Chapter 21.1
Plant evolution and
Adaptations
Plant Characteristics
Multicellular
 Autotrophic
 Eukaryotes
 Tissues and organs

Green Algae to Plants

Scientists think modern plants may
have evolved from Green Algae
because of similar characteristics…
I Spy…
What are the differences
between these two Autotrophs?
Green Algae
Giant Redwood
Similarities of Plants and Algae
Cell walls w/ Cellulose
 Same type of Chlorophyll
 Food stored as starch
 Enzymes in vesicles
 Similar genes in rRNA
 Cell division w/ cell plate

Similar but not the same
What do you think
plants needed to adapt
to life on land?
A: Bones of course
 B: Reproduce by air and land… not
water
 C: Fed Ex sends weekly care
packages of water
 D: Wet suit… the air dries me out!

4 Plant Adaptations to
Land

Cuticle
– Prevents drying out
– Barrier to microbes
4 Plant Adaptations to
Land

Stomata
– Allows for gas exchange
4 Plant Adaptations to
Land

Vascular tissue
– Allows for
movement of
nutrients &
water
– Provides
support
4 Plant Adaptations to
Land

Seeds
– Survive harsh
conditions
– Food for
developing
embryo
Alteration of
Generations
Gametophyte
produces haploid
(n) gametes
 Sporophyte
produces diploid
(2n) spores

Kingdom Plantae
Nonvascular
1.
2.
3.
Bryophytes- Moss
Antherocerophytes- Hornworts
Hepaticophytes- Liverworts
Vascular without seeds
4.
5.
6.
Lycophytes- Club mosses
Spenophytes - Horsetails
Pterophytes- Ferns
Vascular with seeds
7.
8.
9.
10.
11.
Cycadophytes- Cycads of sago plants
Gnetophytes- Joint firs
Ginkophytes- Ginkgoes
Coniferophytes- Pines
Anthophytes- Flowering plants
Chapter 21.2
Nonvascular Plants
Nonvascular Plants



Small
Requires water
Found in damp,
shady areas
3 Divisions of Nonvascular plants
Bryophyta- Moss
 Anthocerophyta- Hornworts
 Hepaticophyta- Liverworts


Gametophyte is dominant
Division Bryophyta
One cell thick leaf-like
structures
 Rhizoids for anchorage
 Peat – used for fuel,
retain moisture for
gardeners

Moss
Division Anthocerophyta
One large chloroplast in
each cell
 May have symbiotic
relationship with
cyanobacteria

Hornwort
Division Hepaticophyta
Unicellular rhizoids
 Thallose – fleshy,
lobed structures
 Leafy – stems with
thin leaf-like structures
in rows

liverwort
Thallose vs Leafy
Two kinds of Liverwort
Thallose
Leafy
Chapter 21.3
Seedless Vascular Plants
Seedless Vascular
Plants
Have Vascular Tissue
 Larger than Non-vascular
 Better adapted to drier environments
 Strobilus – spore bearing structure
 Sporophyte is dominant
 Division Lycophyta and Pterophyta
(Sphenophyta)

Division Lycophyta



Sporophyte is
dominant
Have roots, stems,
and small, scaly
leaf-like structures
Some are epiphytes
– lives anchored to
another plant or
object

Club mosses
Division
Pterophyta/Sphenophyta
Horsetails or
scouring rushes
 Cell walls of
silica
 Only one genus
= Equisetum


Horsetails - Equisetum
Division Pterophyta


Thick underground
stem – rhizome
(food storage)
Fronds with
sporangia
underneath (sorus)
ferns
Chapter 21.4
Vascular Seed Plants
Vascular Seed plants



Vascular tissue
Cotyledons – food storage for embryo
Seed dispersal
– Wind, water, animal

Sporophyte- dominant life cycle
– Male gametophyte: Pollen
– Female gameophyte: Egg

Produce Seeds
– Gymnosperms: “Naked Seed” without
fruit.
Ex: Pines, fir trees
– Angiosperms: Seeds are part of the fruit
Ex: Apples, peaches, blackberries
5 Divisions of Seed
Plants
Division Cycadophyta
 Division Gnetophyta
 Division Ginkgophyta
 Division Coniferophyta
 Division Anthophyta

Division Cycadophyta


Separate male and
female plants
Found in tropical
and subtropical
environments

Cycad
Division Gnetophyta


Live 1500 – 2000
years
3 genera
– Ephedra – bush


Ephedrine medicine
Found in US
– Gnetum - trees &
climbing vines
– Welwitschia – two
large leaves
Division Ginkophyta

One living species:
– Ginkgo biloba



Fan shaped leaves
Separate male and
female trees
Tolerate pollution
Division Coniferophyta


Shrubs and trees
Economically useful
– Lumber, paper,
turpentine



Male and female
cones on same tree
Scalelike leaves
with cutin
Evergreen – lose
leaves throughout
the year
Leaves

Evergreen- Keep
some green leaves all
year

Deciduous- Lose
leaves once a
year
Division Anthophyta

Flowering plants
Angiosperms
2 kinds of angiosperms

Monocots
– One seed leaf
– Parallel veins in leaves
– Flowers in multiples of 3s
 Monocot examples: grasses,
orchids, lilies, and palms

Dicots/Eudicots
– Two seed leaves
– Netted veins in leaves
– Flowers in multiples of 4s or 5s
 Dicot examples: maples, oaks,
sycamores
 Eudicot examples: trees, shrubs,
flowering plants
Life span of plants

Annual - live for one year
– Most are herbaceous (green stems)
– Have drought resistant seeds
– Examples: corn, wheat, peas, and squash

Biennial - live for two years
– Have large storage roots
– Produce flowers in the second year
– Examples: carrots, beets, and turnips

Perennial – live for many years
– Usually flower once a year
– Examples: maples and oaks