Chapter 17 Lecture Outline
A Gentle Giant
Plants are unique organisms.
Basic characteristics of the plant kingdom (Module 17.1).
Examining the giant sequoia,
helps underscore the unique
capabilities and adaptations of plants. The tree known as General Sherman is the largest
individual plant on Earth: 84 m tall, 10 m in diameter at the base, first branch at 40 m,
weighing about 1,400 tons, and alive for about 2,500 years (chapter-opening photos).
Humans depend on plants for a variety of needs (e.g., lumber, fabric, paper, and food), and
many other organisms depend on them for nutrition and shelter.
Despite the importance of plants, on a worldwide basis, slightly more
photosynthesis is carried out by photosynthetic protists (algae) and bacteria of aquatic
Giant sequoias are gymnosperms (naked seeds; Modules 17.7 and 17.8). Because
angiosperms (covered seeds; Modules 17.9–17.13) make up 90% of the world’s plant
species, they are the focus of this chapter.
Module 17.3 discusses the basic differences between gymnosperms and
Talking About Science: Plant scientist Natasha Raikhel studies the
plant as a
model biological system.
Dr. Natasha Raikhel is the Distinguished Professor of Plant Cell Biology at the University of
California, Riverside. She recently received an award from the American Society of Cell
Biology for her work on the mustard seed plant,
Raikhel uses the mustard seed plant to study biological systems and the structure-function
relationship in plants. Raikhel is a leader in the field of plant cell biology, and she also loves to
share her enthusiasm for plants with her students (Figure 31.1A).
I. Plant Structure and Function
The two major groups of angiosperms are the monocots and the dicots.
include orchids, bamboos, palms, lilies, and grasses (including most of the
agricultural, grain-producing plants). They are distinguished by having one seed leaf
but also usually have parallel-veined leaves, scattered vascular bundles in stems,
floral parts in multiples of three, and fibrous root systems (Figure 31.2).
Most angiosperms are
Dicots include most shrubs and trees (except conifers) and many
herbaceous plants, including many food plants and plants domesticated for their fibers. They are
distinguished by having two cotyledons but also usually have net-veined leaves, vascular
bundles in a ring in stems, floral parts in multiples of four or five, and taproot systems.