Highlights of Plant Evolution Chart:

I. Bryophytes - mosses = many plants growing in a tight pack.• No waxy cuticle and do not retain developing embryos w/i mother plant’s

gametangium. • Need water to reproduce; sperm are flagellated, must swim through water to

reach eggs• No vascular tissue to carry water(grow low to ground) and lack lignin• Like damp, shady places• Green spongy plant = gametophyte (male & female are separate plant shoots)

(n)• Taller brown shoot with a capsule, grows out of gametohyte = sporophyte (2n)

Alternation of Generations -

2 generations that take turns producing each other

• Gametophytes produce eggs and sperm; must unite to form a zygote, which forms new sporophytes.

• Sporophytes produce spores

• Spores can develop into a new organism without uniting, & have a tough coat to resist harsh environments.

• The new organism then produces gametophytes again.

• Gametophyte = larger more obvious plant in mosses

• Moss- Gametophyte (left) and Archegonium (female gametophyte) (right)

(Antheridium = male gametopyte.)

• Sporophyte generation (left) and Sporangia (right)

• Moss is cool! E.C. for bringing in moss with both generations. (In late spring.)

• II. Ferns - diverse with 12,000 species, most in tropics, many in temperate woodlands of U.S.

• Evolution of vascular tissue (xylem and phloem)

• Sperm are still flagellated-must swim through a film of water to fertilize eggs

• Are still seedless - have spores

• During Carboniferous Period, ferns in swamp forests converted to coal - (black sedimentary rock made up of fossilized plant material)

• Alternation of

Generations in ferns.

• Sporophytes are diploid and gametophytes are haploid

• Sporophyte is the dominant stage in ferns. (Gametophyte was dominant in mosses)

• Heart shaped gametophyte = prothallus

• III. Angiosperms - flowering

plants, dominate most regions

• 250,000 species vs. 700 conifer species

• Supply nearly all our food and fiber for textiles, some lumber

• Refined vascular tissue - water transport more efficient

• Evolution of flower = responsible for unparalleled success

• Flowers - display male and female parts

• Insects and animals transfer pollen from male part of one flower, to female part of another flower. Advantage? (vs. wind)________

• Flower = short stem w. modified leaves: sepals, petals, stamens, carpels.

Label flower to left w. all

flower terms below:

Sepals - green, enclose flower before it opens

Petals - attract insects & other pollinators

Stamen - filament (stalk) bearing a sac called anther. Anther is male organ in which pollen grains develop.

Carpel = sticky tip called stigma, which traps pollen, the style (stalk) and the ovary, a chamber containing one or more ovules. Egg develops here.

Angiosperm life cycle is above:

• Sporophyte is the familiar plant; female gametophyte is w/I the ovule, & male gametophyte is the pollen.

• Pollen lands on stigma, tube goes down to ovule, deposits 2 sperm nuclei w/I female gametophyte = Double fertilization.

• One sperm cell fertilizes egg making zygote, developing into embryo.

• Second sperm cell fertilizes another female gametophyte cell which develops into a nutrient-storing tissue called endosperm.

Angiosperms cont:

• Embryo then has food w/I ovule

• Ovule develops into a seed

• Seed is enclosed W/I ovary = not naked.

• Fruit = ripened ovary of flower

• Fruit protects and helps disperse seeds

• Animals help disperse seeds too!

• All fruit and vegetable crops are angiosperms

• We will re-visit flowers and fruits in Ch.28 & in labs.

• Issues:Tropical rain forests are being destroyed for agricultural Coniferous forests are being destroyed for lumber and paper. Can you help???

End of Ch. 16

Chapter 28: Flowering Plants

Most of your notes for this Chapter will be found in your Flowering Plant Lab. However, here are some notes in addition

to your lab. • Angiosperms have dominated earth for 60 million years; 250,000 million species are known today.

• Monocots include orchids, palms, lilies, grains, grasses.

• Dicots include shrubs, trees (except for conifers), ornamental plants, many food crops.

• Know traits of each! (Lab) & See left.

• 3 Plant organs: roots, stems, leaves (Lee also lab)

1. Roots: Root hairs-increase surface area of root for absorption

Large taproots - store food such as starch for plant (Ex: carrots, turnips, sugar beets, sweet potatoes.)

2. Stems - Terminal bud is at apex of stem

when plant stem is growing in length. Axillary buds, in angle formed by a leaf and stem) are dormant.

Terminal bud produces hormones inhibiting growth of axillary buds = apical dominance, so plant can grow up to sun.

