What is a plant???

• Organism that is:• Multicellular• Eukaryote• Autotrophic• Has Cell wall

• Photosynthesizes

Plants evolved from Green Algae

Brainstorm with a neighbor: What are differences between algae

and plants?

Challenges from life in water to life on land

1. Obtain resources from BOTH air and soil

• Roots: below ground and absorb nutrients and water

• Shoots: above ground and convert sunlight and CO2 to energy

• Vascular system: moves water and nutrients between roots and shoots.

SHOOTS

ROOTS

Challenges from life in water to life on land

2. Remaining upright and not falling over

• Lignin: chemical that hardens the cell wall to give strength and support to plants.

Challenges from life in water to life on land

3. Maintaining Moisture

• Cuticle: Lipid, waxy covering that prevents water evaporation

• Stomata: Pores on underside of leaf that regulates water and gas exchange

– Guard cells: open and close the stomata

Hole = stomata

Cells around hole = guard cells

Challenges from life in water to life on land

4. Reproduction on land

• Need ways to prevent seeds from drying and ways to disperse

BRYOPHYTES

• Moss

• Lack lignin and are considered non vascular plants

• Require water to reproduce because gametes have flagella

Pteridophytes

• First group of plants to have vascular tissue (lignin)– Able to grow taller now

• Ferns, horse tails

• Reproduce through spores on underside of leaf and no longer dependent on water

Gymnosperms

• First seed bearing plants– Naked seeds because they are not surrounded by

fruit.

• Conifers and needle leaf trees

• Pollen cone– Male reproductive structure

• Pollen grains– Male gamete, adapted to dry environment and

transport through wind.

• Pine cone– Female reproductive structure

• Seeds– Plant embryo packaged with food supply inside a

protective coat.

ANGIOSPERM

• Flowering plants• Fruit: Ripened ovary used to protect seeds

and disperse them.

Parts of a Flower

• Petals– Brightly colored to

attract pollinators

• Stamen– Male reproductive

structure– Anther: holds pollen

• Male gamete

– Filament: holds up anther.

Parts of a Flower• Carpel– Female reproductive

structure

– stigma: sticky to catch pollen

– Style: long tube that connects stigma and ovary

– Ovary: holds ovules (eggs)

How do Plants Reproduce?

• Pollination– Rely on animals to

transport pollen from male to female reproductive structure.

– Brightly colored petals attract pollinators

• Double Fertilization:–When pollen travels

down style it splits into 2 sperm cells• 1 fertilizes the

ovule to create seed• Other creates

food supply

Seed Dispersion

• Once pollination has occurred seeds need to spread to allow for new plant growth– Burrs can stick to animals and move – Fruit can be eaten and then the core thrown– Some seeds need to be completely digested in

order to grow.– Water currents and wind.

• Annuals:– Go through a complete

life cycle in one year.

Merigolds

Baby blue eyes basil

tomato

biennials

• Takes two years to complete the life cycle.

English daisy

Perennials

• Take several years to complete their life cycle.

agave

Baby’s breathCat tails

Roots

• Found underground– Anchor plant– Hold soil in place– Absorb water and

nutrients.

Types of Roots

• Fibrous Roots– SEVERAL THIN

BRANCHING ROOTS

Types of Roots

• Fibrous • Tap roots– Long root to anchor

plant– Several small horizontal

root hairs.

SHOOTS

• STEM– LOCATION OF LIGNIN– XYLEM AND PHLOEM

TO MOVE WATER AND NUTRIENTS THROUGH PLANT.

• Leaf– Location of

photosynthesis – 2 parts• Petiole• Blade

Types of Tissue in Plants

• Dermal Tissue–Acts as a

protective barrier for the plant.–Secretes the

cuticle.–Outer most layer

of tissue.

Vascular Tissue• Contains lignin to give support.

• XYLEM: transport water and nutrients from roots to shoots–Transpiration is

the evaporation of water through leaves that drives the process

Vascular Tissue• .

• PHLOEM: transports sugars due to diffusion (high concentration to low concentration).

Ground tissue

• Tissue found between dermal and vascular tissue.

• Most abundant tissue type

• Location of photosynthesis

Primary growth• Growth upwards and downwards in height.• Occurs at root caps and buds in plants.

Secondary growth• Growth in width outwards.• Adds new xylem and phloem.• Every 2 rings = 1 year of growth for tree rings.