Download Plant Evolution and Diversity B. Importance of plants C. Where do

Plant Evolution and Diversity
Reading: Chap. 30
I. What is a plant?
A. Basic structure and function
B. Why are plants important?
C. What are plants, evolutionarily?
D. Problems of living on land
II. Overview of major plant taxa
A. Bryophytes (seedless, nonvascular)
B. Pterophytes (seedless, vascular)
C. Gymnosperms (seeds, vascular)
D. Angiosperms (seeds, vascular, and flowers+fruits)
II. Major evolutionary trends
A. Vascular tissue, leaves, & roots
B. Fertilization without water: pollen
C. Dispersal: from spores to bare seeds to seeds in fruits
D. Life cycles Æ reduction of gametophyte, dominance of sporophyte
B. Importance of plants
1. Food – agriculture, ecosystems
2. Habitat
3. Fuel and fiber
4. Medicines
5. Ecosystem services
A. Plants: fundamentals
What does it do?
- Photosynthesize
- CO2 uptake
- O2 release
- Water loss
- Water and nutrient uptake
- Grow
Where? Which directions?
- Reproduce
Fig. 1.10, Raven et al.
C. Where do plants fit, evolutionarily?
How are protists related to higher plants?
Algae are eukaryotic photosynthetic organisms
that are not plants.
Relationship to the protists
What are the defining traits of plants?
- Multicellular, eukaryotic, photosynthetic autotrophs
- Cell chemistry:
- Chlorophyll a and b
- Cell walls of cellulose (plus other polymers)
- Starch as a storage polymer
- Most similar to some Chlorophyta: Charophyceans
Fig. 29.8
Points
1.
2.
3.
Photosynthetic protists are spread throughout many groups.
Plants are most closely related to the green algae, in particular, to the
Charophyceans.
Plantae has expanded to include green algae, red algae and glaucophyte
algae. What is in common?
Coleochaete
Chara
1
All “Land” plants
“Land” plants only
(some but not all green algae)
- Alternation of generations (sporic life cycle)
- Apical meristem
C&R 29.3
C&R 29.6
“Land” plants only
“Land” plants only
- Multicellular, dependent embryos Æ “Embryophytes”
- Multicelluar gametangia:
antheridia and archegonia
Moss life cycle
30.20
30.13
29.17a
The Phylogeny of Green Plants
ria ea
te ha
ac rc
B A
Eukarya
Green plants
30.14
D. Problems of land life:
Adaptations for living in air
Land plants
Vascular plants
Seed plants
e
ea
yc
e
ph )
a
ae s) to tes ea s)
yt )
ce e ae e yc rt
phlgae hy hyt ch cha ph wo
o
e
a
p
o
o
d a
r n
op o e
ho(red lv (ulv ol (cole ha (sto
R
C
C
U
Gymnosperms
a
yt
ta
ph )
hy )
op rts ro rts ta )
ic o ce o hy es
at rw ho rnw op ss
ep (live nt (ho ry (mo
H
A
B
Angiosperms
)
)
rs t al.
)
a
a
a
a )
ta
ta rms
yt
yt
ife e ta tes a l.)
yt
yt ns hy s)
a s)
ph ) ph ) on ds hy hy yt t a hy pe
yt yte
ph fer p ail ph
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do ds go go r c oo op top ph s e op ios
ph ph
ca yca ink ink the edw net ne ino ine nth ng
ilo his phe ors teri ern
co co
y
s
y
g
c
w
r
f
h
ly
P ( S ( P (
C ( G ( O ( G (g P (p A (a
L (
Flowers
Seeds
Vascular tissue
Green algae
Nonvascular plants
Ability to live on land
Chloroplasts containing chlorophyll a + b and β-carotene
Seedless vascular plants
2
1. Desiccation of plant
2. Resource
acquisition - water
and minerals
Fig. 30.10
- Roots
REE, Fig. 1.10
- Water conservation - epidermis w/cuticle,
stomata, guard cells
REE, Fig. 1.10
4. No water for reproduction
3. Light acquisition
a. gamete dispersal and desiccation
b. spore dispersal and desiccation
C&R Fig. 29.7
a. Surface area
- Leaves
b. Fight gravity
- Support
c. Fluid transport
- Vascular tissue, xylem and phloem
Fig. 1.10
II. Overview of Taxa
- Fertilization and dispersal that are independent of water (some).