Axillary buds begin growing and develop into branches under certain conditions.

What is “pinching back?”

3 kinds of Modified stems:

Runner in a strawberry plant = horizontal stem - new plants emerge from tip of runner = asexual reproduction

Rhizome of an iris plant =horizontal underground stems = store food, & can bud new plants

Tubers are rhizomes ending in enlarged structures (potatoes). Eyes of potato are axillary buds, can grow when planted.

3. Leaves - flat blades (for light collection) and petioles (joins leaf to stem.) Celery is a big petiole.

Tendrils = modified leaves for climbing and support .

Spines of a cactus = modified leaf parts protecting plant. Cactus stem is photosynthetic.

• Plant Cells - have chlorophyll, large central vacuole, some have a multipart cell wall:

• Primary cell wall - laid down first

• Secondary cell wall - deposited between plasma membrane and primary wall, more rigid for support

• Parenchyma cells - most abundant cell, for food storage, photosynthesis. Only primary cell walls.

• Collenchyma cells - provide support in growing parts of plant. Only primary cell walls.

• Sclerenchyma cells - have thick secondary walls with lignin (wood). When mature, most are dead - rigid cells support plants. Make rope and clothing.

• 2 Plant Vascular Tissues:

1. Xylem - contains water conducting cells - move water & minerals up stem

2. Phloem -contains food conducting cells -transport sugars from leaves or storage tissue to other parts of plant

• 3 Tissue Systems continuous throughout plant:

1. Dermal-covers, protects, waxy coating

(epidermis)

2. Vascular- xylem and phloem; support, transport

3. Ground - bulk of young plant, fills spaces between epidermis and vascular. Photosynthesis, storage, support.

Types of ground tissue:

Cortex - in root,cells store food, take up water & minerals.

Endodermis - selective barrier in cortex-determines which substances pass between cortex and vascular tissue.

Pith - fills center of stem in dicots, food storage. (Con’t.)

Ground Tissue continued:Stomata - in epidermis of leaf and some stems, are tiny pores between guard cells - minimizes water loss, allow gas exchange.

Mesophyll - ground tissue of a leaf, for gas exchange and photoshythesis

???Can you name all parts of this leaf below ??? Label them!

Upper epidermis, Lower epidermis, Mesophyll, Cuticle, Vein, Xylem, Phloem, Guard cells, Stomata, Palisade Layer, Spongy layer

• What kind of plant organ is this, monocot or

dicot, and why? ______________________________________________________________________________________

• Review the structure of a flower, left.

• Go over life cycle of an angiosperm, below.

• This diagram shows how the male gametophyte (pollen) and female gametophyte (embryo within ovule) develop.

• The ovary may contain several ovules; only 1 is shown here.

• Please go over Steps 1-3 for the male and for the female on the diagram above. Males have ____surviving cells; females have ___.

• Above diagram shows pollination and double fertilization steps:

1. Pollination

2. Pollen form 2 sperm

3. Sperm travel through a pollen tube to ovule

4. Double fertilization occurs: – one sperm fertilizes egg forming diploid zygote which becomes the embryo;

– other sperm joins to form the triploid central cell, which develops into endosperm, nourishing the embryo

• Seed Formation:

Embryo develops cotyledons.

These organs absorb nutrients from endosperm.

Embryo develops into mature seed with tough protective seed coat enclosing endosperm.

Seed becomes dormant until seed germinates.

Dormancy allows time for seed dispersal, favors survival for good environmental contitions

• Fruit formation:

Fruit = mature ovary

Houses and protects seeds, disperses them from parent

Seed Germination:

• Seed takes up water and expands, ruptures its seed coat

• Embryo resumes growth (from dormancy)

• Embryotic root emerges, then shoot; a hook forms near its tip (protection)

• True leaves expand from shoot tip, and photosynthesize

• In pea, cotyledons remain behind in soil and decompose (see above)

• In beans, cotyledons emerge from soil and become seed leaves, which photosynthesize

• Only small fraction of seedlings live to reproduce

Plant Growth:

• Plants have indeterminate growth - continue to grow as long as they live - increases exposure to sunlight

• Have a finite life span: 3 examples:

∆ Annuals - mature, reproduce and die in 1 year or growing season. Ex: wheat, corn, rice, impatients

∆ Biennials - live for 2 years; flower and seed occur during second year. Ex: carrots

∆ Perennials - live and reproduce for many years. Ex: trees, shrubs, some grasses.

