1. What is the largest and longest living type of tree?
DO NOW QUESTION
What is the largest and longest living type of tree?

2. Figure 31.0_3
Figure 31.0_3 Measuring the height of a coast redwood tree (Sequoia sempervirens) 2

3. Rings Wood rays Heartwood Sapwood Vascular cambium Secondary phloem
Figure 31.8B
Rings
Wood rays
Heartwood
Sapwood
Vascular cambium
Secondary phloem
Figure 31.8B Anatomy of a log
Bark
Cork cambium
Cork 3

4. Figure 31.8C
Figure 31.8C A giant sequoia that survived for 88 years with a tunnel cut through its heartwood. 4

5. SWBAT relate plant structures to their functions.
Objective
SWBAT relate plant structures to their functions.

6. People and Plants
Remember: Humans have engaged in agriculture for about 10,000 years.
Genetic manipulation of crop plants such as wheat began with cross-pollination of plants with desirable traits.
Today many crop plants are genetically modified using DNA technology.
Teaching Tips
The impact of the green revolution and the continued improvement of agricultural techniques may be little appreciated by your students. Yet as the text notes in Module 31.1, from 1940 to 1980, world wheat production doubled while the cost of production was cut in half. Consider sharing and discussing the importance of these developments as they relate to modern economies and the world’s population.
© 2012 Pearson Education, Inc. 6

7. Plant Organs: roots, stems, and leaves
Plants use a root system to
anchor the plant in the soil,
absorb and transport water and minerals, and
store food.
Root hairs: greatly increase the surface area for absorption.
Teaching Tips
Challenge your students to suggest circumstances when apical growth is more adaptive for a plant, and other situations in which branching would be more favorable.
© 2012 Pearson Education, Inc. 7

8. Plant Organs: roots, stems, and leaves
Plants use a shoot system to absorb the sun’s energy and carbon dioxide from the air.
A shoot system consists of stems, leaves, and reproduction adaptations.
Teaching Tips
Challenge your students to suggest circumstances when apical growth is more adaptive for a plant, and other situations in which branching would be more favorable.
© 2012 Pearson Education, Inc. 8

9. Plant Organs: roots, stems, and leaves
Plant root and shoot systems are interdependent (need each other).
Plant roots depend on shoots for carbohydrates produced via photosynthesis.
Plant shoots depend on roots for water and minerals.
Teaching Tips
Challenge your students to suggest circumstances when apical growth is more adaptive for a plant, and other situations in which branching would be more favorable.
© 2012 Pearson Education, Inc. 9

10. The modified root of a sugar beet plant
Figure 31.4A
The modified root of a sugar beet plant
(Carrots are also modified roots)
Figure 31.4A The modified root of a sugar beet plant 10

11. Modified Stems Stems may be modified as
Stems may be modified as
Tubers (potato) and rhizomes for storage
cactus stems for water storage and photosynthesis.
Teaching Tips
The modifications of the three plant organs described in Module 31.4 reveal the remodeling nature of evolution. As François Jacob noted, evolution works more like a tinkerer than an engineer. The common ancestry of eudicots is revealed by the diverse modifications of three basic plant organs derived from the shared ancestors. Your students’ appreciation of the enormous evidence in support of evolution will grow if you note such examples frequently throughout your course.
© 2012 Pearson Education, Inc. 11

12. Leaves may be modified for
Modified Leaves
Leaves may be modified for
climbing, such as a pea plant tendril
protection, such as a cactus spine.
Teaching Tips
The modifications of the three plant organs described in Module 31.4 reveal the remodeling nature of evolution. As François Jacob noted, evolution works more like a tinkerer than an engineer. The common ancestry of eudicots is revealed by the diverse modifications of three basic plant organs derived from the shared ancestors. Your students’ appreciation of the enormous evidence in support of evolution will grow if you note such examples frequently throughout your course.
© 2012 Pearson Education, Inc. 12

13. Modified Leaves – Floral Organs
1. Sepals enclose and protect a flower bud.
2. Petals attract pollinators (like bees).
3. Stamens are male reproductive structures.
4. Carpels are female reproductive structures.
Teaching Tips
1. The authors note in Module 31.9 that Modules 17.8 and 17.9 provide important background information on the sexual life cycle of a flowering plant. If these modules have not been addressed previously, consider adding them to the Chapter 31 assignment.
2. More students will recall that stamens are the male organs if they emphasize the word’s last syllable.
3. The four main parts of a flower, which are modified leaves, represent additional examples of evolutionary remodeling.
© 2012 Pearson Education, Inc. 13

14. Stigma Carpel Anther Style Stamen Ovary Filament Sepal Petal Ovule
Figure 31.9B
Stigma
Carpel
Anther
Style
Stamen
Ovary
Filament
Figure 31.9B The structure of a flower
Sepal
Petal
Ovule 14