1. Bryophytes
Liverworts (Hepaticophyta)
~6500 species, moist
environments
Hornworts
(Anthocerophyta)
~100 species
Mosses (Bryophyta)
~12,000 species,
widespread
3
Bryophyte ecology:
a. Groundcover and epiphytes
Bryophyte ecology: b. Global carbon cycle
Groundcover
Epiphytes
What’s new?
B. Seedless vascular plants (Pteridophytes)
1. Vascular tissue, true leaves, true roots
2. Sporophyte dominant
Lycophyta
- “club
mosses”
Psilotophyta
Sphenophyta
Pterophyta
30.17b
Other SVP developments: true leaves
Other SVP developments: true roots
Moss phyllids
http://www.palaeos.com/Plants/Bryophyta/Bryophyta.html
Angiosperm, Fig. 29.10
Club moss, REE Fig. 19-3
4
Figure 30-9
1. Gymnosperms: Who are they?
C. Seed plants - Gymnosperms
ria ea
te ha
ac rc
B A
Eukarya
Green plants
Land plants
Vascular plants
Seed plants
e
ea
yc
e
ph )
a
ae ) to tes ea s)
yt )
ce es ae e yc rt
phlgae hy hyt ch cha ph wo
o
e
a
p
o
d a
op o e o r n
ho(red lv (ulv ol (cole ha (sto
R
C
C
U
Gymnosperms
a
yt
ta
ph )
hy )
op rts ro rts ta )
ic o ce o hy es
at rw ho rnw op ss
ep (live nt (ho ry (mo
H
A
B
Angiosperms
)
)
rs t al.
)
a
a
a
a )
ta
)
ta rms
yt
yt
ife e ta tes a l.)
yt
yt ns hy s)
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do ds go go r c oo op top ph s e op ios
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ca yca ink ink the edw net ne ino ine nth ng
ilo his phe ors teri ern
colyco
y
s
y
r
g
c
w
f
h
P ( S (
C ( G ( O ( G (g P (p A (a
L (
P (
Flowers
Seeds
Vascular tissue
Green algae
Nonvascular plants
Ability to live on land
Chloroplasts containing chlorophyll a + b and β-carotene
Phyla:
Ginkgophyta - 1 genus, 1 species: Ginkgo
biloba
Cycadophyta - ~100 species
Conifers - 550 species: Pinophyta & “other”
(redwoods, cypresses, junipers, etc.)
Gnetophyta - 3 genera, 70 spp.
Seedless vascular plants
Conifers
Conifers
Biggest
Giant sequoia
Tallest?
Coast redwood
Conifers
oldest
Bristlecone pine – 4795
in 2007
Conifers
Furthest north
White spruce
highest
5
Conifers
Conifers
Widespread (boreal forest,
temperate rain forest)
Very important timber species
Most photographed
Monterey cypress
http://www.pc.gc.ca/canada/nature/archives/2003/fe/
ART_IMAGES/map_boreal.gif
Conifers
Conifers
Wet conditions
Dry conditions
Black spruce
Juniper
D. Seed plants: Angiosperms
(Phylum Anthophyta)
3. What’s new?
~270,000 species
Land plants
Vascular plants
Seed plants
ds
in
kg
R o
ed
w
G oo
ne d
to s e
P i p h t al
ne yte .
s
s
e
A
n g t al
io .
sp
er
m
s
yc
a
C
G
s
yt
e
H
or fern
se
s
t
Fe ails
rn
s
ph
k
hi
s
Ly
co
W
er
w
o
H
or rts
nw
or
M
ts
os
se
s
Li
v
al
ga
e
op
hy
C
te
ol
eo s
ch
ae
St
on
te
s
ew
or
ts
Gymnosperms
R
ed
Secondary growth
Continued g’phyte reduction
Pollen and heterospory
Seeds
U
lv
a.
b.
c.
d.
