Week 09
Plants I
Reading Modules in Principles of Biology:
90. Plant Biodiversity and Humans
• Importance of Plant Biodiversity
• reats to Plant Biodiversity
91. Plants
• Plant Evolutionary Relationships
• Shared Derived Characteristics
92. Nonvascular Plants
• Characteristics of Nonvascular Plants
93. Seedless Vascular Plants
• Seedless Vascular Plant Evolution and Diversity
Reminder: e questions you encounter embedded within the reading or after it are there to give you feedback on
your understanding of the text. Answering those questions is optional (but encouraged), and your answers to those
questions are not visible to me or recorded by me.
This Week’s Schedule
Course Related
Other
SUN
MON
†
TUE
†
Lecture: Week 09 Reading Quiz (8:00–8:05)
Shared Derived Characteristics of Plants
Alternation of Generations
Lab: Diversity & Evolution of Photosynthetic Pigments
Prelab Activity due in MasteringBiology by 8 a.m.
WED
THU Lecture:
Nonvascular Plants
Seedless Vascular Plants
FRI
SAT Week 09 Homework due in MasteringBiology by 10 p.m.
†
†Indicates
an assignment due date.
You should bring your
biodiversity flashcards on urs.
Learning Outcomes for Week 09
Te
xt
b
Le ook
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La re
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Lecture art and a variety of other materials are available online. Log into Canvas, navigate to the
current week, and open the resource folder to see what is available.
Describe the various ways that humans have benefited from plant biodiversity.
✓
Explain how human activities threaten plant biodiversity.
✓
Differentiate green algae from aquatic plants in terms of their evolutionary
history.
✓ ✓ ✓
Identify the derived characteristics shared by members of the plant kingdom.
✓ ✓
Here is the list:
•
All plants demonstrate an alternation of generations, a type of life cycle
characterized by a diploid generation followed by a haploid generation.
•
All plants make spores by meiosis, using structures called sporangia.
•
All plants make gametes by mitosis, using structures called antheridia (which
make sperm) and archegonia (which make eggs).
•
All plants grow from dome-shaped caps of cells called apical meristems. Growth
from meristems is responsible for roots, shoots, leaves, etc.
Describe different types of evidence for the evolutionary relationship between
green algae and plants.
✓ ✓ ✓
Describe the characteristics of nonvascular plants.
✓ ✓ ✓
•
See the table at the end of this document.
Identify phases in the life cycles of nonvascular plants.
✓ ✓
Explain the ecological importance of mosses.
✓ ✓
•
On ursday, we’ll watch a video on the role of mosses in the carbon cycle.
Describe the characteristics of seedless vascular plants.
•
✓ ✓ ✓
See the table at the end of this document.
Identify phases in the life cycles of seedless vascular plants.
✓ ✓
Distinguish between seedless vascular plants and nonvascular plants based
on their characteristics.
✓
Note: is week’s lab will deal with algae and their relationship to plants. Next week’s lab will
address plant diversity.
✓
Terms, Titles, and People You Should Know
biodiversity
biofuel
alternation of generations
apical meristem
antheridium vs. archegonium
charophyte
gametophyte
phragmoplast
sporangium
sporophyte
vascular tissue
xylem vs. phloem
lignin
megaphylls vs. microphylls
Phylogenetic Groups You Should Know (with pertinent examples)
is table is intended to serve as a study guide following what we cover in class.
Grouping
Shared Derived Characters
Representative
Members
Nonvascular Plants
•
Gametophyte-dominant life cycle
•
No truly specialized vascular tissue, which means:
Phylum Hepaticophyta
liverworts
(sometimes called
bryophytes, although
only the mosses belong
to Phylum Bryophyta)
they cannot conduct water (or other materials)
throughout their bodies;
they cannot grow very tall; and
they do not have true roots (instead, they possess
rhizoids that anchor them to the soil).
Seedless Vascular
Plants
•
Bodies lack adaptations that prevent drying out, and
therefore they are restricted to moist habitats:
•
Sporophyte-dominant life cycle
•
Presence of vascular tissue (xylem and phloem)
•
Leaves for photosynthesis (microphylls)
•
Cell walls contain lignin, a structural molecule that
strengthens the vascular tissue; responsible for these
plants being able to grow off of the ground.
•
“Advanced” seedless vascular plants also:
Phylum
Anthocerophyta
hornworts
Phylum Bryophyta
true mosses
Phylum Lycophyta
club mosses
spike mosses
quillworts
Phylum Pterophyta
true ferns
whisk ferns*
horsetails*
Have larger leaves (megaphylls) with veins; and
Are heterosporous: able to produce either male or
female spores, resulting in male or female
gametophytes. (More “primitive” seedless vascular
plants and all nonvascular plants are homosporous;
they only make one type of spore that produces a
bisexual gametophyte.)
*older texts sometimes
refer these organisms as
fern allies.
Life Cycle Diagrams of Representative Nonvascular and Seedless Vascular Plants: