Ch 22- Plant Diversity
• What is a plant?
– Multicellular eukaryotes, have cell walls made of cellulose
– Carry out photosynthesis using pigments-chlorophyll a and
b
• Welcome to Discovery Education Player
• Plant Life Cycle
– Sporophyte- diploid phase produces spores
– Gametophyte- haploid phase produces gametes
• What do plants need to survive?
– Sunlight, water and minerals, gas exchange, and transport
of water and nutrients
• First plants evolved from organism similar to
modern multicellular green algae
• 4 groups in plant kingdom based on waterconducting tissues, seeds and flowers
– Mosses and their relatives
– Ferns and their relatives
– Cone-bearing plants
– Flowering plants
Sec 2- Bryophytes
• Bryophytes- nonvascular plant
– Depend on water for reproduction
– Mosses
• What adaptations of bryophytes enable them
to live on land?
– Can draw up water by osmosis a few cm above
ground
• Three main groups of bryophytes
– Mosses, liverworts, and hornworts
• 3 phyla of non-vascular called Bryophytes
– Mosses belong to Phylum Bryophyta
– Others include liverworts and hornworts
• Characteristics include
– Usually grow on land near streams and rivers
– Most primitive type of plant and abundant in polar
regions
– Closely related to algae and most terrestrial
– Need water to reproduce sexually
– Contain rhizoids-false roots-root like structure that
anchors moss and absorbs nutrients
• Life cycle of bryophytes
– Gametophyte is dominant stage
– Antheridia- male reproductive structure
– Archegonia- female reproductive structure
Sec 3- Seedless Vascular Plants
• Vascular tissue- type of tissue that transports water and dissolved
substances from roots to leaves
– Types include xylem and phloem
• Xylem transports water made up of tracheids- hollow cells with thick cell walls that
resist pressure
• Phloem transports organic compounds
• Can move fluids against gravity
• Seedless vascular plants- club mosses, horsetails, and ferns
– Ferns have underground stems called rhizomes and fronds which are large
leaves
• What are the characteristics of three phyla of seedless vascular
plants?
– Roots, leaves, veins, stems
– Roots- underground organs that absorb water and minerals
– Leaves- photosynthetic organs, contain one or more bundles of vascular
tissue
– Veins- vascular tissue in leaves made of xylem and phloem
– Stems- supporting structures, connect roots and leaves, carry water and
nutrients
Life Cycle of Ferns
• Diploid sporophyte is dominant stage in ferns
and other vascular plants
• Sporangia- structure in ferns that contains
spores, diploid
• Sori- cluster of sporangia on underside of a
fern frond
Sec 4- Seed Plants
• Gymnosperms- seed plants that bear seeds
directly on surface of cones
– Gymnosperm means “naked seed”
– Conifers such as pines and spruces, cycads, ancient
ginkgoes
• Angiosperms- flowering plants that bear their
seeds within layer of tissue that protects seed
• What adaptations allow seed plants to reproduce
without standing water?
– Flowers or cones- allow transfer of sperm by
pollination and protection of embryos in seeds
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Cones- seed bearing structure
Flowers- seed bearing structure of angiosperm
Pollen grain- male gametophyte in seed plants
Pollination- transfer of pollen from male reproductive
structure to female reproductive structure
Seed- embryo of living plant that is encased in protective
covering
Embryo- organism in its early stage of development
Seed coat- structure that surrounds and protects a plant
embryo and keeps it from drying out
What are the four groups of gymnosperms?
– Gnetophytes, cycads, ginkgoes, and conifers
– All reproduce with seeds
• Conifers- most common
– Includes pines, cedars, spruces, redwoods, sequoias, junipers
Sec 5- Angiosperms
• Angiosperms- members of phylum
Anthophyta, originated on land
• What are the characteristics of angiosperms?
– Flowers- reproductive organs
– Flowers contain ovaries- surround and protect the
seeds
– Fruit- wall of tissue surrounding the seed
Diversity of Angiosperms
• What are monocots and dicots?
– Named for # of seed leaves, or cotyledon- first leaf or
first pair of leaves produced by embryo of seed plant
• Monocots- single cotyledon, parallel veins,
flowers in multiples of 3’s, vascular bundles
scattered throughout stem, fibrous roots
– Corn, wheat, lilies
• Dicots- two cotyledon, branched veins, flowers in
multiples of 4 or 5, vascular bundles in ring,
taproot
– Roses, tomatoes, oaks
• Woody plants- thick cell walls
– Trees, shrubs, vines
• Herbaceous- smooth and nonwoody stems
– Dandelions, sunflowers
• What are the three categories of plant life spans?
– Annuals- flowering plants that complete a life cycle
within one growing season
• Wheat
– Biennials- flowering plants that complete life cycle in 2
yrs
• Celery
– Perennials- flowering plants that live for more than 2
yrs
• Asparagus, palm and maple trees