Transcript Honors - Fulton County Schools

Living organisms are classified into
3 Domains
1. Bacteria
2. Archaea
3. Eukarya
4 Kingdoms in this
Domain
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Domain Eukarya has 4 Kingdoms
1. Kingdom Protista
2. Kingdom Fungi
3. Kingdom
Plantae
4. Kingdom Animalia
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Characteristics of Plants
 Eukaryotes
 Multicellular
 Can
not move
 Autotrophic-can Photosynthesize
 Thick cell walls made of
cellulose
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Adaptations of Plants
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Cuticle to prevent water loss
Leaves for carrying out photosynthesis
Roots to anchor and absorb water and minerals
Stems for support and transport of food, water
and minerals
Vascular tissues for transport in some plants
Most have seeds for reproduction
Alternation of generations
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Plant Evolution
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Plants are divided into vascular and
nonvascular
The Vascular plants are divided into
seed plants and non seed plants
The Seed Plants are divided into
those with cones and those with
flowers
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Vascular/Nonvascular
Seed/Seedless
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Bryophytes are the non vascular plants
with focus on the moss
The Pterophytes are the ferns and they
are vascular and seedless
The Seed plants consist of the
Gymnosperms with cones and the
Angiosperms with flowers.
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Ginkgophyta
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A division of seed plants that
have only one living species
The leaves of the plant are fan shaped
For centuries it was thought to be extinct
in the wild, but is now known to grow wild
in eastern China. The wild status of
ginkgos there is uncertain.
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Evolution of Plants
4 major
evolutionary
steps
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Alternation of Generations
Gametophyte and Sporophyte
Notice that the
more advanced
plants have a
dominant
Sporophyte
and the less
advanced
plants have a
more dominant
Gametophyte
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Moss Life Cycle
http://intro.bio.umb.edu/111-112/112s99Lect/life-cycles.html
http://www.sumanasinc.com/webcontent/anisamples/majorsbiology/moss.html
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Fern Life Cycle
http://intro.bio.umb.edu/111-112/112s99Lect/life-cycles.html
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Alternation of Generations
By definition,
all plants
alternate
generations
Gametophyte
n=haploid
Sporophyte
2n=diploid
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Vascular Tissue
Xylem
specialized cells for carrying water and
dissolved minerals from the roots
The specialized cells found in Xylem
are the tracheids
Phloem
cells for carrying food produced in the
leaves through photosynthesis to all
parts of the plant
Vascular Cambium
The specialized tissue that gives rise to new
Xylem and Phloem
This is the tissue that brings about the
growth of a tree trunk
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Leaf Structure
http://www.purchon.com/biology/flash/leaf.swf
•The primary
function of leaves is
photosynthesis
•Most photosynthesis
takes place in the
Palisade mesophyll
•Spongy mesophyll
is loosely packed cells
and permits gases to
move between
palisade cells and the
outside of the leaf
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Root Structure
•Apical
Mesistems are
found at the tips
of roots
•This is an area
of active growth
•There are also
meristems found
at the tips of
growing stems
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Root Functions
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Anchor plants
Absorb water and minerals
May store carbohydrates (carrots, potatoes,
turnips)
May store water for dry periods
Plant Cells use minerals, such as nitrogen and
potassium in LARGE amounts; called
macronutrients
Minerals needed in SMALL amounts are called
micronutrients
Mineral deficiencies or excess minerals can kill
plants
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Transport in Plants
•Transport in a plant involves
movement of water, minerals, macro
and micronutrients by vascular
cambium
•Xylem transports water and
minerals from the roots
•Phloem transports food from the
leaves to all parts of the plant
•Root Hairs aid in the absorption of
water and minerals because it
increases the surface area of roots
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Structure and Function of Stomata
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If water enters the guard cells, they swell up
and the stomata opens
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If water leaves the guard cells, they become
flaccid and the stomata closes
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Angiosperm or Flowering Plant
Reproduction
The
Sporophyte
is the
dominant
stage in the
life cycle of
the
Angiosperms
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Basic Flower Structure of an
Angiosperm
http://plantandsoil.unl.edu/croptechnology2005/plant_phys/?what=animationList&informationModuleId=1087230040
•Sepals protect the
flower bud from insect
damage and dryness
•The color, scent, and
nectar of flowers attracts
insects, bats, and birds
•These animals help to
transfer the pollen from
the anthers of one flower
to the stigma of other
flowers-called pollination
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Complete and Incomplete Flowers
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Perfect Flowers: have both
male and female
reproductive structures.
