chapter 29 plant diversity: how plants colonized land
TRANSCRIPT
Chapter 29
Plant Diversity:How plants colonized land
Plant Origins
Ch
loro
ph
yta
Pla
nta
e
Ancestral eukaryote
Rh
od
op
hyt
a
Fu
ng
i
Dip
lom
on
ad
ida
Par
aba
sal
a
Eu
gle
no
zoa
Alveolata Stramenopila Ce
rco
zoa
Ra
dio
lari
a
Amoebozoa An
ima
lia
Ch
oan
ofl
ag
ella
tes
Figure 28.4
See Fig. 29.7
Land plants evolved from
Charophyceans (multicellular,
eukaryotic, green-algae protists)
Land plants
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
See Fig. 29.7
Land plants evolved from
Charophyceans (multicellular,
eukaryotic, green-algae protists)
Chara (a Charophycean
pond alga)
Land plants
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
See Fig. 29.7
Land plants
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
The evidence consists of many
derived homologies of cellular micro-
structure and biochemistry (DNA,
chlorophyll, etc.)
Evolutionary innovations:
Colonization of land by the first bryophytes
See Fig. 29.7
Bryophytes(nonvascular plants)
Land plants
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
Evolutionary innovations:
Advent of a vascular system with the origin of vascular plants
See Fig. 29.7
Bryophytes(nonvascular plants)
Vascular plants
Land plants
Origin of vascular plants (about 420 mya)
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
Seedless vascular plants
Evolutionary innovations:
Origin of seeds (embryo packaged with a supply of nutrients inside a protective coat)
See Fig. 29.7
Bryophytes(nonvascular plants) Seedless vascular plants Seed plants
Vascular plants
Land plants
Origin of seed plants(about 360 mya)
Origin of vascular plants (about 420 mya)
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
Evolutionary innovations:
Evolution of flowers (seeds develop inside chambers called ovaries, which originate in flowers that mature into fruits)
See Fig. 29.7
Bryophytes(nonvascular plants) Seedless vascular plants Seed plants
Vascular plants
Land plants
Origin of seed plants(about 360 mya)
Origin of vascular plants (about 420 mya)
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
Evolutionary innovations:
Alternation of generations
See Fig. 29.7
Bryophytes(nonvascular plants) Seedless vascular plants Seed plants
Vascular plants
Land plants
Origin of seed plants(about 360 mya)
Origin of vascular plants (about 420 mya)
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
Review of chromosome number
• A diploid nucleus (2n) has two of each kind of chromosome
• A haploid nucleus (n) has only one of each kind of chromosome
Human chromosomes from a diploid cell
No alternation of generations
Animal Life Cycle:
Diploid phase is dominant
See Fig. 13.5
No alternation of generations
Animal Life Cycle:
Diploid phase is dominant
See Fig. 13.6
Key
Meiosis Fertilization
Haploid
Diploid
n
n
n
2n 2n
Mitosis
ZygoteDiploid multicellular
organism
Gametes
Haploid
No alternation of generations
Fungal Life Cycle (shared by some protists):
Haploid phase is dominant
See Fig. 13.6
Meiosis Plasmogamy & Karyogamy
n
2n
Gametesor
hyphae
Key
Diploid
MitosisMitosisn
nn
n
Zygote-like cell
Haploid multicellular organism
Spores
Haploid
See Fig. 13.6
Meiosis Fertilization
n
2n
Zygote
Diploid multicellular
organism (sporophyte)
Gametes
Key
Diploid
Mitosis
Alternation of generations
Plant Life Cycle (shared by some algae):
2n
nn
n
n
Haploid multicellular organism (gametophyte)
MitosisMitosis
Spores
Haploid or diploid phase is dominant, depending on the lineage
Haploid
See Fig. 13.6
Meiosis Fertilization
n
2n
Zygote
Diploid multicellular
organism (sporophyte)
Gametes
Key
Diploid
Mitosis
Plant Life Cycle (shared by some algae):
2n
nn
n
n
Haploid multicellular organism (gametophyte)
MitosisMitosis
Spores
Spore = reproductive cell that can develop into a new organism
Haploid
See Fig. 13.6
Meiosis Fertilization
n
2n
Zygote
Diploid multicellular
organism (sporophyte)
Gametes
Key
Diploid
Mitosis
Plant Life Cycle (shared by some algae):
2n
nn
n
n
Haploid multicellular organism (gametophyte)
MitosisMitosis
Spores
Gamete = reproductive cell that must fuse with another gamete
Fertili-zation
Meiosis occurs in specialized
cells to produce spores
Mitosis results in gametophyte
growth
Mitosis occurs in specialized
cells to produce gametes
Mitosis results in sporophyte growth
Alternation of generations
If humans had alternation of generations
Further Adaptations of Land Plants
Apical meristems
