Download xCh 16 plants Sp11

Characteristics of plants
Ch 16
Evolution of Plants
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Eukaryotes (nucleus, internal organelles)
Multicellular
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Photosynthetic
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Make organic molecules by photosynthesis
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Autotrophs: feed themselves (and animals)
The dominant organisms on land
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Plant evolution:
Adapting to Living on Land
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Plants evolved from
green algae
Both
 Perform photosynthesis
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Store excess
carbohydrates as starch
Plant evolution:
Adapting to Living on Land
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To live on land, plants evolved
specialized structures
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Highlights of Plant Evolution
1.
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3.
4.
Roots
Support
Cuticle (waxy covering)
Leaves
Methods of reproducing on land
Terrestrial adaptations:
Conserving water
Adaptations to
living on land
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2.
Over 263,000 species of plants
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Water
conservation
Support
Specialized
structures to
protect gametes
and embryos
Vascular tissue
Seeds
Flowers
The waxy cuticle helps the
plant retain water
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Specialized pores called
stomata (singular, stoma)
allow gas exchange
through the cuticle
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Green
algae
A stoma
the cuticle prevents water
loss to the air
They open and close
Terrestrial adaptations:
Vascular tissue
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How do plants
transport water and
food between the roots
and leaves?
A system of tubes
(veins) conducts water
and food throughout
the plant
Terrestrial adaptations:
Reproduction
How do plants protect their
gametes and embryos
from drying out?
Developed protective
structures called
gametangia.
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Sexual reproduction on land –
a special challenge
Evolution of plants
Plants can’t move – how do they pass
gametes from one plant to another?
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The embryo develops in a
moist chamber which keeps
it from dehydrating.
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Key innovations
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early plants used spores for reproduction
later pollen evolved
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transferred by wind or insects
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Bryophytes:
simple, nonvascular plants
Mosses
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Evolved first
No vascular system
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Lack true roots and leaves
Bryophytes
Ferns
Gymnosperms
Angiosperms
The most familiar bryophytes
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Terrestrial
adaptations
Vascular tissue
Seeds
Flowers and fruits
The many plants in a mat of
moss hold each other up
Need water to reproduce
Key terrestrial adaptations:
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A waxy cuticle helps prevent
dehydration
Embryos develop within the
gametangia
The evolution of vascular
tissue
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Vascular tissue –
specialized cells that
form a network
throughout a plant
 Xylem–conducts water
Evolution of Vascular Tissue
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Phloem–conducts
sugars made in the
leaves throughout the
plant
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Can grow tall due to
vascular tissue
Reproduce with spores
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from the roots to the
leaves
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Ferns
Can develop into new
organism without fusing
with another cell
Seedless vascular
plants
“Fiddlehead”
(young leaves
ready to unfurl)
Seeds –
Basic structure of seeds
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a key adaptation to living on land
A drought-resistant
protective cover
Embryo
Food for the developing
embryo, endosperm
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Improve the dispersal of plants into
new habitats
Permit plants to postpone
development until conditions are
favorable
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Improve germination
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In some seeds, food is
stored in leaf-like
structures called
cotyledons
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Evolution of Seed Plants
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Plant develops with warm temperature,
rainfall
Provide food for the young plant
Seed plants are divided into
two groups
Seed plants produce two kinds of
gametophytes
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Provide dormancy
pollen grains = male
eggs within ovules = female
There is no need for water in the fertilization
process
The plant is pollinated by the wind, insects,
birds, or other agents
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The pollen grain cracks open and sprouts a pollen
tube, which transfers the male gametophyte
directly to the egg
Bryophytes
Ferns
Seeds
Gymnosperms
Seeds produced in cones
Angiosperms
Flowers bear seeds within
the ovary
Gymnosperms
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The life cycle of conifers
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Female
cones
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Male
cones
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Have a vascular system
and “naked” seeds
but no flowers
Conifers form two types of
cones
 Seed-bearing cones contain
the female gametophytes
Conifers are an example
of gymnosperms
Seeds are produced in
cones where pollination
occurs
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Smaller male cones produce
pollen (male gametophytes)
Pollen grains travel by wind to
the seed-bearing cones
Plant reproduction: pine tree 2:42
http://www.youtube.com/watch?v=DzP7xEDH
ZKc&feature=channel
Angiosperms:
Angiosperms
or Flowering plants
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Bryophytes
Flowers are reproductive
structures
Ferns
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Gymnosperms
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Angiosperms
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90% of all living plant species are angiosperms
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Why so successful?
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contain pollen (“male”) and
eggs (“female”)
Ovule is completely
enclosed by the ovary
Flowers improve the
efficiency of mating
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attract pollinators – insects,
butterflies, birds, etc
Evolution of the flower
What do flowers have in
common?
Why are there different kinds of
flowers?
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Sepals – enclose the flower
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Petals – attract pollinators
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Stamens – “male” parts that
before it opens
produce pollen
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the anther at the tip of the stamen
contains pollen
Carpel – the “female” part of the
flower that produces the egg
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the ovules are enclosed in the
ovary
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the stigma receives pollen
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Pollination, pollination, pollination
Flowers vary in size, shape and color so that
they can be identified by a particular pollinator
Insects specialize in pollinating particular
kinds of flowers
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This improves the likelihood that the pollen will be
carried to a flower of the same species
Wind pollination
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Insect pollination
Many plants, such as
grass, weeds and even
large pine trees, rely on
the wind for pollination.
The pollen is small and
light, allowing it to be
blown by the wind.
The pollen lands on
other plants a fertilizes
them.
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The pollen grain produces 2 sperm cells
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one fertilizes the egg, develops into the embryo
the other fuses with the central cell, producing endosperm
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Evolution of Fruit
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Another key advance in
angiosperms
Fruit
 Forms from the ovary,
contains seeds
 Helps protect the seed
and improves seed
dispersal
 Is a major food source for
animals
common insect
pollinator
As a bee gathers nectar
from a flower, tiny
grains of pollen stick to
its hairy legs and body.
When the bee flies to
another flower, the
pollen on its legs and
body brushes off to help
fertilize the flower.
Double fertilization –
only in angiosperms
The life cycle of an angiosperm
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Bees are the most
a highly nutritious tissue that is food for the embryo
Seed dispersal
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Fruits are specialized
for dispersing seeds
Common methods of
dispersal
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Wind
Water
Attaching to animals
Fleshy fruits are eaten
The seed germinates
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Plants and Agriculture
Germination –
resumption of the
seed’s growth and
development
Triggered by water and
temperature
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Gymnosperms
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Angiosperms
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wheat
supply most of our
lumber and paper
Provide nearly all our
food
Supply fiber,
medications,
perfumes, and
decoration
cotton
Kingdom Fungi
FUNGI
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Eukaryotes
Most are multicellular
Heterotrophs
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They digest their food
externally and absorb the
nutrients from the
environment
Fungi are extremely
important to
ecosystems
because they
decompose and
recycle organic
materials
Discovery Channel 16-22 Fungi
Structure of fungi
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Reproductive
structure
Hyphae
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Sporeproducing
structures
Bodies are constructed of
hyphae
Mushrooms are reproductive
structures that extend from
the underground mycelium
Lichens:
another symbiotic relationship
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Mycelium
Symbiotic associations of
fungi and algae
The photosynthetic algae
feed the fungi
The fungal mycelium
provides a habitat for the
algae, helps them absorb
water and minerals
The merger is so complete
that lichens are named as
species