Imperfect Flowers: have
either male or female
structures
Complete flowers: have four
basic structures: petals,
sepals, a stamen and a
pistil
Incomplete flowers: have
one or more of these
structures lacking
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Pollen Tube Growth and
Fertilization in Angiosperms
•The Pollen grains are
transferred to the
Stigma where the
pollen grain produces a
Pollen tube
•The pollen tube grows
down the style into the
ovary where it fuses
its nuclei with the
nuclei of the ovule
•The fertilized ovule
becomes a seed and
the ovary develops
into the fruit of the
plant
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Plant Responses
Example: Sensitivity to pressure or touch
This can be protective for the plant
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Phototropism
Positive
Phototropism:
the plant is
bending
toward the
sunlight
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Phototropism
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Phototropism is illustrated by the
movement of plants in relation to light
source direction
Light causes the hormone auxin to move
to the shaded side
The auxin causes the cells on the shaded
side to elongate
As a result, the shoot bends toward the
light and exhibits positive phototropism25
Thigmotropism
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Thigmotropism is a plant growth response to
touching a solid object
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Tendrils and stems of vines, such as morning
glories, coil when they touch an object
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Thigmotropism allows some vines to climb other
plants or objects, thus increasing its chance of
intercepting light for photosynthesis.
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Geotropism or Gravitropism
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Gravitropism
 Gravitropism
is a plant growth
response to gravity
 A root usually grows downward
and a stem usually grows upward
 Roots are positively
gravitropic and stems are
negatively gravitropic
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Plant Hormones
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Auxin-This hormone promotes cell
elongation
Auxin is found in the apical meristems of
plants
Gibberellins help the plants to grow
taller
Gibberellins also increase the rate of
seed germination and bud development
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Angiosperms are Divided into
Monocots and Dicots
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Monocots and Dicots Again
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Monocot and Dicot Seed Structure
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Monocot and Dicot Leaf Veins
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Monocot and Dicot Flower Pedals
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Monocot-pedals in groups of three or
multiples
Dicots-pedals in groups of 4s or 5s
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Monocot and Dicot Stem
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Monocots-vascular
tissue scattered
Dicots-vascular
tissue around edge of
stem
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Examples of Monocots and Dicots
 Monocots
include: grasses, oats,
wheat, orchids, lilies and
palms
 Dicots include: shrubs, trees
(except conifers) wild flowers
and some garden flowers
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Monocot and Dicot Seed Anatomy
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Food is stored in the
cotyledon for the
embryo
The seed coat
functions as a
physical barrier
Epicotyls becomes
the leaves of plant
Hypocotyls
becomes the stem
Radicle becomes
the root
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Seed Germination
Requirements for
seed germination
include:
•Enough water to
activate the
metabolism of embryo
•Sufficient oxygen
for respiration
•Suitable
temperature for
growth of that species
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Seed Dispersal
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Seeds dispersal is
completed by birds,
small animals, wind,
and water
The tough, fibrous
outer covering of a
coconut provides
protection as well as
a floatation device
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Seed Germination
Seeds are stored food with an
Embryo
Some species need unusual conditions
for Germination:
Pass through acidic environment of
an animals digestive system
 Some require freezing temperatures,
extensive soaking in water (rice),
exposure to fire (conifers/pines), or
certain day lengths
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Genetic Engineering of Plants
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Plants can be genetically engineered to:
 Be
more tolerant of different
climates & soils
 Produce more fruit
 Be more nutritious
 Be more resistant to insects and
herbicides
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