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Plantae
Seed Plants
Vascular Plants
• Formation of vascular tissue
– Xylem (water)
– Phloem (food)
– True leaves, roots, and stems
• Lignin
• ____________ generation
dominate
Alternation of Generation
Alternation of Generation
• Sporophyte dependent on
gametophyte
– mosses
• Large sporophyte and small
independent gametophyte
– ferns
• Gametophyte dependent on
sporophyte
– seed plants
Why be Sporophyte
Dominant?
• Reduced mutations
– UV light harmful to DNA
– Diploid (2n) form copes better with
mutations
• two alleles
Why Retain Gametophyte
Generation?
• Ability to screen alleles
– doesn’t require a large amount of
energy
• Sporophyte embryos rely on some
gametophyte tissue
Seeds
• A seed is a sporophyte in
a package
– spores are only single cells
– packaged with food
• All seed plants are
_____________ (more
than one kind of spore)
– megasporangia
– microsporangia
From Ovule to Seed
Develops from megaspore
Whole structure
Embryo,
food supply,
protective
coat
Overview of Seed Plants
• Produce Seeds
– Can remain dormant for years
– Pollination replaces swimming sperm
• Gametophyte generation reduced
– Gymnosperms lack antheridium
– Angiosperms lack both archegonium
and antheridium
Phylogeny
Gymnosperms
(Naked Seed)
• Division:
• Division:
• Division:
• Division:
Cycadophyta
Ginkgophyta
Gnetophyta
Coniferophyta
Ginkgophyta
•
•
•
•
Ginkgo or Maidenhair Tree
Characteristic leaves
Only one species
Only ______ are planted
Cycadophyta
• Cycads
• Palm-like plants
– Sago Palms
• Leaves in cluster
at top of trunks
• True __________
Gnetophyta
• 3 Genera
• Ephedra
• Mormon Tea
– ____________
• raises heart rate
• raises blood
pressure
Coniferophyta
Coniferophyta
• Pine tree is the
sporophyte
generation
• Contains both male
and female cones
– Pollen (___________)
cones (low in tree)
• produces pollen
– Ovulate cones (high in
tree) with scales
• produces seeds
Pine Life Cycle
• No Antheridium (microsporangia)
produce pollen grain (4 cells)
– 2 prothallial cells
– 1 generative cell
» produces 2 sperm
– 1 tube cell
– __________ for dispersal
Pine Life Cycle
• Ovule in a ovulate cone
– integument (seed coat) (2n)
– megasporangia or nucellus (nutrition)
(2n)
– 4 _______________ from female
gametophyte (3 die)
• develops into female gametophyte
– archegonium with eggs (n)
Angiosperms
Angiosperm
Flower
• Sepals
• Petals
• Receptacle (part
of the stem)
• Stamen
– Anther
– Filament
• Carpel
– Stigma
– Style
– Ovary with ovule
Angiosperm Life Cycle
Angiosperm Life Cycle
• No Antheridium (microsporangia diploid)
• produce pollen grain
– 1 ___________ cell
» produces 2 sperm
– 1 tube cell
Angiosperm Life Cycle
• Ovule in Ovary
– megasporangia
– produces 4 megaspores (3 die)
• remaining one develops into female
gametophyte called the _____________
Angiosperm Life Cycle
• Embryo sac (Female
Gametophyte) consists of:
– 7 cells (eight nuclei) due to 3 mitotic
divisions
•3
•2
•2
•1
___________
polar nuclei (one cell)
__________
egg
Angiosperm Life Cycle
• Double fertilization
– one sperm unites with egg
– one sperm unites with polar nuclei
• develops into endosperm (3n)
• Fruit and Seed development
– ovule = seed
– ovary = fruit
Angiosperm Life Cycle
Cross Pollination
• Most flowers do not self-pollinate
– stamen and carpal may develop at
different times
– stamen and carpal may be arranged
in flower to avoid contact
Angiosperm Radiation
• Begins the Cenozoic era (65 mya)
• Most closely related to the
Gnetophyta
• __________
– the mutual influence of two species
on each other
– plants and animals (insects, birds,
bats)
Pollination
Dispersal
The Global Impact
• Transformed atmosphere
– reduced carbon dioxide
– cooled the earth
• Nonrenewable/Renewable resource
Plant Structure
And Growth
The Plant Body is
Composed of Cells and
Tissues
•Tissue systems (Like Organs)
–made up of tissues
•Made up of cells
Plant Tissue Systems
• ____________________
photosynthesis
storage
support
Vascular Tissue System
• ____________________
conduction
support
Dermal Tissue System
• ___________________
Covering
Dermal Tissue System
• Epidermis
– Single layer, tightly packed cells
– Complex Tissue – Does different
things in different areas (roots vs.
