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Chapter #22 - Plants with Seeds
I. 22-1, Seed Plants - The Spermopsida
Objectives:
*1. Describe the advantages and disadvantages of life on land for plants.
*2. Name some adaptations that plants have made to life on land.
*3. Discuss the functions of roots, stems, and leaves
*4. Compare the structure and function of xylem and phloem.
*5. Discuss the Reproductive structures of plant
*1-A. Advantages to life on land for plants
1. Plenty of sunlight for plants to carry out food making - Photosynthesis.
2. CO2 and O2 for photosynthesis and respiration.
*1-B. Disadvantages to life on land for plants
1. Plants can only get H2O and nutrients from the soil in which they live.
2. Evaporation of water from the plant due to the dryness of the air.
3. Leaves must be held toward the sun for photosynthesis to take place.
4. Reproduction must occur without the aid of H2O.
*2-C. Adaptations of plants to survive on land
1. Occurred over a long period of time
2. Those plants that had the best adaptations for land, reproduced and survived.
3. Vascular system - to move H2O, minerals, nutrients, and food throughout the plant.
4. Evolved roots, stems and leaves to carry out the life functions of the plants (grow tall - Fig.#22-3).
5. Evolved seeds.
*3-D. Function of Roots (Fig.#22-2)
1. Anchor the plant to the ground.
2. Hold the plant up so that it faces the sun.
3. Absorbs H2O, and nutrients from the ground
*3-E. Function of Stems
1. A stem holds it's leaves so they face the sun.
2. A stem fights for sunlight with other stems from other plants.
3. Stems are tough to support it's weight (wind, rain, snow, and ice)
*3-F. Function of Leaves
1. Organ of the plant that absorbs sunlight for photosynthesis.
2. Have a large, flat surface for absorbing sunlight (chlorophyll able to spread out)
3. Because plants with leaves could absorb more sunlight, they could produce more food, and be stronger and healthier than other types of photosynthetic organisms.
4. Cuticle - Wax coating to protect this broad, flat structure from losing H2O.
5. Special openings to allow O2, CO2, and H2O to enter and leave the leaf.
*4-G. Vascular Tissue (tissue for movement of material throughout the plant)
1. Why vascular tissue
a. The distance water and nutrients had to travel between the leaves and roots increased (some as tall as 100m)
b. Variation, chance and natural selection, selected plants that had an advanced circulatory system.
2. Xylem - Vascular tissue responsible for moving H2O and nutrients.
a. Moves H2O from roots to leaves.
b. Has thick cell walls, which gives the plant strength.
c. Are dead when they function in water circulation.
3. Phloem - Vascular tissue responsible for moving materials produced during photosynthesis.
a. Move glucose from the leaves and stems to the roots.
b. Can move the glucose in any direction (plant stores food in the roots, but all cells need the food to carry out it's life functions).
c. Cells are alive, and contain cytoplasm (used to help move the glucose)
*5-H. Reproductive Structures of Plants on Land
1. Flowers and Cones - Structures on land plants where pollination occurs, and seeds develop.
2. Pollination - Fertilization of an egg by the pollen grain.
a. Occurs by: wind, water, insects, birds, animals.
3. Pollen grain - Male gamete of a plant (sperm).
4. Egg - Female gamete of a plant.
5. Seed - Structure that protects the zygote (fertilized egg).
6. Embryo - The small plant in which the fertilized egg grow into while still in the seed.
7. Seed Coat - Structure of a seed that protects it until conditions are favorable for growth (weeks, months, or even years).
Homework: Section Review Questions, P#470 of Text.
Teacher's Resource Book: Plants Designed for Life on Land, P#475-476.
II. 22-2, Evolution of Seed Plants
Objectives:
*1. Describe the evolution of Seed Plants
*2. List the characteristics of Gymnosperms
*3. List the characteristics of angiosperms
*4. List the characteristics of monocots
*5. List the characteristics of dicots
*1-A. Evolution of Seed Plants
1. Each time a group of plants evolved a useful new adaptation, that adaptation gave rise to new species.
2. Adaptations gave the plants abilities to live in areas that other plants could not live.
3. Adaptations gave the new plants an edge at living in a given area, that plant grew and reproduced, other plants died off.
