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What is a Plant?General characteristics:
MulticellularEukaryotic
Autotrophic (photosynthetic)
Sessile(stationary, does not move)
What do plants need to grow?
Space Temperature Sunlight Water
CO2Nutrients
(Nitrogen)Time
What do plants need to grow?
PHOTOSYNTHESIS!
• CO2 + H2O + Sunlight C6H12O6 + O2
Sunlight Water
Structure/Organs
of plants• Stem
• Root
• Leaf
• Seeds/flower/fruit
Match:
Cell Wall
Chloroplast
Mitochondria
Nucleus
Ribosomes
Vacuole 6
Monocot
Plants
Fibrous roots
2
Monocotyledons
Parallel veins
one seed-leaf
Characteristics of Monocotyledons
leaves have parallel veins
Herbaceous (stems are not woody)
plantse.g. grass, maize
Dicot Plants
Taproot
Di-cotyledons
Veins in network
. two seed-leaves
Characteristics of
Dicotyledons
. leaves have veins in network
. e.g. trees, sunflower, rose ROOTS
Materials: Carrot, Water roots,
Weeds
3
Why does a plant need
roots?
1. To anchor a plant in
the ground
2. To absorb water and
nutrients
from the soil like a sponge
3. To store them for later on
as Glucose9
Types of roots
Help prevent top soil
from being washed away
by heavy rain.
Taproot
8
Fibrous Root
These roots go deep
underground
and store high quantities of
starches or sugars.
STEMS
Materials: asparagus, celery, food
coloring, lily stem
Why does a plant need
a stem?To produce
To hold the leaves up to
sunlight
To transport nutrients from
roots to leaves
leaves, branches andflowers
16
How does water move against gravity?
Capillary action
Transpiration (by the leaves)
C
O
H
E
S
I
O
N
A
D
H
E
S
I
O
N
How does water move against gravity?
Capillary action -– ability
for water to flow in
narrow spaces in the
opposite direction of
gravity
4
How does water move against
gravity?
*Adhesion – the property
of water sticking to other
things
*Cohesion – the property
of water molecules
sticking to other water
molecules
C
O
H
E
S
I
O
N
A
D
H
E
S
I
O
N
How does water move against
gravity?
*Transpiration – water loss
(Evaporation) through the
leaves
*Turgor pressure- the
water pressure exerted by
water inside the cell against
the cell wall.
Transpiration (by the leaves)
Vascular tissue
phloem
carries sugars
(food) from the
leaf to the roots
Phloem food
xylem
carries H2O and
minerals from the
roots to the leaf
xylem water
Tissues made of tube-like cells that move food and
water through the plant (like veins and arteries)
P X
LEAVES
Materials: Collected leaves
Why does a plant need
leaves?For Photosynthesis For Transpiration
For Gas Exchange
CO2 O2 Water loss
Through the stomata and
guard cells
To “Breathe”
Using the stomata and guard cells
Sugar
To Make Food
17
The Structure of a Leaf
StomataAllows gas exchange
Guard CellsOpen/close the stomata
1. Cuticle: waxy layer that protects leaf against water loss
2. Vascular Tissue (“veins):
Xylem- transports water
Phloem- transports food
3. Mesophyll: contains cells that perform photosynthesis chloroplasts
4. Stomata and Guard cells:
opens and closes to allow gas exchange
Water loss: results because of transpiration when the stomata is opened
5
Structure of a Leaf
Stoma- singular
Stomata-plural
Cuticle
2 Guard Cells(surround each stoma)
Xylem &
Phloem
Stoma(Opening)
Leaf Cross-Section
StomataHow do the guard
cells react to the
availability of
water?
Dry – guard cells
CLOSE
lots of H2O –
guard cells OPEN
http://www.ualr.edu/~botany/images.html
Function of Guard Cells
SEEDS
Materials: various seeds
Structure & Function of Seeds
Seeds are plant embryo’s that holds, protects, and provides nutrients for the embryo that will eventually become a new plant.
Cotyledon- part of the seed that gives rise to the first embryonic leaves of a seedling.
6
Gymnosperm –
cone-bearing
plants
Angiosperm-
flowering plantsThe Development of Plants
Mosses and
their relatives
Ferns and
their relatives
Cone-bearing
plants
Flowering
plants
Blue green
algae
Water-Conducting
Vascular Tissue
Seeds
Flowers
Seeds Enclosed in Fruit
Over time, plants
have gone from
simple to complex.
Gymnosperms
Angiosperms
Eukaryote cell
1. Using the
cladogram, what
characteristics do
ferns have?
FLOWERS
Materials: alstroemeria lilies for
dissection, scissors
Why does a plant need
flowers?
