24 Study Guide
Growth, Development, and Reproduction
Plants reproduce, develop, and grow in response to cues from the environment such as light, temperature, and moisture. Hormones manufactured by the plant regulate the plant's responses to change.
24.1 Reproduction in Flowering Plants
Flowers are reproductive organs that are composed of four different kinds of specialized leaves: sepals, petals, stamens, and carpels.
The process of fertilization in angiosperms is distinct from that found in other plants. Two fertilization events take place—one produces the zygote and the other a tissue, called endosperm, within the seed.
Vegetative reproduction is the formation of new individuals by mitosis. It does not require gametes, flowers, or fertilization.
24.2 Fruits and Seeds
As angiosperm seeds mature, ovary walls thicken to form a fruit that encloses the developing seeds.
Seeds contained in fleshy, nutritious fruits are usually dispersed by animals.
Seeds dispersed by wind or water are typically contained in lightweight fruits that allow them to be carried in the air or in buoyant fruits that allow them to float on the surface of the water.
Environmental factors such as temperature and moisture can cause a seed to end dormancy and germinate.
24.3 Plant Hormones
Plant hormones serve as signals that control development of cells, tissues, and organs. They also coordinate responses to the environment.
The opposing effects of plant hormones contribute to the balance necessary for homeostasis.
Plants respond to environmental stimuli such as light, gravity, and touch.
Photoperiodism is a major factor in the timing of seasonal activities such as flowering and growth.
As cold weather approaches, deciduous plants turn off photosynthetic pathways, transport materials from leaves to roots, and seal off leaves.
24.4 Plants and Humans
Worldwide, most people depend on a few crop plants for the bulk of their food supply.
Plants produce the raw materials for our homes and clothes, and some of our most powerful and effective medicines.
green revolution (717)
Think Visually Make a concept map that includes the major concepts for the four lessons of this chapter. A sample map for Lesson 24.1 is shown here.
Table of Contents
- Formulas and Equations
- Applying Formulas and Equations
- Mean, Median, and Mode
- Estimation
- Using Measurements in Calculations
- Effects of Measurement Errors
- Accuracy
- Precision
- Comparing Accuracy and Precision
- Significant Figures
- Calculating With Significant Figures
- Scientific Notation
- Calculating With Scientific Notation
- Dimensional Analysis
- Applying Dimensional Analysis