PlantsChapter 19 & 20

The origin of plants from algae Desended from

Charophytes (multicellular green algae) Live around edges of

lakes and ponds Some ancient

charophytes may have lived in shallow-water habitats that occasionally dried out

Natural selection favored algae that could survive the dry periods

Adaptations enabled permanent plant life on dry land 475 million yrs ago

What are plants? Multicellular

Autotrophic

Embryo develops within a mother plant

Eukaryotic

2 (phyla) divisions in plants

1. Bryophytes- do NOT have transport tissue called vascular tissue, thus are nonvascular plants

2. Tracheophytes- do have vascular tissue, so are called vascular plants

Fernsconifers

Flowering Plants

19 Mosses, hornworts, liverworts

Warm-up: (solo on scratch paper)

Identify the 2 phyla/divisions of plants

Identify the characteristic that separates plants into these 2 divisions

Identify major examples of plants that belong to each division

Bryophytes Nonvascular plants grow close to

the ground to absorb water and nutrients.

Seedless plants rely on free-standing water for reproduction.

Liverworts, Mosses Hornworts

19

3 Kinds of Tracheophytes

Pteridophytes :

Gymnosperms

Angiosperms

19

Tracheophyte Facts

Adaptations of tracheophytes to life on land

1. P- protection from drying out

2. E- exchange of gases through leaves

3. T- transport substances

4. S- support

19

Plants have adaptations that allow them to live on land. P-protection from drying out

A cuticle allows plants to retain moisture. waxy, waterproof layer

– holds moisture in

19

E-Exchange of gases on leaves Stomata are tiny holes in the lower epidermis. Guard Cells- open & close stoma

stoma

19

Gurard cell

Plants have adaptations that allow them to live on land.

T- Transport by Vascular Tissue

sugars

water and mineral nutrients

– Xylem: transports water and minerals up from roots to leaves– Phloem: transports food (glucose) from leaves to roots and

shoots

19

xylem

phloem

Plants have adaptations that allow them to live on land.

S- support by cellulose and Lignin

– Allows plants to grow upright– hardens cell walls of some vascular tissues– provides stiffness to stems

plant cells

lignin

19 Plants have adaptations that allow them to live on land.

Bryophytes

Nonvascular plants grow close to the ground to absorb water and nutrients.

Seedless plants rely on free-standing water for reproduction.

Liverworts, Mosses, and Hornworts

VIDEO Alternation of Generations: The sex life of Bryophytes• What is meant by “Alternation

of Generations”?• What is the difference

between gametophytes and sporophytes?

Pteridophytes (Club mosses and ferns) are seedless vascular plants.

Characteristics/Adaptations:

Vascular tissue

Seedless

Ferns, Club Mosses, and Horsetails

19

Fern

Club Moss

Horsetails

Tracheophyte #1 www.brainpop.com/science/diversityoflife/seedlessplants/

Ferns Sori form under the

fronds

Rhizoids

Rhizomes

Fiddlehead

19

Video

Fern Life Cycle:• What are Rhizoids• What is the difference btwn

antheridium and archaegonium?• What is the function of anteridiogen?

Gymnosperms Plants that bear seeds that are “Naked” (not enclosed by an ovary)

can reproduce without free-standing water, via pollination

– ADAPTATIONS– Vascular Tissue– Pollen Grains (male

gametophyte)– Naked Seeds (embryo &

food supply)– seeds allow plants to

disperse to new places

19 Tracheophyte #2

www.brainpop.com/science/diversityoflife/seedplants/

video Vascular Plants

Gymnosperms do have naked seeds (not enclosed by a fruit).

19

CYCADSCONIFERS

GINKGOS

Angiosperms (flowering plants) – Adaptations:

– vascular tissue– Flowers (reproductive

structure)– Seeds develop within

ovaries– Fruit- ripened ovary

19 Tracheophyte #3

video

Structure of a Flower

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Monocots VS Dicots

Work with your face partner…

Create two lists that describe the characteristics of monocots and dicots

Classes of Angiosperms19

DICOTS

1 cotyledo

n

2 cotyledon

s

Monocots and Dicots (classes of Angiosperms)

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lily

grass

Oak tree

Cherry Tree

Fig. 19-5

                                                        

                                                             

1. Which group of algae has been hypothesized to be the ancestor of plants?

2. Which group of plants evolved most recently?

3. What main adaptation separated the pteridophytes from bryophytes?

4. In which group of plants did seeds first appear?