Shoot Root
See Fig. 29.5
Further Adaptations of Land Plants
Multicellular, dependent embryos with placental transfer cells
Embryo
Maternal tissue
See Fig. 29.5
Further Adaptations of Land Plants
The spore mother cells of diploid sporangia produce protected (walled) haploid spores
SporeSporangium
See Fig. 29.5
Further Adaptations of Land Plants
Multicelluar, haploid gametangia produce gametes (in all but angiosperms)
Archegonium: female gametangium
Egg
Archegonium
See Fig. 29.5
Further Adaptations of Land Plants
Multicelluar, haploid gametangia produce gametes (in all but angiosperms)
Antheridium: male gametangium
Sperm
Antheridium
See Fig. 29.5
Further Adaptations of Land Plants
Characters for conserving water
Waxy cuticle coating the epidermis
Further Adaptations of Land Plants
Characters for moving water
Lignified vascular tissues (found in all but bryophytes)
Lignin
Further Adaptations of Land Plants
Characters for moving water
Phloem and xylem
I. Non-vascular
Plants
(Bryophytes)
See Fig. 29.7
Dominant plants on Earth through the first 100 million years of land plants’ existence
Bryophytes(nonvascular plants)
Land plants
Origin of seed plants(about 360 mya)
Origin of vascular plants (about 420 mya)
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
I. Non-vascular
Plants
(Bryophytes)
II. Vascular Plants
A. Seedless
See Fig. 29.7
Dominant plants in Carboni-ferous, i.e., today’s fossil fuels
Bryophytes(nonvascular plants) Seedless vascular plants
Vascular plants
Land plants
Origin of seed plants(about 360 mya)
Origin of vascular plants (about 420 mya)
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
I. Non-vascular
Plants
(Bryophytes)
II. Vascular Plants
A. Seedless
B. Seed Plants
See Fig. 29.7
Dominant plants on Earth today
Bryophytes(nonvascular plants) Seedless vascular plants Seed plants
Vascular plants
Land plants
Origin of seed plants(about 360 mya)
Origin of vascular plants (about 420 mya)
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
I. Non-vascular
Plants
(Bryophytes)
II. Vascular Plants
A. Seedless
B. Seed Plants
i. Gymno-
sperms
ii. Angio-
spermsSee Fig. 29.7
Bryophytes(nonvascular plants) Seedless vascular plants Seed plants
Vascular plants
Land plants
Origin of seed plants(about 360 mya)
Origin of vascular plants (about 420 mya)
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
Bryophytes
Gametophyte dominant;
sporophyte dependent;
gametophyte independent
See Fig. 29.8
Bryophytes
MeiosisFertilization
KeyHaploidDiploid
Male gametophyte
Female gametophyte
Gameto-phytes produce gametes by mitosis
Antheridia
Archegonia
Sperm (flagellated)
Egg
See Fig. 29.8
Bryophytes
MeiosisFertilization
KeyHaploidDiploid
Male gametophyte
Female gametophyte
Antheridia
Archegonia
Egg
Zygote
A zygote begins the sporo-phyte generation
Mature sporo-phytes produce spores by meiosis See Fig. 29.8
Sporophytes
Spores
Sperm (flagellated)
Sporangium
Bryophytes
Moss gametophytes and sporophytes
Bryophytes
Thin structure allows distribution of materials without vascular system
Rhizoids anchor, but do not play a primary role in water and nutrient uptake
Phylum Hepatophyta - liverworts
P. Anthocerophyta hornworts
P. Bryophyta mosses
Bryophytes
Ball or Spanish “moss” – an Angiosperm
Bryophytes
Seedless vascular plants
Sporophyte dominant; sporophyte initially
dependent; gametophyte independent
See Fig. 29.12
Seedless vascular plants
Meiosis
Fertilization
Key
Haploid
Diploid
Gametophyte
Antheridium
Egg
Sperm (flagellated)
See Fig. 29.12
Archegonium
Gametophytes produce gametes by mitosis
Fern prothallus = gametophyte
Seedless vascular plants
Gametophytes produce gametes by mitosis
Seedless vascular plants
Meiosis
Fertilization
Key
Haploid
Diploid
Gametophyte
Antheridium
Egg
Sperm (flagellated)
See Fig. 29.12
Archegonium
Gametophytes produce gametes by mitosis
Seedless vascular plants
Meiosis
Fertilization
Key
Haploid
Diploid
Gametophyte
Antheridium
Egg
Zygote
Mature sporophytes
Sperm (flagellated)
See Fig. 29.12
Archegonium
Youngsporophyte
Gametophyte
A zygote begins the sporophyte generation
Seedless vascular plants
Meiosis
Fertilization
Key
Haploid
Diploid
Gametophyte
Antheridium
Egg
Zygote
Mature sporophytes
Spores
Sperm (flagellated)
See Fig. 29.12
Archegonium
Youngsporophyte
Gametophyte
Sporangium
Sorus
Sporophyll
Mature sporophytes produce spores by meiosis
Sori = clusters of sporangia
Seedless vascular plants
Seedless vascular plants