• Primary Growth = lengthening

Meristem - cells that divide and generate new cells and tissues (See lab and left diagram)

Secondary Growth = thickening

• Wood - dead xylem tissue

• Vascular cambium - gives rise to secondary phloem and secondary xylem. Secondary xylem is produced each year = thickness of perennial and/or wood. This results in annual growth of rings. Each tree ring has cylinder of spring wood (larger cells) and of summer wood.

• Cork cambium - produces cork (dead when mature, protects stem)

• Everything external to the vascular cambium ( secondary phloem, cork cambium, cork) = bark

• What happens if you remove the bark from a tree? __________________

• Extra credit lab/ worksheet is available about counting tree rings.

• Pollinators (Vectors) and

flowers = mutually beneficial relationship

• How do flowers benefit?

(Pollination and seed dispersal)

• How do pollinators benefit?

(Nectar and pollen for food.)

• Color and fragrance advertise for pollinators

• Birds see red/pink

• Bees - smell

• See next Set # 4 For Video Clips of these concepts!

Chapter 29 - The Working Plant

• Sap -watery solutions moving through vascular system.

• In xylem it carries water and nutrients from roots to leaves and stems.

• In phloem it transports sugar already made, from leaves to other parts of plants.

• Sap is made in Spring by converting starch that was made the previous summer into sugars.

• It takes 40 liters of maple tree sap to produce 1 liter of maple syrup.

• Plants get CO2 from air (through stomata),

minerals and H2O from soil,(through root hairs) and O2 from soil.(through stomata).

• A plant releases more O2 from photosynthesis than it consumes by respiration

• Plant nutrition: all minerals that enter a plant root are dissolved in water

• Go through epidermis & cortex of root; plasma membrane of root cells (selectively permeable); to xylem.

• Mycorrhiza (fungi) help in absorption

• Macronutrients-need in large amounts: carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, calcium, potassium, and magnesium

• Micronutrients - need in extremely small amounts: iron, chlorine, copper, manganese, zinc, molybdenum, boron, nickel. Mainly components of enzymes.

• See p. 641-642 for uses of all nutrients

• Deficiencies - quality of soil affects our own nutrition - Corn on left grown in nitrogen rich soil; on right in nitrogen poor soil

• Bacteria help with nitrogen nutrition: 3 types of soil bacteria:

1. Nitrogen-fixing bacteria - converts N2 in air to ammonium

2. Ammonifying bacteria - adds ammonium by decomposing organic matter

3. Nitrifying bacteria - converts soil ammonium to nitrate - plants take this up

• Plants then convert nitrate back to ammonium to make proteins/organics.

• Legumes (soybean, clover, peas, alfalfa) have root nodules that contain nitrogen-fixing bacteria called Rhizobium.

• Symbiotic relationship - bacteria have a place to live and receive carbohydrates/organics from plant. Plants get ammonium ions released into soil.

• Why do some farmers rotate their crops? Ex: One year corn, the next year soybeans? ___________________________________

The Transport of Water:

• Pulled up plant through transpiration (loss of water vapor from plant,) through the stomata

• Cohesion = water molecules stick together, are pulled up together

• Adhesion = water molecules adhere to cellulose molecules in walls of xylem cells

• A continuous string of water molecules move up tube

• Molecules of water break off from the top of the string as they leave the leaf. String is kept tense and pulled upward as long as transpiration continues.

• No energy expenditure by plant

• Called: Transpiration-cohesion-tension mechanism

Chapter 29 continued...

• Transpiration - greatest on sunny, warm, dry and windy days

• Maple tree can lose more than 200 L of water per hour

• Unless rehydrated, plant could eventually die

• Leaf stomata can help plants adjust transpiration rates-controls opening by changing shape

• Open during day and close at night, saving water. May close during day if plant is losing water too fast.

The Transport of Sugars:

• Phloem sap moves in various directions in plant

• Phloem moves sugar from a source (leaf) to a sink (root or fruit)

• Pressure-flow mechanism - the building of water pressure at source end of phloem tube, and the reduction of water pressure at the sink end causes water to flow from source to sink, carrying sugar with it.

Plant Hormones -control plant growth and development - affect division, elongation, differentiation of cells

• 5Major types:

• 1. Auxin-produced by apical meristem, stimulates growth of shoot-causes cells to elongate.

• Ex: Cells elongate (more auxin) on dark side of stem, causes stem to bend on opposite side (toward light)

• Requires certain concentrations: too much = inhibits stem elongation.

