Plantae

Seed Plants Vascular Plants

• Formation of vascular tissue – Xylem (water) – Phloem (food) – True leaves, roots, and stems • Lignin • ______generation dominate Alternation of Generation Alternation of Generation • Sporophyte dependent on gametophyte – mosses • Large sporophyte and small independent gametophyte – ferns • Gametophyte dependent on sporophyte – seed plants Why be Sporophyte Dominant? • Reduced mutations – UV light harmful to DNA – Diploid (2n) form copes better with mutations • two alleles Why Retain Gametophyte Generation? • Ability to screen alleles – doesn’t require a large amount of energy • Sporophyte embryos rely on some gametophyte tissue Seeds • A seed is a sporophyte in a package – spores are only single cells – packaged with food • All seed plants are ______(more than one kind of spore) – megasporangia – microsporangia From Ovule to Seed Develops from megaspore

Whole structure Embryo, food supply, protective coat Overview of Seed Plants • Produce Seeds – Can remain dormant for years – Pollination replaces swimming sperm • Gametophyte generation reduced – Gymnosperms lack antheridium – Angiosperms lack both archegonium and antheridium Phylogeny Gymnosperms (Naked Seed) • Division: Cycadophyta • Division: Ginkgophyta • Division: Gnetophyta • Division: Coniferophyta Ginkgophyta • Ginkgo or Maidenhair Tree • Characteristic leaves • Only one species • Only ______are planted Cycadophyta

• Cycads • Palm-like plants – Sago Palms • Leaves in cluster at top of trunks • True ______Gnetophyta • 3 Genera • Ephedra • Mormon Tea – ______• raises heart rate • raises blood pressure Coniferophyta

Coniferophyta

• Pine tree is the sporophyte generation • Contains both male and female cones – Pollen (______) cones (low in tree) • produces pollen – Ovulate cones (high in tree) with scales • produces seeds Pine Life Cycle • No Antheridium (microsporangia) produce pollen grain (4 cells) –2 prothallial cells –1 generative cell »produces 2 sperm –1 tube cell –______for dispersal Pine Life Cycle • Ovule in a ovulate cone – integument (seed coat) (2n) – megasporangia or nucellus (nutrition) (2n) – 4 ______from female gametophyte (3 die) • develops into female gametophyte –archegonium with eggs (n)

Angiosperms Angiosperm Flower • Sepals • Stamen • Petals – Anther – Filament • Receptacle (part of the stem) • Carpel – Stigma – Style – Ovary with ovule Angiosperm Life Cycle Angiosperm Life Cycle • No Antheridium (microsporangia - diploid) • produce pollen grain –1 ______cell »produces 2 sperm –1 tube cell Angiosperm Life Cycle • Ovule in Ovary – megasporangia – produces 4 megaspores (3 die) • remaining one develops into female gametophyte called the ______Angiosperm Life Cycle • Embryo sac (Female Gametophyte) consists of: – 7 cells (eight nuclei) due to 3 mitotic divisions • 3 ______• 2 polar nuclei (one cell) • 2 ______• 1 egg Angiosperm Life Cycle • Double fertilization – one sperm unites with egg – one sperm unites with polar nuclei • develops into endosperm (3n) • Fruit and Seed development – ovule = seed – ovary = fruit Angiosperm Life Cycle Cross Pollination

• Most flowers do not self-pollinate – stamen and carpal may develop at different times – stamen and carpal may be arranged in flower to avoid contact Angiosperm Radiation • Begins the Cenozoic era (65 mya) • Most closely related to the Gnetophyta • ______– the mutual influence of two species on each other – plants and animals (insects, birds, bats) Pollination Dispersal The Global Impact

• Transformed atmosphere – reduced carbon dioxide – cooled the earth • Nonrenewable/Renewable resource Plant Structure And Growth The Plant Body is Composed of Cells and Tissues •Tissue systems (Like Organs) –made up of tissues •Made up of cells Plant Tissue Systems • ______Øphotosynthesis Østorage Øsupport • ______Vascular Tissue System Øconduction Øsupport • ______Dermal Tissue System ØCovering Dermal Tissue System • Epidermis – Single layer, tightly packed cells – Complex Tissue – Does different things in different areas (roots vs. leaves) – usually transparent – secretes cuticle • ______Periderm – – replaces epidermis in woody plants – protection • ______Root System – Tap Root – Lateral Roots • ______Shoot System – Stems • Nodes (leaves are attached) • Internodes – Leaves • blades • petioles – Buds • Terminal (apical) Plant • Axillary Systems Plant Growth

• ______Meristematic Tissue –generates cells for new growth (like stem cells in animals) •apical meristems •lateral meristems Apical Meristems • increases length called primary growth –______Protoderm - gives rise to dermal tissue –______Ground Meristem - gives rise to ground tissue –______- gives rise to vascular tissue Lateral Meristems • increases girth called secondary growth –______- produces secondary xylem and secondary phloem –______Cork Cambium - produces cork (outer most layer of bark) Pine Tree w/ 8 Cotyledons!

