Transcript Photosynthesis

BIOLOGY
Chapter 23: pp. 408 - 432
10th Edition
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seed cones
seed cones
pollen cones
a. A northern coniferous forest of evergreen trees
b. Cones of lodgepole pine, Pinus contorta
Sylvia S. Mader
Plant Evolution and
Diversity
c. Fleshy seed cones of juniper, Juniperus
a: © Corbis Royalty Free; b: © Walt Anderson/Visuals Unlimited; c: © The McGraw Hill Companies, Inc./Evelyn Jo Johnson, photographer
PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor
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1
Evolutionary History of Plants
Plants are multicellular, photosynthetic
eukaryotes.
 Plants evolution is marked by adaptations
to a land existence.
 A land environment does offer certain
advantages.

Plentiful light for photosynthesis
 Carbon dioxide is present in higher
concentrations and diffuses more readily in air
than in water.

3
Evolutionary History of Plants

A land environment does offer certain
advantages

Constant threat of desiccation (drying out).
Protect all phases of reproduction (sperm, egg,
embryo) from drying out
 Seed plants disperse their embryos within the seed,
which provides the embryo with food within a
protective seed coat.


The water environment provides
plentiful water.
 support for the body of the plant.

4
• Nonvascular Plants- have small reduced leaves, no vascular
tissue(veins to carry water) no true roots, and reproduce by spores or
flagellated cells that travel through water.
– Bryophyta (mosses)
• Vascular Plants- have true roots, stems, and leaves with vascular
tissue. Xylem- water and minerals. Phloem- transports
carbohydrates
– seedless plants
• club moss
• Ferns
– seed plants
• Gymnosperms - naked seeds
– Conifer- needle or scale leaf, cones
• Angiosperms - flowering plants
» Monocots- parallel veins, petals in 3‘s
PLANT
OUTLINE
Non-Vascular
– Water movement by
osmosis
– Solutes move by
diffusion
– Plants not very large,
all parts must be near
their water source
vs.
Vascular
–Water and solutes moved
through special cells called
xylem
–Sugar transported by special
cells called phloem
–Plants can be 300’ tall and
parts can be distant from water
source
Alternation of Generations

Life cycle involves alternation of generations



Sporophyte (2n):



Multicellular 1n individuals (gametophytes) produce
multicellular 2n individuals (sporophytes)
Multicellular 2n individuals (sporophytes) produce
multicellular 1n individuals (gametophytes)
Multicellular individual that produces spores by
meiosis
Spore is haploid cell that will become the gametophyte
Gametophyte (1n):



Multicellular individual that produces gametes
Gametes fuse in fertilization to form zygote
Zygote is a diploid cell that will become the sporophyte
9
Alternation of Generations
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sporophyte
(2n)
sporangium (2n)
zygote (2n)
FERTILIZATION
diploid (2n)
MEIOSIS
haploid (n)
spore (n)
(n)
(n)
gametes
gametophyte
(n)
10
Alternation of Generations

Appearance of generations varies widely

In ferns, female portions are archegonia and are
fertilized by flagellated sperm

In angiosperm, female gametophyte (embryo sac),
consists of an ovule


Following fertilization, ovule becomes seed
In seed plants, pollen grains are mature sperm-bearing
male gametophytes
11
Reduction in the Size of the
Gametophyte
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spores
G
a
m
e
t
o
p
h
y
t
e
seed
seed
spores
roots
roots
rhizoids
roots
rhizoids
(n)
Moss
Fern
S
p
o
r
o
p
h
y
t
e
(2n)
Gymnosperm
Angiosperm
12
Nonvascular Plants:
Bryophytes

Nonvascular plants (bryophytes)

Lack specialized means of transporting water and
organic nutrients

Do not have true roots, stems, and leaves

Gametophyte is dominant generation

Produces eggs in archegonia

Produces flagellated sperm in antheridia

Sperm swim to egg in film of water to make zygote
15

Hornworts have small
sporophytes that carry on
photosynthesis (shown in
diagram to the right)

Liverworts have either
flattened thallus or leafy
appearance

Nonvascular
Plants
sporophyte
Mosses usually have a
leafy shoot, although
some are secondarily
flattened

Can reproduce
asexually by
fragmentation
gametophyte
B. Runk/S. Schoenberger/Grant Heilman Photography

Dependent sporophyte
consists of foot, stalk,
and sporangium
16
Alternation of Generations:
Nonvascular Plants
12
Vascular Plants





Dominate the natural landscape
Xylem conducts water and dissolved minerals up
from roots
Phloem conducts sucrose and other organic
compounds throughout the plant
Lignin strengthens walls of conducting cells in
xylem
All seed plants are heterosporous and have male
and female gametophytes

Seeds disperse offspring
20
Fern Life Cycle
Gymnosperms

Largest group of gymnosperms = conifers.
examples of conifers: pine, spruce, cedar,
redwood

naked seeds (no fruit)

needle like leaves

most are evergreens

well adapted to hot summers and cold winters
35
Conifer Life
Cycle
Angiosperms




Flowering plants
seeds enclosed in fruit
“hardwood” trees....maple, oak
Two classes of flowering plants
 Monocotyledones (Monocots)
 Dicotyledones (Dicots)
45
Angiosperms – Flowers & Fruits
•
Peduncle (flower stalk) expands at tip
into a receptacle
•
Bears sepals, petals, stamens,
and carpels, all attached to
receptacle in whorls
•
Calyx (collection of sepals) protect
flower bud before it opens
Carpel
Stigma
Anther
Stamen
•
Corolla (collection of petals)
•
Each stamen consists of an anther and
a filament (stalk)
•
Carpel has three major regions
Style
Ovary
Filament
Petal
– Ovary - Swollen base
•
Sepal
Fruit
– Style - Elevates stigma
– Stigma - Sticky receptor of pollen
grains
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Receptacle
Ovule
Generalized Flower
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anther
stigma
filament
style
pollen
tube
ovary
stamens
ovule
carpel
receptacle
petals (corolla)
sepals (calyx)
51
Flowering
Plant Life
Cycle
Flowers and Diversification

Wind-pollinated flowers are usually not showy

Bird-pollinated flowers are often colorful

Night-blooming flowers attract nocturnal
mammals or insects


Usually white or cream-colored
Fruits of flowers protect and aid in dispersal

Utilize wind, gravity, water, and animals for dispersal
53
Other Terrestrial Adaptations

Vascular tissue transports water and
nutrients to the body of the plant

Cuticle provides an effective barrier to
water loss

Stomata bordered by guard cells that
regulate opening, and thus water loss
13
Leaf Adaptation
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cuticle
a. Stained photomicrograph
of a leaf cross section
Plant leaves have a
Cuticle and stomata
Stomata
400 x
b. Falsely coloured scanning
Electron micrograph of leaf
surface
(Left): © Kingsley Stern; (Right): © Andrew Syred/SPL /Photo Researchers, Inc.
14
• Nonvascular Plants- have small reduced leaves, no vascular
tissue(veins to carry water) no true roots, and reproduce by spores or
flagellated cells that travel through water.
– Bryophyta (mosses)
• Vascular Plants- have true roots, stems, and leaves with vascular
tissue. Xylem- water and minerals. Phloem- transports
carbohydrates
– seedless plants
• club moss
• Ferns
– seed plants
• Gymnosperms - naked seeds
– Conifer- needle or scale leaf, cones
• Angiosperms - flowering plants
» Monocots- parallel veins, petals in 3‘s
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