See diagram on pg. 586
Homosporous spore production (most seedless vascular plants)
Heterosporous spore production (some seedless vascular plants; all seed plants)
Sporangium insporophyll
(2n)
Single type of spore
(n)
Bisexual gametophyte
Eggs
Sperm
Seedless vascular plants
Meiosis
Fertilization
Key
Haploid
Diploid
Gametophyte
Antheridium
Egg
Zygote
Mature sporophytes
Spores
Sperm (flagellated)
See Fig. 29.12
Archegonium
Youngsporophyte
Gametophyte
Sporangium
Sorus
Sporophyll
Seedless vascular plants
See diagram on pg. 586
Homosporous spore production (most seedless vascular plants)
Heterosporous spore production (some seedless vascular plants; all seed plants)
Sporangium insporophyll
(2n)
Single type of spore
(n)
Bisexual gametophyte
Eggs
Sperm
Megasporangiumin megasporophyll
(2n)
Megaspore(n)
Female Gametophyte
(n)
Microsporangium in microsporophyll
(2n)
Microspore(n)
Male Gametophyte
(n)
Eggs(n)
Sperm(n)
Evolution of:
Leaves
(principal photosynthetic organs of vascular plants)
Seedless vascular plants
Evolution of:
Roots
(principal organs that anchor vascular plants and absorb water & nutrients)
Seedless vascular plants
Evolution of:
Vascular tissues
(conduits that distribute water & nutrients within vascular plants)
Seedless vascular plants
Phylum Lycophyta
“Club mosses”
Seedless vascular plants
Phylum Pterophyta
Horsetails
E.g., Equisetum
Seedless vascular plants
Strobilus – a group of sporophylls forming a cone
Phylum Pterophyta
Horsetails
Seedless vascular plants
Phylum Pterophyta
Whisk ferns
Seedless vascular plants
Phylum Pterophyta
Ferns
Terrestrial species are found on the ground
Seedless vascular plants
Phylum Pterophyta
Ferns
Resurrection fern is an epiphytic species, i.e., it grows
on other plants
Seedless vascular plants
Seedless vascular plants
A modern community
Seedless vascular plants
A diorama of an ancient community
Seedless vascular plants
A fossil stump of a seedless vascular plant
I. Non-vascular
Plants
(Bryophytes)
II. Vascular Plants
A. Seedless
B. Seed Plants
i. Gymno-
sperms
ii. Angio-
spermsSee Fig. 29.7
Bryophytes(nonvascular plants) Seedless vascular plants Seed plants
Vascular plants
Land plants
Origin of seed plants(about 360 mya)
Origin of vascular plants (about 420 mya)
Origin of land plants(about 475 mya)
Ancestralgreen alga
Ch
aro
ph
ycea
ns
Liv
erw
ort
s
Ho
rnw
ort
s
Mo
sses
Lyc
op
hyt
es(c
lub
mo
sses
etc
.)
Pte
rop
hyt
e (f
ern
s, h
ors
etai
ls,
wh
isk
fern
)
Gym
no
sper
ms
An
gio
sper
ms
Hashed lines indicate uncertainties
The Life Cycle of Animals – Illustrated for Humans
Generation 1
Multicellular individuals;Diploid (2n) cells
Unicellular gametes;
Haploid (1n) cells
Generation 2
Specialized cells undergo meiosis
to produce gametes
Gametes fuse during fertilization
to become a zygote
AY
aX
AaXY
From the single-celled zygote stage onward, cells undergo mitosis to increase
the number of cells in the maturing individual.
Unicellularzygote;
Diploid (2n)cell
Muticellular individuals;Diploid (2n) cells
AX
aX
AAXY
AaXX
AAXX
AaXY
Gen. 3
AaXX
The Life Cycle of Fungi – Illustrated for Bread Mold
Several generations
Diploid (2n) zygote
Several generations
Haploid (1n) cells of hyphae
Multiple rounds of asexual reproduction
possible; all cell divisions occur by
mitosis.
Brief inter-generationalzygote stage
Haploid (1n) cells of hyphae
Zygotic meiosis
Multiple rounds of asexual reproduction
possible; all cell divisions occur by
mitosis.
Multiple rounds of asexual reproduction
possible; all cell divisions occur by
mitosis.
Multiple rounds of asexual reproduction
possible; all cell divisions occur by
mitosis.
Fusion of compatible hyphae to form a zygote
Aa
+-a
-
Haploid (1n) spore
A+
a-
a-
a+
The Life Cycle of Plants (Alternation of Generations) – Illustrated for a Dioecious Flower
Generation 1
Multicellular sporophyte
Unicellular spores
Generation 2
Specialized cells undergo meiosis to produce spores
Gametes fuse during fertilization
to become a zygote
aB
AaBb
Single-celled spores undergo mitosis to increase the number of cells in the
maturing gametophyte. Mature gametophyte produces gametes
by mitosis
Multicellular gametophyte
Ab
Haploid (1n) cells
Ab
aB
Unicellulargametes
Generation 3
Diploid (2n) cells
Multicellular sporophyte
Diploid (2n) cells
Unicellular spores of
gametophyte
Haploid (1n) cells
Pollengrain
Embryo sac
Gen. 4
AAbb
AaBb
AaBb
Unicellularzygote
aaBB
Specialized cells undergo meiosis to produce spores
Ab
aB