4. The earth was constantly changing over time (continents moved, mountain ranges sprung up).
5. 300-400 million years ago, the earth was wetter, ferns and mosses covered earth (need water to reproduce with spores)
6. Earth became dryer, ferns and mosses died off, seed plants took over the earth.
7. First seed-bearing plants looked like ferns, but all have died off.
*2-B. Characteristics of Gymnosperms
1. Oldest of all seed plants
2. Male cones produce pollen (carried by wind to eggs)
3. Female cones produce eggs, and is where seed develops.
4. Seeds protected by a seed coat and are not covered by the cone (sit naked=gymno, sperm=seed)
5. 3 classes of Gymnosperms
a. Cycadae - Palmlike plants (fig.#22-7)
1. only 9 types still live
2. found in Mexico, Florida, Asia, Africa and Australia
b. Ginkoae
1. only one species left - Ginkgo biloba
2. tolerates pollution well
c. Coniferae
1. Conifers - evergreen
a. pines, spruce, fir, cedar, sequoias, redwoods and yews
2. Found in North America, China, Europe, and Australia
3. Can live to 4000 years
4. 100m tall
5. Adaptations
a. Leaves in the form of needles
b. Constantly losing needles, usually not at once (larches and bald cypress lose needles)
*3-C. Characteristics of Angiosperms
1. Angiosperms - Flowering plants
2. Fruit - Protective wall that the seeds develop in.
a. apples, oranges, beans, pea pods, pumpkins, tomatoes, and even eggplants
3. Over 250,000 species which are found all over the world.
4. Pollination usually by insects or animals, attracted by flower or scent of the flower.
*4-5. Two Sub-Classes
a. Monocots
1. Corn, wheat, lilies, orchids, grass
2. Veins of leaves are parallel
3. Flowers in threes, or groups of three
4. Have scattered vascular bundles (phloem and xylem)
5. Most stems do not grow thicker
6. Cotyledons - seed leaves, only one.
b. Dicots
1. Roses, maple trees, strawberries, daisies
2. Branching veins in leaves
3. Flower parts in fours or fives
4. Arranged vascular bundles
5. Stems grow thicker (most trees)
Laboratory Manual: Comparing Monocots and Dicots, P#273-276
Homework: Study Guide; Evolution of Seed Plants, P#211-213
III. 22-3, Coevolution of Flowering Plants and Animals
Objectives:
*1. Discuss the process and importance of plant-animal coevolution.
*2. Describe the methods of pollination in seed plants.
*3. Discuss the methods of seed dispersal
*1-A. Coevolution - The process where two organisms evolve structures and behaviors in response to changes in each other over time (ex. angiosperms and its pollinators)
1. Flowering plants evolved about 125 million years ago.
2. Insects and birds evolved before the plants, and mammals about the same time as plants (important, plants could only evolve if the insects, birds and mammals were already on earth)
*2-B. Flower Pollination
1. Pollination is needed for flowering plants to reproduce.
2. Wind (few angiosperms pollinated this way)
a. willow trees, ragweed, and grasses
b. tiny, simple flowers, without much fragrance
c. wind blows pollen to flowers, very inefficient.
3. Vector Pollination - Pollination by insects, birds, or mammals (how most angiosperms are pollinated)
a. plants become pollinated.
b. plants provide pollinators food (pollen or nectar, which is 25% glucose)
c. benefits both plant and pollinator
d. very efficient means of transporting pollen from one plant to another.
e. specific pollinators and their plants occurred accidentally at first, and then evolved.
4. Bees as pollinators (fig.#22-16)
a. bee finds pollen (food), memorizes shape, color and odor of flower.
b. bee looks for more flowers of the same type.
c. carries, by mistake, pollen from one plant to another.
d. bee see ultraviolet, blue and yellow light best, flowers it pollinates will be those colors.
e. bees pollinate by landing on the flower, so flower must have landing area for bee.
5. Night-flying Moths as pollinators
a. colors not important (can't see without light)
b. excellent sense of smell, so flowers give off floral fragrances.
c. moths feed while flying, with a long tongue
d. nector is usually found deep in the flower
6. Birds as pollinators
a. birds have good sight and see orange and red best
b. poor sense of smell
c. so, red flowers without fragrance are pollinated.
Video – Plant Pollination
C. Seed Dispersal (to scatter seeds)
1. Reduces competition (for sunlight, water and nutrients), between parent and offspring
2. Spread plant to new environments.
3. Barbs, hook to animal (fig.#22-19)
4. Fruits with bright colors, good taste, and nutrients (fig.#22-19)
a. fruit digested, seeds with tough seed coat dispersed with waste (fertilizer)
b. unripe fruits have undeveloped seeds
c. taste bitter, because of chemicals produced by plant (stop animals from eating fruit)
d. green color, hides developing fruit in leaves
e. ripe fruit, injected with sweet nectar and has bright colors which attract animals (red = ripe)
5. Wind (fig.#22-18)
Homework: Teacher Resource book; Flower Pollination and Seed Dispersal, P#477-479.
Study Guide; Coevolution of Flowering Plants and Animals, P#214-216.