• Usually, it inhibits roots (except in high concentrations it can elongate roots.)

• 2. Ethylene - a gas which triggers

aging responses - fruit ripening, dropping of leaves. (See left top photo)

• Why does “one bad apple spoil the whole bunch?’________________

• 3. Cytokinins - growth regulators, promote cell division. In roots, embryos, fruits. Stimulate growth of axillary buds (branches and bushy.)

• Why are cytokinins used by growers of Christmas trees?

• 4. Gibberellins - stimulates cell elongation and cell division in stems. Can influence fruit development. Used in grapes-larger and more farther apart in the cluster. (See left bottom photo)

• 5. Abscisic Acid - slows growth. Ex: seed dormancy, esp. during adverse conditions

• During drought, causes stomata to close during wilting, preventing further water loss

• Photo: desert plants grew from seeds that germinated just after a hard rain - were dormant in parched soil beforehand.

Summary of plant hormones:

The End

Photosythesis

What is matter?

• Matter – anything that occupies space and has mass– Composed of chemical

elements

• Element – cannot be broken down into other substances– 92 natural elements

• EX – oxygen, carbon, copper

– Each element has a symbol from its name

• EX - O, C, Cu

– Essential to life…(96%)• O, C, H, N

– Trace elements…(4%)• Ca, P, K, S

Compounds

• Compound – a substance containing 2 or more elements in a fixed ratio– More common than

elements

NaCl = table salt

H2O = water

Glucose

Sucrose

ATOMS• Atom –

– Indivisible – Greek– Smallest unit of matter

that retains the properties of an element

Atomic Structure – *Nucleus – central core of the atom, contains protons and neutrons

*Proton – positively charged

*Neutron – no charge

*Orbitals - outside the nucleus

*Electron – negatively charged

Attraction between protons and electrons keep the electrons nearby the nucleus.

How is one element different from another

element?• Atomic number – same

as the number of protons– Oxygen has 8 protons

• If the atom is electrically neutral (number of protons = number of electrons) then the atomic number also is the same as the number of electrons.

• Mass number – sum of the numbers of protons and neutrons in a nucleus

Periodic Table of Elements

Isotopes

• Isotopes – elements with the same number of protons and electrons, but a different number of neutrons

Radioactive Isotopes – the nucleus will decay, giving off particles and energy

Chemical Properties of Atoms

• Electrons determine how an atom will behave.• Electrons that are farther from the nucleus have greater energy.• Electron shells – 1st = 2 electrons, 2nd = 8 electrons, 3rd = 8 electrons• If an electron shell is not full the atom is likely to react with other

atoms in a chemical reaction.• If the electron shell is full it is unreactive (chemically inert).

Chemical Bonding

• Ionic bonds – attraction between oppositely charged ions (electron is transferred)– Ions are formed by either

gaining or losing an electron.• Atoms like to have full energy

shells and will easily gain or lose 1-3 electrons to do it.

• Example – Na has 1é in its outer shell and Cl has 7é in its outer shell. Na can lose 1é to become Na+1 and and Cl can gain 1é to become Cl-1 and both will have a full outer shell.

Chemical bonds – formed by atoms trying to fill the outer most electron shell

• Covalent bonds – occur when two atoms share one or more pairs of outer shell electrons.– Molecule – formed by

atoms held together by covalent bonds.

• Chemical Reaction –

changes in the chemical composition of matter

•For a balanced chemical reaction the number of each element must be equal on both sides of the reaction. Reactions cannot create or destroy matter, it can just rearrange it.

Photosynthesis

Photosynthesis is all about

feeding the biosphere

• Photosynthesis converts energy of sunlight into the chemical energy of sugar and organic compounds.– Almost all plants, some protists and some bacteria

• Autotrophs…– An organism that makes all its own organic matter from inorganic nutrients– Self feeders– Require inorganic compounds - CO2, H2O and minerals– Make organic compounds – carbohydrates, lipids, proteins, nucleic acids– producers

• Heterotrophs…– Cannot make organic molecules from inorganic ones– Other feeders– We must eat!– Depend on autotrophs for their organic fuel and material for growth and

repair– consumers

Sites of Photosynthesis

• Chloroplasts – organelle responsible for photosynthesis– Leaves are the major site of photosynthesis (all green parts of a plant

have chlorophyll and chloroplasts and can undergo photosynthesis)

