Lesson Notes for Chapter 22
Introduction to plants
22-1 Introduction to plants
Vocabulary:
Objectives:
22.1.1: Explain what a plant is
22.1.2: Describe what a plant needs to survive
Notes to accompany slides:
PPT 1: Science starter (optional) – possible answers... paper, Kleenex, furniture, clothing (cotton), desk,
make-up, rope,
insulation, towels, soaps & shampoos, toothpaste... and many, many products contain
corn (adhesives, cosmetics, crayons, chalk, plastics, disposable diapers, dyes, firecrackers...), etc.
PPT 2: (answers on slide 3) You may wish to ask students for answers first.
examples: plants are multicellular, eukaryotes, they get food by making it, using energy from the sun
they have chloroplasts in their cells and cell walls, which animal cells do not have...
PPT 3: List in notes
PPT 4 & 5: Go over what plants need. See text p. 552
PPT 6: Read first 2 paragraphs on p. 553. Note that plants today have the same reproductive cycle as green
algae. Originally all found in water, they began to colonize the land. What problems would a plant have,
living on land?
Read p. 554, 1st paragraph
PPT 7: Interpret cladogram (may be first introduction to cladograms)
PPT 8: When flowering plants first evolved, they were so successful, they covered the earth very quickly.
NOTE NUMBER OF SPECIES (May be surprised at the diversity of mosses, ferns, and
gymnosperms)
PPT 9: 4 groups of plants are pictured. Focus on the 3 characteristics that determine each group.
Go Quickly through bryophytes. We just want to let students know they exist,
and understand the difference between vascular and non-vascular plants.
Homework: 22-1 w.s.
22-2 Bryophytes
(brief)
Vocabulary: bryophyte
Objectives:
22.2.2: Identify three groups of bryophytes
FOCUS: Bryophytes are non-vascular, must live in damp area
PPT 10: Description of bryophytes (page556-557); Take notes on characteristics
PPT 11: Most common examples. Recognize these groups of as Bryophytes, but I do not plan on assessing
anything about individual groups. No notes needed for specific group characteristics.
Mosses most common – they grow near water. Well adapted to wet habitats and poor nutrient soils.
They don’t have roots, but instead they have “rhizoids”, long thin cells that anchor the plant into the
ground, helping to absorb water and minerals from the soil. Mosses are the most abundant plant in the
polar regions and a main food source for caribou.
Liverworts – look like a flat leaf that is attached to the ground. It gets its name because some have
leaves shaped like a liver. Liverworts reproduce asexually. Small multicellular spheres that contain
haploid cells are washed off the parent plant and begin a new plant. The gametes are found in the
structure that looks like a little umbrella.
Hornworts are similar to Liverworts in their reproduction. They are found where the soil stays damp
year-round. The gametes are found in the structure that looks like a tiny green horns.
Bryophytes cannon reproduce without water!
Human uses: some mosses, when dried, absorb many times their own weight, acting as a natural
sponge. The dead remains form thick deposits called “peat”. Peat is used as a fuel, and also mixed
into soil for gardens to hold water, and to lower the pH for plants like azaleas (like acid soil)
PPT 12-13: Diagrams of moss – structure and reproduction. Left in for optional use. No need to go into
detail. May wish to mention the gametophyte (N) as a review from meiosis chapter, but go through
very quickly.
Last slide: Short description of fungi. Note differences between fungi and plants.
PPT 14: May wish to note differences between plants and fungi. Some students may think fungus looks like
plants sometimes, and lichens can be mistaken for moss. Note Fungi groups: mushrooms (many are
poisonous) reproduce by spores and can end up landing in a circle... Sac fungi (morels, not
mushrooms!), shelf fungi (parasitic), molds, and lichens (symbiotic relationship between a fungus
and either green alga or a cyanobacterium
No Homework
22-3 Seedless Vascular Plants (Ask Amy for a spring, slide 17)
Vocabulary: vascular tissue, xylem, phloem, lignin, root, vein, leaf, stem, rhizome, frond, sporophyte,
gametophyte,
PPT 15: Start of Vascular plants. Ferns are the earliest examples we have of vascular tissue.
Ask students how they can grow so tall?
PPT 16: Parts of vascular tissue... xylem and phloem. Xylem is one way. Water can only go up!
Students write definitions. (Analogy... blood pressure takes blood in legs back to heart, valves in
veins keep blood from dropping back down.)
READ First paragraph under “Evolution of Vascular tissue, page 560
READ KEY – Both forms of vascular tissue- Xylem and Phloem, can move fluids throughout the
plant body, even against the force of gravity
PPT 17: Lignin makes cell walls rigid, allowing plants to grow very tall. Notice the structure of the plant
stem. Ask students to look at the lignin. What does it look like? (spring, coil, slinky). Note that lignin
gives the plant structure, but still allows it to move! Show students spring and demonstrate how
strong it is, but can move. Engineers put large springs, similar to this small one, inside concrete in
Earthquake prone areas like southern California and Japan.