The Root System • Functions – anchor plant – absorb minerals, water and nutrients – store food • Systems – ______- one large root with smaller lateral roots (dicots) – ______Fibrous roots - threadlike roots (monocots) Root Tissue • Protoderm - gives rise to the epidermis • Ground Meristem – Cortex (external to vascular tissue) • Procambium - gives rise to the ______Stele (the vascular tissue of a root or stem) – xylem and phloem – may include pith (parenchyma cells surrounded by vascular tissue) Dicot Root vs. Monocot Xylem (larger, in red)

Endodermis

Phloem (smaller, greenish)

Pericycle – one layer IN from endoderm, gives “Pith” – central core of rise to lateral roots parenchyma cells surrounded by xylem and phloem Modified Roots

• Food Storage • Pnematophores – carrots, sweet – mangroves potatoes, yams • Aerial Roots • Water Storage – orchids – pumpkin family • Buttress Roots • Propagative – tropical trees Roots • Haustoria – cherries, pears – dodder Shoot System Stems (Primary Growth) • Protoderm - gives rise to the epidermis • Procambium - gives rise to the stele – xylem and phloem in vascular bundles •dicots - found in ring •monocots - scattered throughout – includes “pith” in dicots • Ground Meristem – Cortex ______– stele (vascular tissue) divided into strands in stems and leaves

Sclerenchyma cells

Phloem Xylem Dicot Stem Vs. Monocot (35.16)

Vascular Bundle

Ground Tissue (Pith) (Cortex)

How can you tell root from stem? Stems (Secondary Growth) • Occurs to increase girth (thickness) – Vascular Cambium • produces secondary xylem and secondary phloem – Cork Cambium • produces cork and phelloderm (thin layer of parenchyma cells) • together these structures are called periderm (Cork Cambium, cork, phelloderm) Secondary Growth

Derivative

Vascular cambium

Secondary Growth of a Stem Secondary Growth of a Stem (Inside to Outside) • Pith • Secondary Phloem • Primary Xylem • Primary Phloem • Secondary Xylem • Cortex (wood) • Phelloderm • Vascular • Cork Cambium

Cambium Periderm • Cork (outer layer of bark) Older, inner layers of 2° Xylem – no longer transport water

Younger, outer layers of 2° Xylem still function in transport

All tissue outside vascular cambium

Missing cortex and phelloderm!

______(Early) growth occurs more quickly. Cells are large and thin walled and have less strength.

Summerwood (Late) growth occurs more slowly. Cells are thicker, more dense, and stronger. Modified Stems • ______- horizontal stems above the ground (strawberries) • Rhizomes - horizontal stems below the ground (Irises) • Tubers - swollen areas of rhizomes or stolons (Potatoes) • Bulbs & Corms - vertical shoots under ground (onions, garlic w/ mod storage leaves) • ______Cladophylls - cactus pads Leaf Structure Leaves • Epidermis – ______Stomata - openings on underside of leaf – Guard Cells - surround stomata – Cuticle - waxy coating excreted by epidermis • Mesophyll - middle of leaf – ______Palisade Layer - photosynthesis – Spongy layer - gas exchange Modified Leaves • ______Tendrils - attachment • Bracts –modified leaves that surround a group of flowers • Spines - protection • Storage Leaves - succulents Uptake of Nutrients ______Hydroponic cultures used to determine which chemical elements are essential.

17 essential elements needed by all plants NEED TO KNOW THE CHART!!! Soil • Develops from weathered rocks – Anchors plants – Provides water – Provides dissolved minerals Soil Texture • Pertains to sizes of soil particles – includes the following: • sands (0.02 - 2 mm) • silt (0.002 - 0.02 mm) • clay (less than 0.002 mm) • Loams (40/40/20) Control Systems in Plants Plant Hormones

• Coordinates growth • Coordinates development • Coordinates responses to environmental stimuli Auxins

• Stimulates stem elongation • Stimulates root growth • Stimulates differentiation and branching • Stimulates development of fruit • Stimulates apical dominance • Stimulates phototropism and gravitropism Auxin Control • Auxin stimulates growth • Auxin block on right causes cells to elongate and the plant bends left • Auxin block on left causes cells to elongate the the plant bends right ______Acid Growth Hypothesis • Proton pump stimulated by auxin lower pH of wall • H+ activates Enzyme • Enzyme breaks hydrogen bonds in cellulose • Wall takes up water and elongates Auxin Others • Promotes secondary growth by stimulating vascular cambium and secondary xylem • Promotes adventitious root at the base of a cut stem • Promotes fruit growth without pollination (seedless tomatoes) Cytokinins • Works with Auxin: – more cytokinin - shoot buds develop – more auxin - roots develop • Stimulates germination • Delays Senescence Gibberellins • Promotes seed and bud germination • Promotes stem elongation • Promotes leaf growth • Stimulates flowering and fruits – (with auxin) Ethylene • Promotes fruit ripening • Controls Abscission (causes leaf loss) Phytochromes

• Function as photoreceptors / red (660nm) to far red (730nm) • Activates kinases (regulatory proteins) Red vs. Far Red Response Why plants are • Food! important? • Humans have domesticated plants for 13,000 years. • ____ of all the calories consumed by humans come from six crops: Wheat, Rice, Maize, Potatoes, Cassava, and Sweet Potatoes. • Also, we use plants to feed cattle, 5-7kg to produce 1 kg of beef. Pyramid of Net Productivity Plants remove CO2 •_____25% of all US Prescription Drugs contain one or more active ingredients from plants. •____50% earth’s species will become extinct within the next 100 years (larger than the Permian or Cretaceous) •Only 5,000 of 290,000 species have been studied. •3-4 species per hour, 27,000 per year! Cinchona tree

• Bark contains ______• Grows in the Andes in peru • Used since the early 1600’s to treat malaria Aspirin • Acetylsalicylic acid or ASA • Dates back to 3000 B.C. • Greek Physician Hippocrates prescribed it. • From Willow______trees and other Salicylate-rich plants (leaves and bark) • Scientists at Bayer began investigating acetylsalicylic acid as a less-irritating replacement for standard common salicylate medicines. By 1899, Bayer named it this Aspirin Ecology Hadley Cell Hadley Cells

Biomes

Charles Darwin • Differential Reproductive Success - Adaptation • 1859 Origin of Species. • Romanes – Neodarwinism & The Modern Synthesis (Genetics) Evolution in the Lab Allopatric Speciation Sympatric Speciation Hugo De Vries

• Evening Primrose

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