leaves)
– usually transparent
– secretes cuticle
Periderm
• ___________
–
– replaces epidermis in woody plants
– protection
Root System
• ____________
– Tap Root
– Lateral Roots
Shoot System
• ____________
– Stems
• Nodes (leaves
are attached)
• Internodes
– Leaves
• blades
• petioles
– Buds
Plant
Systems
• Terminal
(apical)
• Axillary
Plant Growth
Meristematic
• ______________
Tissue
–generates cells for new
growth (like stem cells in
animals)
•apical meristems
•lateral meristems
Apical Meristems
• increases length called primary
growth
Protoderm
–___________
- gives rise
to dermal tissue
Ground Meristem
–________________gives rise to ground tissue
–_____________ - gives
rise to vascular tissue
Lateral Meristems
• increases girth called secondary
growth
–__________________produces secondary xylem and
secondary phloem
Cork Cambium
–______________produces
cork (outer most layer of bark)
Pine Tree w/ 8 Cotyledons!
The Root System
• Functions
– anchor plant
– absorb minerals, water and
nutrients
– store food
• Systems
– ____________ - one large root
with smaller lateral roots (dicots)
Fibrous roots threadlike roots
– ____________(monocots)
Root Tissue
• Protoderm - gives rise to the
epidermis
• Ground Meristem
– Cortex (external to vascular
tissue)
• Procambium - gives rise to the
Stele (the vascular tissue of a
_______
root or stem)
– xylem and phloem
– may include pith (parenchyma
cells surrounded by vascular
tissue)
Dicot Root vs. Monocot
Xylem
(larger, in
red)
Endodermis
Phloem
(smaller,
greenish)
Pericycle – one layer IN
from endoderm, gives
rise to lateral roots
“Pith” – central core of
parenchyma cells
surrounded by xylem and
phloem
Modified Roots
• Food Storage
– carrots, sweet
potatoes, yams
• Water Storage
– pumpkin family
• Propagative
Roots
– cherries, pears
• Pnematophores
– mangroves
• Aerial Roots
– orchids
• Buttress Roots
– tropical trees
• Haustoria
– dodder
Shoot
System
Stems (Primary Growth)
• Protoderm - gives rise to the
epidermis
• Procambium - gives rise to the
stele
– xylem and phloem in vascular
bundles
•dicots - found in ring
•monocots - scattered
throughout
– includes “pith” in dicots
• Ground Meristem
– Cortex
____________
– stele (vascular tissue)
divided into strands in
stems and leaves
Sclerenchyma
cells
Phloem
Xylem
Dicot Stem Vs. Monocot (35.16)
Vascular Bundle
Ground Tissue
(Pith)
(Cortex)
How can you tell root from stem?
Stems (Secondary Growth)
• Occurs to increase girth
(thickness)
– Vascular Cambium
• produces secondary xylem and
secondary phloem
– Cork Cambium
• produces cork and phelloderm
(thin layer of parenchyma cells)
• together these structures are called
periderm (Cork Cambium, cork,
phelloderm)
Secondary Growth
Derivative
Vascular cambium
Secondary
Growth of
a Stem
• Pith
• Primary
Xylem
• Secondary
Xylem
(wood)
• Vascular
Cambium
Periderm
Secondary Growth of a
Stem (Inside to Outside)
• Secondary
Phloem
• Primary
Phloem
• Cortex
• Phelloderm
• Cork Cambium
• Cork (outer
layer of bark)
Older, inner layers
of 2° Xylem – no
longer transport
water
Younger, outer
layers of 2°
Xylem still
function in
transport
All tissue
outside
vascular
cambium
Missing cortex and phelloderm!
___________ (Early) growth
occurs more
quickly. Cells are large and thin
walled and have less strength.
Summerwood (Late) growth
occurs more slowly. Cells are
thicker, more dense, and stronger.
