Plants•Cellulose cell walls

•Almost all photoautotrophic

•Nearly all terrestrial

•295,000 Species

Vascular vs. Non-Vascular

• Vascular- have internal tissues that conduct water– Xylem- Transports water– Phloem- Transports sugars

• Non-Vascular- lack these tissues– Ex: Mosses

Roots and Shoots

• Shoots-stems and leaves, absorb energy and CO2

• Roots- underground absorptive structures

Plant Sex(Alternation of Generation)

zygote

SPOROPHYTE (2n)

GAMETOPHYTE (n)

GREEN ALGA BRYOPHYTE FERN GYMNOSPERM ANGIOSPERM

• Most plants are hermaphrodites, both male and female

• Seedless plants- ferns, horsetails• Seed-bearing plants

– Seeds- ‘A baby in a box with a lunch’– Gymnosperms- open fertilization

• Conifers and Ginkos

– Angiosperms- closed fertilization• Flowering plants

Making Babies

Baby in Box With a Lunch

Fern Lifecycle

Parts of a flower

Non-Vascular Plants

– Bryophytes- 18,600 species• Mosses, liverworts and hornworts• The simplest plants• Non-vascular • All <8 inches tall• Many have rhizoids

Bryophytes (mosses)

Seedless Vascular Plants

• Whisk Ferns, Lycophytes, Horsetails and Ferns

• They have true vascular tissue.

• Most live in wet, humid places and the gametophytes lack vascular tissues.

Sporophyte of Lycopodium

Figure 15.8aPage 253

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Equisetum

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Tree ferns (Cyathea)

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Seed-Bearing Plants

• Produce Microspores which give rise to pollen

• Produce Megaspores, which give rise to the egg cells

• These adaptations are advantages in cooler, drier climates

Conifers

• Woody trees and shrubs that have cones– Cones- clusters of modified leaves that

surround the spore-producing structures

• Most are evergreen, and a few are deciduous.

• This group includes the tallest (coast redwoods >100m) and oldest (bristlecone pine 4,725 years old)

Fig. 15.13(1)Page 257

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Conifer Lifecycle

Angiosperms

– The flowering plants– 260,000 species– The enlarged ovary where the seed

develops is the fruit.– Most coevolved with pollinators– Range in size from duckweed (<1cm) to

eucalyptus trees (>100m)– Two Classes

• Dicots• Monocots

Figure 15.14Page 258

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millions of years ago

nu

mb

er of g

enera

other genera

200

ginkgo

cycads

ferns

angiosperms

150

100

50

0160 140 120 100 80 60

conifers

250

mature sporophyte (2n)

ovules inside ovary

pollen sac

Meiosis Meiosis Double Fertilization Diploid StageHaploid Stage

seed

meiosis and two rounds of mitosis without any cytoplasmic division

haploid (n) microspores

male gametophyte

Pollen is released

Pollen tube enters ovule female gametophyte

egg

haploid (n) megaspore

Fruits