Fruit
Flowers
Heterospory
Seeds
Pollen
Heterospory
Fruit
Sporophyte-dominated life cycle
Green algae
Nonvascular plants
Seedless vascular plants
Alternation of generations
Retention of embryo on parent
Complex gametangia
Thick-walled spores
Retention of egg on parent
Simple gametangia
Figure 30-26
6
1. Who are they?
2. Why are they important?
Monocots:
~ 60,000 spp.
Lilies, orchids,
grasses, palms
Dicots:
Most of the rest
Trees, shrubs, forbs
Eudicots and ‘other’
a. Most diverse phylum, huge radiation
b. Base of many terrestrial food webs
c. Basis of agriculture
Fruits
Vegetables
Grains
d. Secondary compounds – drugs, medicines
III. Major Evolutionary Trends
A. What is “vascular tissue”
and what does it do?
1. Xylem
A. Structure: Vascular tissue, leaves, & roots
B. Reproduction: Fertilization without water: pollen
C. Reproduction: Dispersal of progeny: from spores to
bare seeds to seeds in fruits
D. Life cycles Æ reduction of gametophyte, dominance
of sporophyte
- water and nutrients up from
roots to stem, leaves: one way
- hollow
- dead at maturity
- secondary cell walls, lignin
2. Phloem
- photosynthate from leaves to
roots, shoots, meristems
- living at maturity
- no secondary cell walls
3. Evolutionary Sequence Observed in WaterConducting Cells
First vascular tissue
Simple waterconducting cells
Tracheids
Vessel elements
Ends have gaps
in secondary
cell wall (inside)
Primary wall
(with cellulose)
Primary wall
(with cellulose)
Lignin
Little structural
support. Found in
fossils and presentday mosses
Primary wall
(with cellulose)
Primary wall
(with cellulose)
Secondary wall
(with lignin)
Secondary wall
(with lignin)
Some structural
support. Found
in fossils
Increased structural
support. Found in
all vascular plants
Ends have gaps
through primary and
secondary cell walls
Found in gnetophytes
and angiosperms
7
4. Secondary growth
B. Fertilization without water
1.pollen and heterospory
a. In Gymnosperms
b. (lateral meristem - draw)
29.14d
Conifer life cycle
Co-evolution with animals
2. Flowers - more efficient fertilization (pollination)
Stamen = microsporangia
Ovule = megasporangium plus
integuments
Carpel = stigma + style + ovary
Petals and sepals = modified
leaves, attract pollinators
C&R, 30.13
Many crops depend on natural pollinators
Darwin’s Hawk Moth
http://www.pbs.org/wnet/nature/bestofnature/video.html
US Postal Service
http://www.berkeley.edu/news/media/releases/2006/10/25_pollinator.shtml
http://encarta.msn.com/media_461530192_761578331_-1_1/Darwin's_Hawk_Moth.html
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C. New mode of dispersing progeny
1. Seeds
Seed formation
Incorrect color in “c” - should be
blue for food supply, which is
haploid (megagametophyte).
C&R, Fig. 30.2
29.14d
Conifer life cycle
2. Fruits - more efficient dispersal
Fruits - different kinds
Wind-dispersed
Animal dispersed - eaten
Pine seed
Animal dispersed - riding
Coevolution with animals
30.20, 30.25
C&R, 30.15
Water-dispersed
2. Bryophyte life
cycle and
structure
3. Angiosperm life cycle
a. ovule inside carpel
b. smaller g’phyte
c. Double fert:
endosperm - 3n
d. After fert:
Ovule Æ seed
Ovary wall Æ fruit
1. G’phyte vs. s’phyte
2. Archegonia and
antheridia
3. Water for fert.
4. Embryo on g’phyte
5. Spores for dispersal
6. Roots and leaves?
Fig. 30.17a
9