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Notes to Instructors
What is the overall focus of activities associated with Chapters 35 to 51?
Activities from earlier chapters and from the chapters on the diversity of organisms
allowed students to develop an understanding of these topics:
• The events that occurred in the evolution of multicellular organisms in general
and of plants and animals in particular
The activities in Chapters 35–51, which cover the units “Plant Form and Function” and
“Animal Form and Function” in Campbell Biology, 9th edition, are designed with these
objectives:
• These activities build on the understanding of how the structure of each system is
related to (or in a sense, determines) its function.
Chapter 35 Plant Structure, Growth, and Development
What is the focus of this activity?
In this activity, students are asked to compare the basic form of monocots and dicots
(both herbaceous and woody) to learn key similarities and differences in their structure
and function.
What is this particular activity designed to do?
Activity 35.1 How does plant structure differ among monocots, herbaceous dicots,
and woody dicots?
The questions in this activity are designed to help students review and understand the
240 Notes to Instructors
Answers
Activity 35.1 How does plant structure differ among
monocots, herbaceous dicots, and woody dicots?
The chart on the next page shows a drawing of a generic plant. The arrows indicate
various plant parts or organs. In the columns to the right of the plant, draw cross sections
of the plant at the points indicated by the arrows.
Activity 35.1 241
Generic plant
Column 1
Cross sections
if plant is a monocot
Column 2
Cross sections if plant is
a herbaceous dicot
Column 3
Cross sections if plant is
a woody dicot
a
b
Apical meristem
Leaf dorsal
dorsal
phloem
Petiole
phloem
xylem
xylem
Same as Column I
Same as Column I
phloem
phloem
xylem
Same as column 1
Same as column 2
Same as column 1
2nd pholem
carbium
Use the information in your drawings to answer the questions on the next pages.
1. In Column I, connect the cross sections of the monocot by drawing a line (color 1)
from the water transport tissue in one section to the water transport tissue in the next,
and so on. Draw another line (color 2) to connect the food transport tissue from one
section to the next. Do the same for the herbaceous and the woody dicot cross sections.
How do the positions of these tissues change from one cross section to the next?
As students make these connections, they should see:
• In leaves organized horizontally, the xylem lies dorsal to or on top of the
phloem within each vascular bundle.
2. Use the information in the cross sections to fill in the chart below. Note: A
distinguishing feature is one that is found in only the given type of organism. For
example, a distinguishing feature of mammals is the presence of hair: Hair is a
characteristic of all mammals and is not found in any other animals.
Activity 35.1 243
(Continued on next page)
Distinguishing feature(s) of
Leaf Stem Root
Apical meristem
shoot vs. root
Monocot Vascular
traces (veins)
in the leaf are
arranged in
Vascular
bundles are
scattered
throughout the
Vascular
bundles form
a ringlike
pattern around
The apical meristem
of the root is covered
by a protective root
cap. In addition to the
intercalary meristems.
244 Activity 35.1
Herbaceous
dicot
Vascular
traces (veins)
in the leaf are
arranged in a
netlike
pattern.
Vascular
bundles are
arranged in a
ring between
a thin outer
cortex layer
There is no
central pith.
Xylem forms
a crosslike
pattern in the
center of the
As in monocots, the
apical meristems of the
roots are generally
protected by a root cap.
There is generally no
protective tissue layer
Woody dicot Vascular
traces (veins)
in the leaf are
arranged in a
netlike
pattern.
Vascular
cambium is
continuous
and produces
secondary
xylem to the
A ring of
vascular
cambium
forms
between the
central xylem
As in monocots, the
apical meristems of the
roots are generally
protected by a root cap.
There is generally no
protective tissue layer
3. If cross sections were not available, what other characteristics of the plants as a
whole could you use to determine whether each was a monocot, a herbaceous dicot,
or a woody dicot?
Monocot leaves have parallel veins (vascular bundles); dicot leaves have netlike
4. A cartoon shows a man going to sleep in a hammock suspended between two
relatively short trees. The second frame of the cartoon shows the man waking
20 years later and finding his hammock 15 feet higher off the ground. Critique this
drawing in terms of what you know about the growth pattern of trees.
If the tree is a dicot, then its growth in height occurs by the addition of cells at the
Activity 35.1 245
35.1 Test Your Understanding
How is the general morphology of the various organs of a plant correlated with the
function(s) of those organs? For example, why are leaves generally thin and flat? What
structural advantage is provided by stems having their vascular tissue arranged in a ring
near the periphery of the stem? What characteristics of roots and root growth dictate that
the vascular tissue be more centrally located?
Thin flat leaves have very high surface-area-to-volume ratios. As a result, they maximize
surface area, enabling them to expose more photosynthetic cells to sunlight. Their large
