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: Water conducting tissues Seeds 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 cones Ex.) conifers, pines, spruces, cycads, ancient ginkgoes and gnetophytes

Angiosperms Flowering plants Bear their seeds within a layer of tissue that protects the seed Ex.) 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

Entire Male Gamtophyte 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 nonwoody Ex.) 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