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Chapter 22 Diversity of Plants 22-1 Nonvascular Plants


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Chapter 22 Diversity of Plants

22-1 Nonvascular Plants

  • Small in numbers

  • Need water because of the lack of vascular tissue

  • Small size

  • Gametophyte generation is dominant

  • Gametophyte produces 2 kinds of reproductive features

    • Antheridium – male

    • Archeogonium – female

Adaptations of Bryophyta

  • Mosses

  • Leaves are 1 cell think

  • Upright or creeping stems

  • Occurs in a wide variety of habitats

  • Rhizoids anchor to soil

  • Grows in groups

  • Example: peat moss

Adaptations of Heptophyta

Adaptations of Anthocerophyta

  • 100 species, i.e. hornwarts

  • 1 chloroplast in each cell

Origins of nonvascular plants

  • Liverwarts may be first land plants over 430 mya

22-2 Nonseed vascular Plants

  • Vascular tissue

  • Adapted to changes in water availability

  • Alternation of generation

    • Sporophyte is dominant

  • Leaves are adaptive structures to protect developing reproductive cells

  • Spore bearing leaves form strobilus which releases spores that become gametophytes (prothallus). These form the male and female reproductive parts

Adaptations of Lycophyta

  • Club mosses, spike mosses

  • Has roots, stems, leaves

  • Single vein of vascular tissue

Adaptations of Sphenophyta

  • Horsetails

  • 15 species

  • 1 meter tall

  • Found in marches, stream beds, but also drier environments

  • Reproduce like lycophyta

Adaptations of Pterphyta

  • ferns

  • Appear 400 mya

  • Found in many environments

  • Sporophyte generation has roots, stems, and leaves

  • Main stem is underground (rhizome)

  • Leaves form fronds

  • First to evolve vascular tissue on leaves

  • Fern spores are produced in sporogia. Clusters are called sorus

Origins of non-seed plants

  • 390 mya during the Paleozoic (Carboniferous)

  • Largest species died out over 280 mya

  • Evolution of vascular plants allowed plants to grow larger

22-3 Seed Plants

  • Seeds produced by sporophyte generation

  • Seeds develops into male and female gametophytes

    • Males – pollen

    • Females- ovule

  • Sperm and egg join to form the sporophtye during the process of fertilization. Zygote is formed which develops into an embryo (diploid sporophyte)

  • Most seed plants do need water to reproduce

  • One or more cotyledons (seed leaves that sore and absorb food for the embryo)

Advantage of seeds

  • Food supply for embryo

    • Used by plants until leaves are formed

  • Many form seeds in cones or flowers

    • Called gymnosperms

  • Flowering plants are called angiosperms

Adaptations of Cycadophyta

Adaptations of Ginkophyta

  • Separate male and female plants

  • High tolerance for pollution

Adaptations of Conferophyta

  • Trees and shrubs

  • Pines, firs,

  • Most have male and female origins on different branches

  • Reproductive structures found in cones

  • Most are conifers retain leaves

    • Reproduce in spring

  • Deciduous tress

    • Loose leaves

    • Reduces water loss

Adaptations of Anthophypta

  • 240000 species

  • Roots, stems, and leaves

  • Produce flowers

  • Seeds enclosed in fruit

    • Protects embryo and aids in dispersal

  • Classes:

    • Monocots (1 seed leaf): grasses, orchids, lilies, palms. Leaves in multiple of 3

    • Dicots (2 seed leaves): trees, shrubs, wild flowers. Leaves in multiples of 4 or 5

Life Spans

Annuals- live 1 year. To seed, grow, produce and die; herbaceous (no woody tissue)

Biennials- 2 years; carrots, leaks, turnips

Perennials- 2 + years



Origins of See Plants

  • 300 mya


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