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