Chapter 22
Plant Diversity
Key Concepts:
- What is a plant?
- What do plants need to survive?
- How did the first plants evolve?
Vocabulary
- Gametophyte
- Sporophyte
- Section 22-1 Introduction to plants
- What is a plant?
- They are
- multicellular
- eukaryotes
- that have cell walls make of cellulose
- they develop from multicellular embryos
- carry out photosynthesis using green pigments
- chlorophyll α
- and b
- The plant Life cycle
- Is characterized by alternation of generations
- one sexual
- gametophyte-
- gamete-producing- haploid- plant
- one asexual
- sporophyte-
- spore producing plant
- What plants need to Survive
- Lives of plant revolve around the need for
- sunlight
- carryout photosynthesis
- leaves are typically broad and flat
- water and minerals
- all cells require a constant supply of water
- water is need for photosynthesis
- gas exchange
- require oxygen to support respiration
- require carbon dioxide to carry out photosynthesis
- movement of water and nutrients throughout the plant body.
- Use roots
- Specialized tissue- Vascular Tissue
- Xylem
- phloem
- Early Plants
- Origins believed to be in water
- first plants evolved from an organism much like multicellular green algae
- Overview of the Plant Kingdom
- Botanists divide the plant kingdom into four groups based on three features
- water-conducting tissue Vascular
- seeds
- flowers
- Pie chart pg. 555
Key concepts:
- What adaptations of bryophytes enable them to live on land?
- What are the three groups of bryophytes?
- How do bryophytes reproduce?
Vocabulary:
1
22 Plant Diversity
- Bryophyte
- Rhizoid
- Gemma
- Protonema
- Anteridium
- Archegonium
1
22 Plant Diversity
- Section 22-2 Bryophytes Non- Vascular
- Bryophytes –
- have live cycles that depend on water for reproduction.
- Lack vascular tissue
- Draw up water by osmosis on a few centimeters, so they are short
- Groups of Bryophytes- low growing plants
- Mosses- phylum Bryophyta
- most common
- grow abundantly in area of water
- lack vascular tissue
- do not have roots
- have rhizoids
- Liverworts- look like leaves growing on the ground
- Hornworts-look like a tiny green horn
- Live cycle of Bryophytes
- The gametophyte is the dominant stage
- The stage the carries out photosynthesis
- Dependence on water-water carries the gamete and therefore bryophytes are dependent on water
- Live cycle of moss pg. 558
- Human Uses of Mosses
- Sphagnum- absorbs many times its own weight
- Peat moss- used in gardening to help retain water for other plants
Key concepts:
- How is vascular tissue important to ferns and their relatives?
- What are the characteristics of the three phyla of seedless vascular plants?
- What are the stages in the life cycle of ferns?
Vocabulary:
1
22 Plant Diversity
- Vascular tissue
- Tracheid
- Xylem
- Phloem
- Lignin
- Root
- Vein
- Leaf
- Stem
- Rhizome
- Frond
- Sporangium
- Sorus
1
22 Plant Diversity
- Section 22-3 Seedless Vascular Plants
- Vascular tissue-tissue that conducts the transport of water and nutrients
- Evolution of Vascular Tissue
- Tracheids- cells that are in the tissue
- Xylem- tissue that carries water
- Phloem- tissue the transports nutrients
- Can produce Lignin- substance that makes the cell wall rigid
- Ferns and Their Relatives
- Seedless vascular plants include
- club mosses,
- today are huge bed of coal
- small plants that live in moist woodlands
- called a ground pine pg 561
- horsetails,
- has leaves that are arranged in whorls at joints
- contains abrasive silica
- ferns
- more than 11,000 species
- has underground steams called rhizomes
- large leaves called fronds
- Life Cycle of Ferns
- Ferns and other vascular plants have a life cycle in which the diploid sporophyte is the dominant stage.
- reproduction is dependent on a thin film of water
Key Concepts:
- What adaptations allow seed plants to reproduce without standing in water?
- What are the four groups of gymnosperms?
Vocabulary:
1
22 Plant Diversity
- Gymnosperm
- Angiosperm
- Cone
- Flower
- Pollen grain
- Pollination
- Seed
- Embryo
- Seed coat
1
22 Plant Diversity
- Section 22-4 Seed Plants-Vascular
- Two main groups
- Gymnosperms-
- the seeds are directly on the surface of the cone or naked seeds
- include conifers- pines and spruces
- Angiosperms-
- their seeds are within a layer of tissue
- grasses, flowering trees, and shrubs
- Reproduction free from water
- Adaptations that allow seed plants to reproduce without water include
- flowers or cones,
- the gametophytes grow to mature in a cone in gymnosperms
- the gametophytes mature in a flower in angiosperms
- the transfer of sperm by pollination
- the male gametophyte is contained in the pollen grain.
- the pollen is carried by wind, insects, birds, or small animals or even your car.
- the transfer of pollen is called pollination
- the protection of the embryos in seeds.
- the seed
- is the embryo of a plant
- encased in a protective coating
- with a food supply
- Evolution of Seed Plants-evolved from mosses and ferns
- Gymnosperms –Cone Bearers
- Gymnosperms include
- gnetophytes, -
- have reproductive scales clustered in cones
- pg 566
- cycads,
- palmlike plants
- reproduce with large cones
- ginkgoes,
- only one species, Ginkgo Biloba
- are tough and resistant to air pollution
- conifers
- most common gymnosperms
- phylum coniferophyta
- Ecology of conifers
- Grow in dry conditions
- Most are evergreens
- Have needles
Key Concepts:
- What are the characteristics of angiosperms?
- What are monocots and dicots?
- What are the three categories of plant life spans?
Vocabulary:
1
22 Plant Diversity
- Fruit
- Monocot
- Dicot
- Cotyledon
- Annual
- Biennial
- Perennial
1
22 Plant Diversity
- Section 22-5 Angiosperms-Flowering Plants
- Flowers and Fruits
- Have reproductive organs known as flowers.
- Flowers contain ovaries, which surround and protect the seeds
- Angiosperms means enclosed seed
- After pollination the ovary develops into a fruit which protects the seed
- Diversity of Angiosperms
- Can be categorized by
- monocots and dicots
- woody and herbaceous
- annuals, biennials, and perennials
- the categories can overlap
- Monocots and Dicots
- named for the number of seed leaves, or cotyledons, in the embryo
- monocots- have one seed leaf
- dictos- have two seed leaves
- they have other characteristics Table 22-25
Monocots / Dicots
- Woody and Herbaceous Plants
- woody plants
- are made of thick cell walls the support the plant
- include trees, shrubs, and vines
- Hervaceous Plants
- Are smooth and nonwoody
- Examples: dandelions, zinnias, pentunias, and sunflowers.
- Annuals, Biennials, and Perennials
- annuals-once a year and die
- Biennials- life cycle last for two years on the second year they flower
- Perennials-live for more than two years
1
22 Plant Diversity