•Double membrane envelope

•Inner membrane encloses the stroma – thick fluid, where sugars are made from CO2

•Thylakoids – sacs suspended in the stroma, stacked in grana, where the chlorophyll molecules that capture the light energy are stored

Parts of the leaf…

• Mesophyll – cells making up the green tissue on the interior of the leaf– Palisade mesophyll –

upper portion, densely packed

– Spongy mesophyll – lower portion, air spaces

• Stomata – openings through which CO2, H2O and O2 gases are exchanged (most H2O comes up from the roots)

Photosynthesis Chemical Reaction

• Reactants = 6 CO2 and 6 H2O

• Products = C6H12O6 and 6 O2

• Electrons are added to CO2 to produce sugar

• Sunlight provides the energy to split the H2O molecules and release O2 into the atmosphere

Photosynthesis:A Simple Summary

1. Light Reactions• Convert solar to

chemical energy

• Synthesize ATP (energy storage) and NADPH (electron carrier)

2. Calvin Cycle (Dark Reactions)

• Makes sugar from CO2

• Uses ATP and NADPH from light reactions

Light Reactions

• Sunlight is radiation or electromagnetic energy.• We are able to see only light that is reflected from an

object.• EX – green leaves absorb red-orange and blue-violet light;

therefore, reflecting green light. Chloroplasts convert the absorbed energy.

Chloroplast Pigments Found in photosystems…

1. Chlorophyll a – absorbs blue-violet and red light

– Participates directly in the light reactions

2. Chlorophyll b – absorbs blue and orange light

– Helps light reactions by increasing the range of light that can be absorbed

3. Carotenoids – absorb blue-green light

– Absorb and dissipate excessive light that may damage chlorophyll a

Photosystems and Light• Photon – fixed

quantity of light energy

• Pigment molecules absorb photons of light that “excite” the electrons to a higher energy state

• As the electron “falls” back to the normal state is releases energy as heat or light energy

• Photosystems – have clusters of pigment molecules that act as antennae for photons of light.

• Photons of light “jump” from pigment to pigment until it reaches the Reaction Center containing chlorophyll a.

• Next to the reaction center is the primary electron acceptor which traps the light excited electron energy into ATP or NADPH.

Two Types of Photosystems

1. Water splitting photosystem – Light energy to extract

electrons from water Releases O2 as a waste

product

2. NADPH producing photosystem Produces NADPH by

transferring light excited electrons from chlorophyll to NADP+

•An electron transport chain connecting the two photosystems releases energy used to make ATP

• Light reactions as seen in the thylakoid membrane.• Electron transport chain pumps H+ ions across a

membrane.• ATP synthases use the energy stored by the H+

gradient to make ATP.

Calvin Cycle(Dark Reactions)

Calvin Cycle

• It is a cycle because the starting material is regenerated with each turn of the cycle.

• Inputs…– CO2, ATP and NADPH

• Outputs…– Glyceraldehyde 3-

phosphate• Raw material to make

glucose and other organic molecules

C3 vs. C4 vs. CAM

• C3 Plants – use CO2 directly from the air

– EX – soybean, wheat, oats, rice…

– Dry weather can decrease the rate of photosynthesis and crop productivity because stomata are closed to prevent water loss and no CO2 gas exchange occurs.

• C4 Plants – use an enzyme to incorporate CO2 – EX – corn, sorghum, sugarcane– Save water without slowing photosynthesis– When hot the stomata are closed to prevent water loss– Continues sugar production by using an enzyme to incorporate CO2

into a 4 C compound instead of the normal 3 C compound.

•CAM Plants – opens stomata at night to let in CO2 and to prevent water loss

–Ex – pineapple, cacti, succulents–Once the CO2 is inside the leaf it forms a 4 C compound–Bank CO2 at night and release it to the Calvin Cycle during the day

Photosynthesis Review

Greenhouse Effect – warming induced by CO2

CellularRespiration

Energy Cycle

• Photosynthesis – uses light energy to make organic molecules– Chloroplasts– Chlorophyll– Producers

• Respiration – harvests energy stored in sugars and organic molecules – Mitochondria– Consumers

CO2 + H2O C6H12O6 + O2

Types of Energy

• ENERGY – capacity to do work

– Kinetic Energy – energy of motion

– Potential Energy – energy because of its location or arrangement

– Conservation of Energy – energy can neither be created nor destroyed

• ENTROPY – measure of disorder or randomness

• Chemical Energy – energy stored in the chemical bonds of molecules; a form of potential energy