(Bottom right-hand corner micrograph of stem: LEFT “Phloem sieve tube element with sieve plate;
RIGHT “Protoxylum with annual thickening & Protoxylerm with helical to reticulate thickening”
PPT 18: Review groups of seedless vascular plants.
Club moss, or Lycopodia: a primitive vascular plant. These plants were dominant during the
Carboniferous period, when they attained the size of trees, and contributed to the coal deposits in North
America. They are considered more advanced than true mosses because they are vascular (specialized fluidconducting tissues). Club mosses are usually creeping or epiphytic (Epiphytes grow on other plants and take
nutrients from them... like mistletoe). Live in moist places, especially in tropical and subtropical forests.
They reproduce by means of spores, and have scale-like leaves. Also called ground pine or creeping cedar.
Horsetails: Only living genus left is Equisetum (Note “equestrian” and “horse”tail, also called
scouring rush, snake grass, or puzzle grass.) In the Paleozoic they grew to 30 meters tall. It is also very
abundant in our coal deposits. They are found on the forest floor where it is damp (low areas) and is common
on the Olympic Peninsula in Washington State (Temperate Rain Forest)
(OPTIONAL: You may want to cut up a straw, and show how the stem is constructed. Each segment can be
pulled apart, like straws inserted inside each other.)
Definitions: A vein is a vascular structure (xylem and phloem cells surrounded by the bundle sheath) in a
leaf that provides supports for the leaf and transports both water and food.
PPT 19: The most common seedless, vascular plants are ferns. (See picture on page 562).
The large groups of leaves are called “fronds”.
The rhizomes grow out horizontally, then roots grow down.
The spores are grouped in tiny “containers” on the underside of the leaves. These are called
sporangia, and the clusters of sporangia are called sori (each “dot” is a mass of sporangia)
The spores are released & carried by the wind or water.
PPT 20: See reproduction cycle on page 563 of textbook.
Note that the fern has a life cycle in which the diploid sporophyte is the dominant life stage.
Homework: 22-3 w.s.
22-4 Seed Plants
Vocabulary: gymnosperm, angiosperm, cone, flower, pollination, seed, embryo, seed coat
Objectives:
22.4.1: Describe the reproductive adaptations of seed plants
22.4.2: Describe the evolution of seed plants
22.4.3: Identify the four groups of gymnosperms
PPT 21: Two groups of flowering plants. Define and describe.
There are 4 groups left of gymnosperms, meaning “naked seed”
Angiosperms have 2 main groups, monocots and dicots. Angiosperm has a seed enclosed in an ovary.
They are usually called “flowering”, or fruit plants.
PPT 22: Plants with seeds do not need to be in a wet area to reproduce. This allows the plants to spread over
a large area. These plants have flowers or cones. They transfer sperm by means of pollination, with
the embryos protected inside the seed.
PPT 23: Do not go into detail here. Reproduction is covered in depth in chapter 24.
Pollen grain: note that water is needed for the sperm to get to the egg. POLLEN => SPERM
Pollination: sperm inside pollen grain is transferred by wind, insects, birds, and small mammals.
(insects get pollen on their legs when they land on a flower. Wind blows ragweed and birch tree
pollen (allergies). Flowering plants that use wind distribution do not produce nectar, or scented
flowers... WHY. Ancestors would be using extra energy to produce nectar when it was not needed;
making nectar would not give them an advantage (not because they don’t “need” it)
Reinforcement: Pollen is male, Fruit/Ovary is female
PPT 24: Labeled diagram to reinforce parts of a seed. Will go into detail in chapter 24
PPT 25: Gymnosperm means “Naked Seed”. Read from text under “Evolution of seed plants” on page 556.
Review 4 phyla of gymnosperms. Note that they used to cover the earth before flowering plants
evolved.
PPT 26: Gnetophytes have separate sexes. Some plants are female and others are male. There are over 70
known species of Gnetophytes. Can reach over 5 feet in hight.
PPT 27: Cycads first appeared during the Triassic period, about 225 million years ago.
They are disappearing in the wild, but have become common garden and landscaping plants in
many southern climates (See a lot of them in Florida). 9 different Genera with over 300 species have
been identified, but we keep finding more. Many species are endangered in the wild. (Note
destruction of rainforest.. Many plants go extinct before we even know there are there).
Very difficult to distinguish male and female plants. They have a thick, wood trunk, and hard, still,
evergreen leaves
PPT 28: Like the Cydads and Gnetophytes, the Ginko has male and female trees.
Ginkoes are the only species left of this phylum. Probably the oldest seed plant species still around.
China planted these plants around their temples. Used in traditional Chinese medicine, the leaves are
used to make medicinal compounds for “thinning the blood, improve muscle tone, and enhance blood
flow”. Today in the U.S., Ginko extracts are sold to “improve mental function”... i.e. memory. At this
time, there is no conclusive evidence for the effectiveness of Ginkgo (mayo clinic website). The trees
are known to live as long as 1000 years. Today the tree is grown in popularity in cities due to its
hardiness and ability to clean polluted air.