Attract pollinators
(colors, smell,
nectar)
Site for Sexual
Reproduction
Become fruits
(carry seeds)
PollinationPollination is the
transfer of pollen
(male gamete) to
the surface of the
stigma (female
part)
7
Self-PollinationSelf pollination
may occur if the
pollen arrives at
the stigma of the
same flower or
another flower on
the same plant
Cross-PollinationCross pollination
occurs when the
pollen arrives at the
stigma of a flower
of another plant of
the same species
Methods for Flower Pollination
1. Animals
– Brightly colored
– Tasty (nectar!)
– Fragrant
(pheromones?)
– Often large
2. Wind-dispersed
– Not brightly colored
– Not tasty
– Not fragrant
– Often small
- Pistil: female
- Style-sticky to trap pollen
- Stigma
- Ovule- becomes the fruit
- Stamen: Male
- Anther (pollen)
- Filament
- - attract pollinators
- Sepal- protect flower bud
Structure of a Flower
Flower Dissection Directions
1. Obtain one flower per group from the teacher.
Observe the flower and its main organs.
2. Make a sketch of the flower.
3. Be sure to label the following parts: petals,
sepals, carpel, stigma, style, ovary,
stamen, anther, filament.
8
Plant
Reproduction
and
Classification
PollinationInsects, wind, birds or other agents
are often required for the transfer
9
Human ViewJust another yellow flower
Bee’s viewUV light reveals attractive patterns!
Fertilization
After pollination, a pollen tube forms, producing a path that the sperm will follow to the egg (in the ovary)
10
(then, a seed develops)
From Flower to Fruit
• All fertilized
“flowers” turn
into “fruit” after
fertilization
• Not all “fruit” are
what we call
“fruit”…..
Fruit Development
Fruit Development Next problem….getting the seeds dispersed!
Flowering plants have different
adaptations to enable their
seeds to be dispersed as far
away as possible.
The different methods of seed
dispersal are…
by wind
by animals
by water
by splitting open forcefully
11
Fruits/seeds
Fruits/seeds
by splitting open
Fruits/seedsFruits/seeds
At a glance…
by wind
seed dispersal
by water
Adaptations for reproduction
plants
Fruits/seeds
by animals
Reproduction in plants — getting the seeds dispersed
What are the adaptations that help these
fruits/seeds to be dispersed?
maple
shorea
Dispersal by wind
small
light
dry
wing-like
dandelion
Reproduction in plants — getting the seeds dispersed
tomato
Dispersal by animals (eaten)
bright colours
sweet
juicy
What are the adaptations that help these
fruits/seeds to be dispersed?
Dispersal by animals
(carried)
small
hooks stiff hairs
Reproduction in plants ― getting the seeds dispersed
coconut
saga
Dispersal by water
buoyant
waterproof
air spaces
What are the adaptations that help these
fruits/seeds to be dispersed?
Dispersal by splitting open
dry and hard fruit wall
Fruits/seeds
• dry and hard fruit wall
Fruits/seeds
brightly coloured
sweet
juicy
by splitting open
Fruits/seeds
small
light
dry
wing-like
Fruits/seeds
buoyant
waterproof
air spaces
At a glance…
by wind
seed dispersal
by water
Adaptations for reproduction
plants
Fruits/seeds
small
hooks
stiff hairs
by animals
Plant Classification
Non-flowering
Plants
Flowering
Spore-
bearingCone
bearing
No roots
Non-Vascular
Vascular
with
Roots
1 seed-
leaf
2 seed-
leaves
12
Plant Kingdom
Flowering
Plants
Non-flowering
Plants
A plant can be divided into 3 parts
. 3 groups
Ferns
(Vascular)
Mosses
(Non-Vascular)
Gymnosperms
(Vascular)
Non - flowering Plants
Do NOT produce flowers
Examples of
Mosses
spore
s
Spore-producing capsuleCharacteristics of Mosses
• Nonvascular plants grow close to the ground to absorb water and nutrients.
• Simplest plants
• No true roots
• no vascular system
13
• roots, feathery leaves & underground stems
Characteristics of Ferns
• have vascular tissues (allows ferns to
grow higher off the ground when
compared to mosses)
• Adapted to Damp &
shady places
• Spore-producing organ on
the underside of leaves
(for reproduction)
needle-shaped leaves
• roots, woody stems
Characteristics of Gymnosperms
• needle-shaped leaves
• tall evergreen trees
• cones have reproductive
structures
• Well adapted to dry
places
• vascular tissues
14
2 groups
Monocots Dicots
Flowering
Plants
roots, stems, leaves
vascular tissues (transport)
flowers, fruits (contain seeds)
Plant Classification
Non-flowering
Plants
Flowering
Spore-
bearingNaked
seeds
No roots
Non-Vascular
Roots
Mosses
Ferns
Gymnosperms
1
seed-
leaf
2
seed-
leavesMonocots Dicots
Angiosperms