protostele
siphonostele
eustele
scales
microphylls
megaphylls
sporangia not associated with leaves
sporangia associated with leaves
no specialized reproductive leaf structures
sporophylls
strobili
sori
no roots
adventitious roots arising from rhizome
true roots
stem not hollow
stem hollow
Life Cycle Details
homosporous
heterosporous
water needed for sperm to reach egg
water not needed for sperm to reach egg
gametophyte matures in years
gametophyte matures in months
gametophyte matures in weeks
gametophyte matures in days
gametophyte subterranean w/symbiotic fungus
gametophyte above ground and photosynthetic
Diversity
few genera or species
many genera or species
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Seed-producing
tracheophytes
Pterophyta/
water ferns
Pterophyta/
ferns
Sphenophyta/
Equisetum
Lycophyta/
Isoetes
Lycophyta/
Selaginella
Lycophyta/
Lycopodium
Psilotophyta/
Psilotum
Divisions/
Genera
Refer to the questions you answered on the previous pages. Mark the appropriate boxes with an “X” to denote
that the Division/Genus possesses that trait.
SPORE-PRODUCING TRACHEOPHYTES
Referring to the completed summary table, answer the following questions:
How these plants are classified
1. What structural features do most tracheophytes share that bryophytes do not?
a.
b.
c.
2. What life cycle characteristic do all tracheophytes share?
3. What structural features do most spore-producing tracheophytes share?
a.
b.
4. What life cycle characteristic do most spore-producing tracheophytes share?
5. What characteristics do Psilotophyta and Lycophyta share that other spore-producing tracheophytes do not?
6. What do the Psilotophyta lack that all other tracheophytes posses?
7. What characteristic(s) could you use to distinguish between the Sphenophyta and all Pterophyta?
8. Develop a dichotomous key to distinguish among these groups: bryophytes and tracheophytes; sporeproducing and seed-producing tracheophytes; Psilotophyta, Lycophyta, Sphenophyta and Pterophyta
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KEY CONCEPTS – SUMMARY AND REVIEW
Referring to the completed summary table, answer the following questions:
Evolutionary Trends
9. In each group, list the characteristics of the tracheophytes in order from most primitive to most derived. The
first one has been done for you as an example:
a. roots: no roots to adventitious roots to true roots
b. steles:
to
to
c. “leaf” type:
to
to
d. sporangial associations:
e. sporosity:
to
to
f. water needs of sperm:
g. gametophyte maturity time:
to
to
to
to
10. Describe, using complete sentences, the evolutionary trends in structure and life cycle that have allowed
tracheophytes to come to dominate the land over bryophytes.
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ADDITIONAL VOCABULARY
Fill in the answers, then transfer the marked letters to the blanks at the bottom of the page:
A row of large cells with thick cell walls found across
the top of Pterophyta sporangia
__ __ __ __ __ __ __
Hollow openings in Sphenophyta stems
__ __ __ __ __ __ __ canals
Unrolling of a Pterophyta leaf
__ __ __ __ __ __ __ __ __ vernation
A short, fleshy underground stem found in Isoetes
__ __ __ __
Pattern the produces two fairly equal branches; found
among the Psilotophyta
__ __ __ __ __ __ __ __ __ __ __ branching
Structure that cover and protect developing Pterophyta sporangia __ __ __ __ __ __ __ __
Structure found at the base of Selaginella sporangia
but not that of Lycopodium
__ __ __ __ __ __
Growing points that give rise to lateral branches in
Sphenophyta
__ __ __ __
The final subdivision of a Pterophyta frond
__ __ __ __ __ __ __
Lycophyta gametophyte consisting of a single vegetative cell
__ __ __ __ __ __ __ __ __ __ cell
Main axis of a Pterophyta leaf
__ __ __ __ __ __
Sporangial clusters on the underside of Pterophyta fronds
__ __ __ __
Special tissue that nurtures developing Pterophyta spores
__ __ __ __ __ __ __
Structures of cortical cells that support the stele in the
center of Selaginella stems
__ __ __ __ __ __ __ __ __ __
Arrangement where many leaves originate at the same
node of a Sphenophyta
whorled __ __ __ __ __ __ __ __ __ __ __
The vocabulary words used to complete this puzzle are specific to the:
__ __ __ __ __-__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
1 2 3 4 5 2 4 3 6 7 8 9 10 11 12 4 13 8 14 5 3 2 14 15 12 5 1
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