Introduction to PlantsIntroduction to Plants

Essential Questions:Essential Questions:Why are plants important to life on Earth?Why are plants important to life on Earth?

How have they adapted to life on land?How have they adapted to life on land?How have plans evolved to respond to their How have plans evolved to respond to their

environment?environment?

What do Plants Need to Survive?What do Plants Need to Survive?

Label your picture in NotesLabel your picture in Notes:: SunlightSunlight to make Glucose to make Glucose WaterWater (and Minerals) (and Minerals) Carbon Dioxide Carbon Dioxide to make to make

Glucose!Glucose!Why do we need Plants?Why do we need Plants?

Source of Source of SugarSugar (energy) for the (energy) for the base of the energy pyramid!base of the energy pyramid!

Major source of Major source of OxygenOxygen!!

Where did Plants come from?Where did Plants come from? Plants likely evolved Plants likely evolved

from plant-like from plant-like ProtistProtist green algaegreen algae from a watery from a watery environment. environment. OparinOparin: Life came : Life came

from the oceans.from the oceans. Likely evolved Likely evolved

around 500-400 around 500-400 million years ago!million years ago!

Plant General Plant General CharacteristicsCharacteristics

1.1. Carry out photosynthesis (autotrophs)Carry out photosynthesis (autotrophs)2.2. Produce cellulose in their cell wallsProduce cellulose in their cell walls3.3. Non-motile (don’t move around)Non-motile (don’t move around)4.4. Reproduce sexually and asexuallyReproduce sexually and asexually5.5. Have specialized tissues and organsHave specialized tissues and organs

Plant DiversityPlant Diversity

Bryophytesnon-vascularland plants

Pteridophytesseedless

vascular plants

Gymnospermpollen &

“naked” seeds

Angiospermflowers & fruit

seed plants

vascular plants

mosses fernsconifers flowering plants

colonization of land

Bryophytes – Non Vascular PlantsBryophytes – Non Vascular Plants

IncludesIncludes: mosses, liverworts, hornworts: mosses, liverworts, hornworts First land plants; had to overcome obstaclesFirst land plants; had to overcome obstacles

avoid drying out (desiccation) – live in moist areasavoid drying out (desiccation) – live in moist areas develop a means of support (roots and stems)develop a means of support (roots and stems) develop new reproductive methodsdevelop new reproductive methods obtaining nutritionobtaining nutrition No vascular tissue, so they are close to the ground to No vascular tissue, so they are close to the ground to

draw up water by draw up water by osmosisosmosis! Their reproduction also ! Their reproduction also relies on the use of water!relies on the use of water!

Bryophytes: mosses & liverwortsBryophytes: mosses & liverworts

Tracheophytes – vascular plantsTracheophytes – vascular plants Pteridophyta - fernsPteridophyta - ferns

Have Have vascular system vascular system (can grow taller than (can grow taller than mosses and do not have to directly live in water)mosses and do not have to directly live in water)

SeedlessSeedless – produce by – produce by sporesspores (still rely on water and wind for reproduction)(still rely on water and wind for reproduction)

Pteridophytes: FernsPteridophytes: FernsSelaginella Psilotum

Horsetails Ferns

Tracheophytes – Vascular plantsTracheophytes – Vascular plants GymnospermsGymnosperms – means “ – means “naked seednaked seed”, not ”, not

protected by fruit. Can reproduce through protected by fruit. Can reproduce through wind or other methods on land via seeds!wind or other methods on land via seeds! Class Ginkoopsida Class Ginkoopsida – Gingkos; one species exists – Gingkos; one species exists

today, living fossiltoday, living fossil Class Cycadopsida Class Cycadopsida – Cycads; found in tropics– Cycads; found in tropics Class Pinopsida Class Pinopsida – cone bearers; 9 families contain – cone bearers; 9 families contain

over 300 species, evergreens: pines, spruce, over 300 species, evergreens: pines, spruce, hemlocks, firshemlocks, firs

What does Vascular Tissue mean? Means they have xylem (water) and phloem (sugar) to transport water up from the ground into the rest of the

plant! Can grow very tall unlike mosses and ferns!

Gymnosperm: conifers Gymnosperm: conifers

Earth's oldest living inhabitant "Methuselah" at 4,767 years, has lived more than a millennium longer than any other tree.

BRISTLECONEPINE TREE

Tracheophytes – vascular plantsTracheophytes – vascular plantsAngiospermsAngiosperms – flowering plants, produce a form of – flowering plants, produce a form of fruitfruit! (A wall ! (A wall

of tissue surrounding a seed.) “hidden seed.”of tissue surrounding a seed.) “hidden seed.” Gives animals a tasty treat to place their offspring elsewhere. Can Gives animals a tasty treat to place their offspring elsewhere. Can

reproduce on land.reproduce on land. Two classes of angiosperms are based upon the number of Two classes of angiosperms are based upon the number of CotyledonCotyledon: tiny seed leaves that store or absorb food for developing : tiny seed leaves that store or absorb food for developing embryo. embryo.

Class Monocotyledonae Class Monocotyledonae – Monocots (1)– Monocots (1) Class Dicotyledonae Class Dicotyledonae – Dicots (2)– Dicots (2) Have Unique life spans.Have Unique life spans.

Those who die in one season are called Those who die in one season are called annualsannuals.. Those who die in two years are called Those who die in two years are called biannualsbiannuals.. Those who live many years are called Those who live many years are called perennialsperennials..

