Download Chapters 29

Chapters 29 -30
Plants
There are many different species of plants
270,000+ species of plants have been described so
far by botanists
Why study plants?
Provide the Oxygen we breathe
Plants provide the Ozone UV screen
Food
Fossil Fuels
Essential oils
Wood and paper
Jobs
Medicine
Decoration
Habitat
Fibers
"The Importance of Plants“
reference: Chapter 29
Plants As Food "of the more than 350,000 plant species, people use
at least 10,000 species for food."
• FOOD CROPS
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cereals
root crops
legumes
fruits, vegetables and nuts
spices, herbs, and flavorings
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NONFOOD USES OF PLANTS
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PLANT ECOLOGY
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medicinal- quinine. aspirin, taxol, echinacea, etc.
clothing and fabric dyes
fuels
anti-erosion
fertilizers- crop rotation
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food chain - producers
oxygen supply
plant-animal interactions
harmful plants
Photosynthesis
The process in which
plants use H2O, CO2, and
light energy to make food
(sugars)
O2 is released!
The most important chemical reaction in the world???
Plant Evolution and Classification
reference: chapter 30
• 1st land plants----> simple structure; probably
evolved from green algae (Chlorophytes)
• Advantages to living on land:
light more available
CO2 more available
at the time = no other competing life forms (no
organisms living on land until about 430 mya)
• Problems with living on land- must evolve
protective features to live on land
preventing water loss
reproducing by seeds and spores
transporting materials throughout body
How are plants classified?
Botanists group plants to make it easier to study
and learn from them
Classified based on their traits
Tissue structure
Seed Structure
Size
Reproductive characteristics
How are plants classified?
Vascular- plants that
have tube-like cells
for transport of
materials
Non-vascular- no
tube-like cells; absorb
materials through
contact
What traits do all plants have in common?
What traits do all plants have in
common?
All plants:
•Are multicellular
•Cells are eukaryotic
•Chlorophyll
containing chloroplasts
•Stiff cell wall
(cellulose)
BRYOPHYTES: Non-vascular plants
Plants without vascular
tissue; cannot transport
materials up/down
 No true roots (hair-like
projections called
“rhizoids”)
Mosses
 Non-vascular plants get
H2O by osmosis
 Stems and leaves grow
close to the ground why?
Liverworts
 Usually grow in damp,
shaded environments why?
gametes produced in sex
structures: archegonia
(female) and antheridia
(male)
spores produced in sacs
called "sporangia"
(contained in capsules at
the plant's tip)
Gametophyte is the
dominant stage in
bryophytes
Alternation of Generations in
Plants
Moss Life Cycle:
http://www.su
manasinc.com/
webcontent/ani
mations/conten
t/moss.html
Significance of mosses and liverworts?
Food/shelter for small animals and insects
Hold soil into place (reduce erosion)
Used as an nesting material
Ecologically important “pioneer”
organisms: breakdown of rocks into soil
Increase amount of water held: peat moss
& houseplants
Peat moss is a fuel
Vascular plants
 Vascular plants have true roots, stems, and
leaves
Xylem- carry water and dissolved nutrients from
roots to leaves
 Phloem- carry sugars made from
photosynthesis from leaves to all parts of the
plant
Vascular plants
What advantages do vascular plants have?
TRACHEOPHYTES: the
vascular plants
• Have true leaves, roots, stems
• Have support: lignins and fibrous materials
• Have a true conducting system for water, food,
and minerals
– xylem- conducts water and ions from roots to
leaves
• The conducting elements of xylem are called
TRACHEIDS and VESSEL MEMBERS
– phloem- carries dissolved sugar and other
products of photosynthesis from the leaves to
the nonphotosynthetic cells of the plant.
• The conducting elements of phloem are
called SIEVE CELLS or SIEVE-TUBE
MEMBERS
Earliest Vascular Plants: Pterophyta,
Sphenophyta, etc.
 Ancient ancestors of the plant world; have been
around for ~335 my
Includes ferns, horsetails, club mosses
Reproduces by spores, rather than seeds
 Grow taller than mosses and liverworts because of
the vascular system
 one stage of life does not have a vascular system
(rhizoids) so ferns like moist, shady places to live
 over 12,000 species of ferns (~8,000 tropical)
The Seed Plants
•~300 myo; includes most
"modern" plants
•have a dominant sporophyte
stage
•reproduce using pollen (sperm)
traveling to egg (ovum) on
cones or flowers, which results
in SEEDS
What are seeds?
Part of a plant that contains a
new, young plant + stored food
Why does any embryo have
stored food?
Uses of seeds
pesticides
Milkweed seed
extracts used to
control roundworm
pops. in crops
Industrial
Castor oil is used to
lubricate aircrafts
and also as a
component in
shatterproof glass
Food!
3,500 uses for corn
alone!
spices
cosmetics
Grape seed extract
Neem oil
Medicine
Flax seed extract
Grapefruit seed extract
~herbal medicines
decoration
THE VASCULAR SEED PLANTS2 groups dominant today
• Gymnosperms "naked seed"; ~350 myo,
about 700 species today
• Angiosperms "flowering plants"; ~135 myo,
about 240,000 species today
Gymnosperms:
• do not have flowers as reproductive
structures
• Division Cycadophyta: cycads
• Division Ginkgophyta: ginkgos
• Division Coniferophyta: cone-bearing
trees, evergreens, pines; have reducedsized leaves = needles (water
conservation)
• Division Gnetophyta: some desert
plants, like Ephedra
Conifers
cone-bearing plants
 most evergreens
 found mainly in Northern areas of
the world
 sheds leaves like a dog- not all at
once!
In what part of NJ would you find a lot of
conifers?
Conifers
Has anyone ever noticed that a pine tree has 2
different cones on it?
Female and Male Cones
Conifers
Some conifers do not have woody cones
Yews have red, fleshy cones that birds love to eat!
The birds spread the seeds via their digestive system
Conifers are important!
 Produce 50-75% of the world’s lumber & paper pulp
 Important to other animals for food and shelter (Northern
Spotted Owl)
 Turpentine (from sap)
 Taxol (cancer drug from Yew bark)
 Christmas trees
California redwoods..Sequoia
Yosemite National Park
The Angiosperms: Flowering plants
 Angiosperm (“closed seed”)
 Produce flowers and form fruit containing seeds
 More flowering plants than non-flowering plants (~230,000
flowering plants); Very successful! Reasons?
 Plants flower at different times of the year
Flowering plants- life cycle
Generalized life cycle of flowering plants
Flower Types
Rafflesia arnoldi
Wolffia angusta
Titan arum
Two classes of Angiosperms
• Monocots, Dicots
• "cotyledon" : the embryonic seed
leaf
Differences between
monocot/dicot species:
DICOTS:
-two embryonic seed
leaves
-Dicots contain vascular
bundles in the stem in the
form of a ring
-Leaves have a networklike venation in dicots (also
usually broad, wide leaves)
-Dicots have a taproot
system (main central root)
-Dicots have flowers in
groups of 4 or 5 petals
MONOCOTS:
-Single embryonic seed leaf
-Monocot leaves are tapered w/
parallel venation
-Monocots have a fibrous root system
(close to surface)
-Vascular bundles are scattered in a
monocot stem
-Monocots have flowers w/ groups of 3
petals
Difference between
monocot/dicot species: