Highlights of Plant Evolution

Alternation of Generation Both a __________ haploid and __________ diploid stages in the life cycles.

Classification of Seedless Plants (Kingdom: Plantae) Nonvascular Seedless plants –_____________ Mosses –Hepatophyta Liverworts –Anthocerophyta Hornworts Vascular Seedless plants –Lycophyta Club mosses –Psilophyta Whiskferns –Spenophyta Horsetails –_____________ Ferns Kingdom Plantae – currently defined as plants with embryos) We will treat all of these as separate “divisions”

Bryophytes - Nonvascular Seedless Plants Plant is a thallus (no vascular tissue) –no true leaves, roots, stems __________/_________: –Gametophyte (antheridium and archegonium) –sporangium (produces spores) GametophyteSporophyte

Hepatophyta Liverworts –Two forms __________ (80%) __________ (20%)

Hepatophyta Liverworts –Reproduction Asexual (_______________) sexual

Anthocerophyta ____________

Bryophyta Mosses

Moss gametophytes grow more vertically than horizontally Bryophyta Essay!

Pteridophytes - Vascular Seedless Plants Formation of vascular tissue –__________ (water) –__________ (food) –True leaves, roots, and stems Lignin (chemical in cell wall) Sporophyte generation dominate Sperm with flagella

Lycophyta Lycophytes –true leaves Microphylls – small, usually spine shaped leaves with a single vein. –true stems –true roots –____________ leaves that produce spores

Psilophyta

Sphenophyta Horsetails –true leaves microphylls –true stems silica –true roots

Fern Life Cycle Essay!

Plantae Seed Plants

Vascular Plants Formation of vascular tissue –Xylem (water) –Phloem (food) –True leaves, roots, and stems Lignin ____________ generation dominate

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 Whole structure Develops from megaspore 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

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 Petals Receptacle (part of the stem) Stamen –Anther –Filament Carpel –Stigma –Style –Ovary with ovule

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

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)