1

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

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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

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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)

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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

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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)

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(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

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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

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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

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• 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

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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