Chapter 21 Introduction to Plants Section 1: Plant Evolution and Adaptations Section 2: Nonvascular...

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Chapter 21 Introduction to Plants Section 1: Plant Evolution and Adaptations Section 2: Nonvascular Plants Section 3: Seedless Vascular Plants Section 4: Vascular Seed Plants

Transcript of Chapter 21 Introduction to Plants Section 1: Plant Evolution and Adaptations Section 2: Nonvascular...

Page 1: Chapter 21 Introduction to Plants Section 1: Plant Evolution and Adaptations Section 2: Nonvascular Plants Section 3: Seedless Vascular Plants Section.

Chapter 21 Introduction to Plants

Section 1: Plant Evolution and Adaptations

Section 2: Nonvascular Plants

Section 3: Seedless Vascular Plants

Section 4: Vascular Seed Plants

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When scientists compare present-day plants and algae, they find the following common characteristics:

21.1 Plant Evolution and Adaptations

Introduction to PlantsChapter 21

cell walls composed of cellulose cell division that includes the formation of

a cell plate the same type of chlorophyll used in

photosynthesis similar genes for ribosomal RNA food stored as starch the same types of enzymes in cellular vesicles

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Cuticle

Introduction to Plants

Helps prevent the evaporation of water from plant tissues

Acts as a barrier to invading microorganisms

21.1 Plant Evolution and Adaptations

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Stomata

Introduction to Plants

Allows exchange of gases through the cuticle

Openings in the outer cell layer of leaves and some stems

21.1 Plant Evolution and Adaptations

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Vascular Tissues

Introduction to Plants

Vascular tissue enables faster movement of substances over greater distances.

Vascular tissue provides support and structure, so vascular plants can grow larger than nonvascular plants.

21.1 Plant Evolution and Adaptations

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Seeds

Introduction to Plants

A plant structure that contains an embryo, nutrients for the embryo, and is covered with a protective coat

These features enableseeds to survive harsh environmental conditions and then sprout when favorable conditions exist.

21.1 Plant Evolution and Adaptations

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Alternation of Generations

Introduction to Plants

Gametophyte generation produces gametes.

Sporophyte generation produces spores These can grow to form the next

gametophyte generation.

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During plant evolution, the trend was from dominant gametophytes to dominant sporophytes that contain vascular tissue.

Introduction to Plants

1000x

Sporophyte generation—maple tree Gametophyte generation—maple pollen

21.1 Plant Evolution and Adaptations

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Introduction to Plants

21.1 Plant Evolution and Adaptations

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Introduction to Plants

Non-Vascular Plants

Bryophyta

Anthocerophyta

Hepaticophyta

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Diversity of Nonvascular Plants Division Bryophyta

21.2 Nonvascular Plants

Introduction to Plants

Most familiar bryophytes are the mosses. Structures that are similar to leaves

Rhizoids

Carpet of mossLeafy stems

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Introduction to Plants

Water and other substances move throughout a moss by osmosis and diffusion.

21.2 Nonvascular Plants

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Produce rootlike, multicellular rhizoids that anchor them to soil or another surface

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Division Anthocerophyta

Introduction to Plants

Anthocerophytes are called hornworts.

Water, nutrients, and other substances move in hornworts by osmosis and diffusion.

Hornwort

21.2 Nonvascular Plants

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Identifying Features

Introduction to Plants

One large chloroplast in each cell of the gametophyte and sporophyte

Spaces around cells are filled with mucilage, or slime.

Cyanobacteria grow in this slime.

21.2 Nonvascular Plants

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Division Hepaticophyta

Introduction to Plants

Hepaticophytes are referred to as liverworts.

Found in a variety of habitats

Water, nutrients, and other substances are transported by osmosis and diffusion.

21.2 Nonvascular Plants

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Most primitive of land plants

Introduction to Plants

Thallose liverwort

Leafy liverwort

21.2 Nonvascular Plants

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Introduction to Plants

Seedless Vascular Plants

Lycophytes

Pterophytes

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Introduction to Plants

Contain vascular tissue

21.3 Seedless Vascular Plants

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Have roots, stems, and small, scaly, leaflike structures

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Vascular Tissue• Xylem

– Tissue that carries water

• Phloem– Transports solutions of

nutrients and carbs (food)

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Sporophyte produces roots and a thick underground stem called a rhizome, a food-storage organ.

Introduction to Plants

The frond is part of the sporophyte generation of ferns.

21.3 Seedless Vascular Plants

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Introduction to Plants

Fern spores form in a structure called a sporangium.

Clusters of sporangia form a sorus.

Sori usually are located on the undersides of fronds.

Bird’s nest fern

21.3 Seedless Vascular Plants

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Diversity of Seedless Vascular Plants

Division Lycophyta Reproductive structures producespores that areclub-shaped orspike-shaped(thallose).

21.3 Seedless Vascular Plants

Introduction to Plants

Lycopodium—wolf’s claw

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Division Pterophyta

Introduction to Plants

Includes ferns and horsetails

Staghorn fern Hawaiian fern

Aquatic fern

Dryopteris

21.3 Seedless Vascular Plants

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Introduction to Plants

Seed-producing Vascular Plants

Cycadophytes

Gnetophytes

Ginkgophytes

Coniferophytes

Anthophytes

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Diversity of Seed Plants Many adaptations for the dispersal of seeds.

21.4 Vascular Seed Plants

Introduction to Plants

The sporophyte is dominant

Pine seedCocklebur

Witch hazel

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Division Cycadophyta

Cones contain male or female reproductive structures of cycads and other gymnosperm plants.

Introduction to Plants

Evolved before plants with flowers

The natural habitats for cycads are the tropics or subtropics.

21.4 Vascular Seed Plants

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Division Gnetophyta

Can live as long as 1500–2000 years

Introduction to Plants

Three genera of gnetophytes

Ephedrine is a compound found naturally in gnetophytes.

Welwitschia

21.4 Vascular Seed Plants

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Division Ginkgophyta

Only one living species, Ginkgo biloba

Introduction to Plants

Has small, fan-shaped leaves

Female

Male and female reproductive systems are on separate plants

Male

21.4 Vascular Seed Plants

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Division Coniferophyta Reproductive structures of most conifers develop

in cones.

Introduction to Plants

Male and female cones on different branches Waxlike coating called cutin reduces water loss.

Douglas fir—woody cones Juniper—berrylike cones Pacific yew—fleshy cones

21.4 Vascular Seed Plants

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Division Anthophyta

First appeared in the fossil record about 130 million years ago

Introduction to Plants

Botanists classify anthophytes as monocots, dicots, or eudicots.

First flowering plants (angiosperms), evolved after gymnosperms

21.4 Vascular Seed Plants

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A biennial plant’s life spans two years.

Perennial plants can live for several years and usually produce flowers and seeds yearly.

Introduction to Plants

First-year growth

Second-year growth

21.4 Vascular Seed Plants

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