Biology & Life Sciences Chapter 35 Homework The Apical Meristem The Root Covered Protective

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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

Apical meristem

Leaf dorsal

dorsal

phloem

Petiole

phloem

xylem

Same as Column I

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