PPT 29: Conifers
The conifers are by far the most numerous with over 500 known species. They are often called
“evergreens”. There are bristlecone pines (see textbook page 567) that are nearly 5000 years old. This
group also includes the most massive and tallest plants (tallest is the Giant Redwoods in California,
and the Sequoia is the most massive... heaviest)
FOCUS: Water conservation adaptations: (on homework & test)
1. Modified leaves have less surface area for water to escape
2. Leaves (needles) have a heavy wax coating that restricts water evaporation
3. Pores for gas exchange are located below the surface of the needle to reduce water loss
Another factor in water conservation... When the needles fall off the tree they “weave” together,
making a mat that holds water in the soil. The needles also prevent erosion. Conifers are adapted to
mountain climates, so erosion control is important on slopes!
Show pinecones here, or on page 610 for Reproduction?... or both?
Largest cone is from a sugar pine – tallest pine tree in the world, grow up to 200 feet and 7 ft in dia.
Smallest cone from the Giant Sequoia, the most massive tree.
Record breaker is the “General Grant” tree at 247 feet tall, 27 foot diameter.
Middle size cone is from a Jeffrey Pine, a high altitude species, growing to 130-150 feet height with
4-6 foot diameter.
Questions to end with, or start on...
(Fig 22-23 on p. 568: ask “Predicting...”
What might happen to trees with large flat leaves if they were planted in this environment?
Quickly lose water through leaves, leaves freeze, soil erodes...
22-4 assessment... # 3...
What major change in Earth’s climate favored the evolution of seed plants?
Colder and Drier (some seeds can last for decades)
Homework: 22-4, Seed plants
22-5 Angiosperms - Flowering Plants
Vocabulary: fruit, monocot, dicot, cotyledon, annual, biennial, perennial
(Expect to do seed dissection lab in chapter 24)
Objectives:
22.5.1: Identify the characteristics of angiosperms
22.5.2: Explain the differences between monocots and dicots
22.5.3: Describe the three different life spans of angiosperms
PPT 30: Review the pollination of earlier groups... leave to the wind!
Flowers keep the seed in a protected place. Insects and birds carry the pollen right to the seed
Vocabulary review: Gymnosperm = “naked seed”, Angiosperm = “enclosed seed”
The ovary is called the “fruit”.
PPT 31: After pollination, the ovary develops into a fruit. This structure protects the embryo. The fruit also
allows the plant to spread over an area. When an animal eats the fruit, the plant seeds are spread out
far from the parent plant.
PPT 32: It is difficult to classify angiosperms. We generally divide these plants by using these 3 categories.
These categories may overlap... for example: An iris (see picture) is a monocot (like a grass), but
also a herbaceous perennial (returns year after year).
1. A seed leaf can be seen in a peanut. (Seed dissection in chapter 24?). Ask students if they
have looked at a peanut and seen the leaf inside... or do so when they get a chance.
2. Define herbaceous – meaning “grassy”.
3. annual = survives for 1 year;
biennial = takes 2 years to complete life-cycle 1st grows leaves, stems, and roots (dormant over
winter), then flower and produce seeds the following year... bi=2;
perennial = comes back year after year, energy stored in roots or rhizomes
PPT 33: Characteristics of monocots vs. dicots. Chart on next slide (from text p. 570)
May want to connect back to slide 18...Definition of “veins” (A vein is a vascular structure (xylem
and phloem cells surrounded by the bundle sheath) in a leaf that provides supports for the leaf and transports
both water and food. The veins on monocots are almost parallel to the margins of the leaf. The veins of
dicots radiate from a central midrib.)
PPT 34: Have students find the chart in the text... p. 570
PPT 35: Next division after monocot/dicot is woody or herbaceous “grass-like”.
Examples of woody plants are flowering trees, shrubs and vines (like grapes and ivy). This group also
includes blueberries and roses.
Herbaceous plants do not produce wood. They can still get very tall... a sunflower averages 12 feet!
PPT 36: Read page 572 aloud, or have students read. Note “woody” plants are perennials (trees),
Homework: 22-5 Angiosperms – Flowering plants
Last 4 slides for review of groups (con’t on next page)
PPT 37: Review of categories of angiosperms
(Note slide 38 is answers to diagram)
PPT: 39: Science Starter. Compare/Contrast. Students should complete chart in their notebooks.
Use at the end of the lesson, or to start the next day.
(Note slide 40 is answers to chart)
OTHER POSSIBLE REVIEW:
Understanding concepts (page 575-577)
23. Which group of plants have the most species? flowering (estimated between 250,000- 400,000 species)
31. Applying concepts.
34. Is this picture a monocot or dicot? Why?
p. 577: Standardized test prep (#9-11) Evaluating graphs.
Amy has not yet done the CO2 lab evaluation.
Evolution of plants review (optional).
435 million years ago – plants were green algae
360 million years ago – first bryophytes
290 million years ago – earth is covered by forests and swamps, dominated by ferns, horsetails,
and early conifers
240 million years ago – most horsetails went extinct, first ginkoes and cycads
205 million years ago – ferns and conifers diversify
End of Jurassic period: conifers, cycads, and ferns are dominant
65 million years ago: First flowering plants... cover the land in a few million years