Angiosperm: flowering plants Angiosperm: flowering plants

Types of Angiosperms:Types of Angiosperms:Monocots versus DicotsMonocots versus Dicots

Plant Structure: RootsPlant Structure: Roots RootsRoots anchoranchor plants into the plants into the

ground, ground, absorbabsorb water & minerals water & minerals from the soil, from the soil, protectprotect the plant from the plant from bad bacteria/fungi, and bad bacteria/fungi, and transporttransport these materials to the stem.these materials to the stem.

Contain Contain xylemxylem and and phloemphloem in the in the center of the root.center of the root.

Root pressureRoot pressure – dew is an example of root – dew is an example of root (pressure forcing excess water out of the (pressure forcing excess water out of the plant)plant)

The The root caproot cap burrows through the burrows through the soil and the cells are replenished by soil and the cells are replenished by the the apical meristemapical meristem..

MeristemMeristem = areas of rapidly = areas of rapidly dividing cellsdividing cells

Plant Structure: StemsPlant Structure: Stems StemsStems can be either can be either woodywoody or or

herbaceousherbaceous. . TranspirationTranspiration – as water – as water

evaporates, the energy released evaporates, the energy released pulls water up the stempulls water up the stem

Vascular tissues are arranged Vascular tissues are arranged differently in stems than leaves.differently in stems than leaves. Monocots: scattered in stemMonocots: scattered in stem Dicots: circular pattern in stemDicots: circular pattern in stem

XylemXylem – transports – transports waterwater & & mineralsminerals

PhloemPhloem – transports – transports sugarssugars & & hormoneshormones Portion of a plant that stores sugar Portion of a plant that stores sugar

is called a is called a sinksink..

Plant Structure: LeavesPlant Structure: Leaves Permit exchange of COPermit exchange of CO22, O, O22, and , and

HH22O with the environmentO with the environment Site of photosynthesis (SUN!)Site of photosynthesis (SUN!) LeavesLeaves are protected by a waxy are protected by a waxy

cuticlecuticle.. PetiolePetiole – vascular tissues extending – vascular tissues extending

from stem to leaf (appear as veins)from stem to leaf (appear as veins) MesophyllMesophyll – contain – contain chlorophyllchlorophyll Guard cells & StomataGuard cells & Stomata – regulate – regulate

water loss through the underside of water loss through the underside of the leaf (Transpiration)the leaf (Transpiration)

MonocotsMonocots: parallel veins: parallel veins DicotsDicots: net veined: net veined

Why are Roots, Stems & Leaves Why are Roots, Stems & Leaves important?important?

Root pressure Root pressure – dew is an example of root – dew is an example of root pressure (forcing excess water out of the plant)pressure (forcing excess water out of the plant)

TranspirationTranspiration – as water evaporates, the energy – as water evaporates, the energy released pulls water up the stemreleased pulls water up the stem

Capillary pressure Capillary pressure – water uses – water uses cohesioncohesion (unlike (unlike particles stick together) and particles stick together) and adhesionadhesion (like (like particles stick together) to push its way up xylem particles stick together) to push its way up xylem in plants; limiting factor in height of trees.in plants; limiting factor in height of trees.

Plant Responses: TropismsPlant Responses: Tropisms Plants respond to their environment as Plants respond to their environment as

other organisms do.other organisms do. PhotoperiodismPhotoperiodism affects the timing of flower affects the timing of flower

production.production. Duration of light and dark periods in the dayDuration of light and dark periods in the day Short-day plants, Long-day plants, day-neutral plants Short-day plants, Long-day plants, day-neutral plants

TropismTropism – a plant’s response to an external – a plant’s response to an external stimulus that comes from a particular stimulus that comes from a particular direction.direction.

Involve Involve growthgrowth, so they are , so they are notnot reversiblereversible.. PhototropismPhototropism (Light) (Light) GravitropismGravitropism (Gravity) (Gravity) ThigmotropismThigmotropism (Touch) (Touch)

Nastic movementNastic movement –Do –Do notnot involve involve growth, so are growth, so are reversiblereversible.. ExampleExample: folding of a venus flytrap.: folding of a venus flytrap.

Plant Responses: HormonesPlant Responses: Hormones HormonesHormones cause a cause a

physiological change either in physiological change either in growthgrowth or or developmentdevelopment.. AuxinsAuxins (IAA) – stem elongation. (IAA) – stem elongation. GibberellinsGibberellins – increase rate of – increase rate of

seed germination and allows the seed germination and allows the stem to grow taller.stem to grow taller.

CytokininsCytokinins – stimulate proteins for – stimulate proteins for cell division and extends the life cell division and extends the life of the plant.of the plant.

EthyleneEthylene – ripens fruits and the – ripens fruits and the emergence of seeds from the soil.emergence of seeds from the soil.

Abscisic Acid Abscisic Acid – helps leaves – helps leaves prevent water loss by hardening prevent water loss by hardening certain leaf cells.certain leaf cells.

Final Note: Specialized TissuesFinal Note: Specialized Tissues Meristematic tissue Meristematic tissue – only tissue that produces new – only tissue that produces new

cells by mitosis, found on edgescells by mitosis, found on edges ParenchymaParenchyma – used for storage, surrounded by – used for storage, surrounded by

vascular tissuevascular tissue Vascular tissue Vascular tissue – like arteries and veins!– like arteries and veins!

XylemXylem – transports materials up from the roots to leaves – transports materials up from the roots to leaves and supports the plants as “wood” after the cell diesand supports the plants as “wood” after the cell dies

PhloemPhloem – transports materials down from the leaves to – transports materials down from the leaves to roots and stemroots and stem

Vascular Cambium Vascular Cambium – makes more vascular tissue– makes more vascular tissue Cork Cambium Cork Cambium – outer bark of trees– outer bark of trees