15. The ovary develops into a fruit
Hormonal changes induced by fertilization trigger the ovary to develop into a fruit.
Fruits
house and protect seeds and
aid in their dispersal. (How?)
Student Misconceptions and Concerns
1. The distinction between fruits and vegetables is a frequent, if trivial, point of contention. Module specifically notes the structures and functions of fruits. To promote further understanding, consider discussing what the term vegetable means as well.
2. The development of the male and female gametophytes in flowers is often not as well understood by students who are more familiar with animals. A thorough review of the alternation-of-generations life cycle of plants is helpful before discussing the details of plant sexual reproduction.
Teaching Tips
Seed dispersal mechanisms are diverse and reflect specific adaptive strategies. The inventor of Velcro was inspired by the seed dispersal mechanisms of the common burdock plant.
Animation: Fruit Development
© 2012 Pearson Education, Inc. 15

16. Figure 31.12C
Maple fruits
Figure 31.12C A collection of fleshy (top) and dry (bottom) fruits 16

17. Three Tissues
Each plant organ (root, stem, or leaf) has three types of tissues.
1. Dermal tissue provides a protective outer covering. (similar to human epidermis)
2. Vascular tissue provides support and long-distance transport. (similar to cardiovascular system)
3. Ground tissue composes the bulk of the plant body.
Teaching Tips
1. Module 31.5 can be particularly problematic for students with limited backgrounds in plant biology. The basic structures and functions of tissues and subtypes of plants are introduced, and monocots and eudicots are compared. The terminology is extensive. Students may benefit most by creating their own mini-glossary for quick reference and study before, during, and after related lectures.
2. The functions of human epidermis have some analogues in plants. As in plants, our epidermis serves as a defense against physical damage and infectious organisms. In addition, oils on our skin help us retain water (and keep the epidermis flexible).
© 2012 Pearson Education, Inc. 17

18. Dermal Tissues & Water Maintenance
Cuticle: waxy outer layer
Tiny pores called stomata, which allow exchange of CO2 and O2
Each stoma is flanked by two guard cells that regulate the opening and closing of the stoma.
Teaching Tips
1. Module 31.5 can be particularly problematic for students with limited backgrounds in plant biology. The basic structures and functions of tissues and subtypes of plants are introduced, and monocots and eudicots are compared. The terminology is extensive. Students may benefit most by creating their own mini-glossary for quick reference and study before, during, and after related lectures.
2. The functions of human epidermis have some analogues in plants. As in plants, our epidermis serves as a defense against physical damage and infectious organisms. In addition, oils on our skin help us retain water (and keep the epidermis flexible).
© 2012 Pearson Education, Inc. 18

19. xylem tissue contains water-conducting cells
Vascular Plant Tissue
xylem tissue contains water-conducting cells
phloem tissue contains cells that transport sugars and other organic nutrients (plant food).
Teaching Tips
1. Module 31.5 can be particularly problematic for students with limited backgrounds in plant biology. The basic structures and functions of tissues and subtypes of plants are introduced, and monocots and eudicots are compared. The terminology is extensive. Students may benefit most by creating their own mini-glossary for quick reference and study before, during, and after related lectures.
2. The functions of human epidermis have some analogues in plants. As in plants, our epidermis serves as a defense against physical damage and infectious organisms. In addition, oils on our skin help us retain water (and keep the epidermis flexible).
© 2012 Pearson Education, Inc. 19

20. Eudicot leaf Cuticle Upper epidermis Xylem Vein Phloem Mesophyll
Figure 31.5_1
Eudicot leaf
Cuticle
Upper epidermis
Xylem
Vein
Phloem
Mesophyll
Guard cells
Lower epidermis
Stoma
Figure 31.5_1 The three tissue systems: in leaves (part 1)
Sheath
Key
Dermal tissue system
Ground tissue system
Vascular tissue system 20

21. Unique Plant Structures
Plant cells have three structures that distinguish them from animal cells:
Chloroplasts: the site of photosynthesis
Central Vacuole: containing fluid that helps maintain cell turgor (firmness)
Cellulose Cell Wall
Student Misconceptions and Concerns
Students may not understand turgor, although they encounter it in their lives. The shape of a water balloon is different from the shape of an uninflated balloon due to internal fluid pressure (turgor). A plant in need of water may have drooping leaves, a consequence of decreased turgor.
Teaching Tips
1. Cellulose is the most abundant organic compound on Earth. Students often find this fact worth remembering.
2. Students will remember the function of phloem more easily if you remind them that both phloem and food start with an “F” sound.
© 2012 Pearson Education, Inc. 21

22. Endoplasmic reticulum Secondary cell wall Middle lamella
Figure 31.6A
Chloroplast
Central vacuole
Cell walls
Nucleus
Primary cell wall
Endoplasmic reticulum
Secondary cell wall
Middle lamella
Mitochondrion
Golgi apparatus
Cell walls of adjoining cells
Ribosomes
Figure 31.6A The structure of a plant cell
Plasma membrane
Microtubules
Plasmodesmata
Pit
Plasma membrane 22