kingdom plantae. how plants came to be overview of the plant kingdom botanists divide the plant...
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Kingdom Plantae
How Plants came to be
Overview of the Plant Kingdom
• Botanists divide the plant kingdom into four groups based on three important features:
1. Water conducting tissues2. Seeds3. Flowers
Mosses
Ferns
Cone Bearing Plant
Flowering plant
The Plant Life Cycle• Plants have life cycles that are
characterized by alternation of generations• The two generations are the haploid
(N) gametophyte, or gamete-producing plant, and the diploid (2N) sporophyte, or spore-producing plant.
Bryophytes • Type of early plant with no vascular
tissue that draw water in their cells by osmosis.
Moss
Liverwort
Hornwort
• In just a few million years, plants grew to a whole new scale on the landscape.
Q: What caused this increase in size? A: Vascular Tissue
Vascular tissue • A type of tissue that is specialized to
conduct water and nutrients through the body of the plant
Evolution of Vascular Tissue
• Both forms of vascular tissue—xylem and phloem—can move fluids throughout the plant body, even against the force of gravity.
Xylem
• Carry water upwards from the roots to every part of the plant
Phloem• Transports nutrients and
carbohydrates produced by photosynthesis from the leaves down to the roots
22–3 Seedless Vascular Plants
Club Mosses
Horsetails
Ferns
Underground Stem
• Over millions of years, plants with a single trait—the ability to form seeds—became the most dominant group of photosynthetic organisms on land.• Seed plants are divided into two
groups:
Gymnosperms
• Cone plants• Bear their seeds directly on the
surfaces of conesEx.) conifers, pines, spruces, cycads,
ancient ginkgoes and gnetophytes
Angiosperms• Flowering plants• Bear their seeds within a layer of
tissue that protects the seedEx.) grasses, flowering trees shrubs,
wild flowers
Monocots and Dicots• Monocots and dicots are named for
the number of seed leaves, or cotyledons, in the plant embryo. Monocots have one seed leaf, and dicots have two seed leafs
Flowers
• Seed bearing structures of angiosperms
Pollen
Entire Male Gamtophyte
Pollen grain • Contains the male gamete
Pollination
• The transfer of pollen from the male gametophyte to the female gametophyte
Seed Coat• Surrounds and protects the embryo
and keeps the contents of the seed from drying out• Can be specialized for dispersal
Flowers and Fruits• Angiosperms have unique
reproductive organs known as flowers.
Q: Why are flowers evolutionary adaptations?
A: they attract animals that pollinate them
• Flowers contain ovaries, which surround and protect the seeds
• After pollination, the ovary develops into a fruit, which protects the seed and aids in its dispersal.
Fruit • Ripened ovary, thick wall of tissue
that surrounds the seed• Hard, tart fruit protects developing
seed from herbivores• Ripe, sweet, soft fruit attracts animals to disperse seeds
Which Plants have better adapted to live on land?
• Vascular plants also evolved the ability to produce lignin, a substance that makes cell walls rigid. • The presence of lignin allows
vascular plants to grow upright and tall
Roots• Absorb water
and minerals
Leaves• Collect light for photosynthesis
Veins • Made of xylem and phloem
Stems • Used for
support, connect roots and leaves, carry water between them
Woody and Herbaceous Plants
• Woody plants – Have woody stems
Ex.) trees, shrubs, vines
Herbaceous Plants • Plant stems that are smooth and
nonwoodyEx.) dandelions, petunias, and
sunflowers
Annuals, Biennials, and Perennials
Annuals
• Angiosperms that complete a life cycle within one growing season
Biennials • Angiosperms that complete their life
cycle in two years• In the first year, biennials germinate
and grow roots, stems, leaves• During their second year, biennials
grow new stems and leaves and then produce flowers and seeds
Perennials • Flowering plants that live for more
than two years