Modified Stems
• __________ - horizontal
stems above the ground
(strawberries)
• Rhizomes - horizontal
stems below the ground
(Irises)
• Tubers - swollen areas of
rhizomes or stolons
(Potatoes)
• Bulbs & Corms - vertical
shoots under ground
(onions, garlic w/ mod
storage leaves)
Cladophylls
• _____________
cactus pads
Leaf Structure
Leaves
• Epidermis
Stomata
– __________
- openings on
underside of leaf
– Guard Cells - surround stomata
– Cuticle - waxy coating excreted
by epidermis
• Mesophyll - middle of leaf
Palisade Layer - photosynthesis
– ___________
– Spongy layer - gas exchange
Modified Leaves
Tendrils
• ___________attachment
• Bracts –modified
leaves that
surround a group
of flowers
• Spines protection
• Storage Leaves
- succulents
Uptake of
Nutrients
Hydroponic
_______________
cultures used to
determine which
chemical elements are
essential.
17 essential elements
needed by all plants
NEED TO KNOW THE CHART!!!
Soil
• Develops from weathered
rocks
– Anchors plants
– Provides water
– Provides dissolved minerals
Soil Texture
• Pertains to sizes of soil
particles
– includes the following:
• sands (0.02 - 2 mm)
• silt (0.002 - 0.02 mm)
• clay (less than 0.002 mm)
• Loams (40/40/20)
Control Systems in
Plants
Plant Hormones
• Coordinates growth
• Coordinates development
• Coordinates responses to
environmental stimuli
Auxins
• Stimulates stem elongation
• Stimulates root growth
• Stimulates differentiation and
branching
• Stimulates development of
fruit
• Stimulates apical dominance
• Stimulates phototropism and
gravitropism
Auxin Control
• Auxin stimulates
growth
• Auxin block on
right causes cells
to elongate and
the plant bends
left
• Auxin block on left
causes cells to
elongate the the
plant bends right
•
•
•
•
Acid Growth
___________
Hypothesis
Proton pump stimulated by auxin lower pH of wall
H+ activates Enzyme
Enzyme breaks hydrogen bonds in cellulose
Wall takes up water and elongates
Auxin Others
• Promotes secondary
growth by stimulating
vascular cambium and
secondary xylem
• Promotes adventitious
root at the base of a cut
stem
• Promotes fruit growth
without pollination
(seedless tomatoes)
Cytokinins
• Works with Auxin:
– more cytokinin - shoot buds
develop
– more auxin - roots develop
• Stimulates germination
• Delays Senescence
Gibberellins
• Promotes seed and bud
germination
• Promotes stem elongation
• Promotes leaf growth
• Stimulates flowering and
fruits
– (with auxin)
Ethylene
• Promotes fruit ripening
• Controls Abscission (causes
leaf loss)
Phytochromes
• Function as photoreceptors / red (660nm) to
far red (730nm)
• Activates kinases (regulatory proteins)
Red vs. Far Red Response
Why plants are
important?
• Food!
• Humans have domesticated plants for
13,000 years.
• ____ of all the calories consumed by
humans come from six crops: Wheat,
Rice, Maize, Potatoes, Cassava, and
Sweet Potatoes.
• Also, we use plants to feed cattle, 5-7kg
to produce 1 kg of beef.
Pyramid of Net
Productivity
Plants remove CO2
25% of all US
•_____
Prescription Drugs
contain one or more
active ingredients from
plants.
50% earth’s species
•____
will become extinct
within the next 100
years (larger than the
Permian or Cretaceous)
•Only 5,000 of 290,000
species have been
studied.
•3-4 species per hour,
27,000 per year!
Cinchona tree
• Bark contains
__________
• Grows in the
Andes in peru
• Used since the
early 1600’s to
treat malaria
Aspirin
• Acetylsalicylic acid or ASA
• Dates back to 3000 B.C.
• Greek Physician Hippocrates
prescribed it.
trees
• From Willow
_____________
and
other Salicylate-rich plants
(leaves and bark)
• Scientists at Bayer began
investigating acetylsalicylic
acid as a less-irritating
replacement for standard
common salicylate medicines.
By 1899, Bayer named it this
Aspirin
Ecology
Hadley Cell
Hadley Cells
Biomes
Charles Darwin
• Differential
Reproductive
Success Adaptation
• 1859 Origin of
Species.
• Romanes –
Neodarwinism
& The Modern
Synthesis
(Genetics)
Evolution in the Lab
Allopatric Speciation
Sympatric Speciation
Hugo De Vries
• Evening Primrose
Need to know to
here now!