Plant Classification

Alternation of generations Sporophyte (diploid) Begins when sperm fertilizes egg (zygote) Diploid zygote divides by mitosis to create a mature sporophyte Meiosis produces haploid cells called spores Haploid spores released

Alternation of generations Gametophyte (haploid) Begins with spores created by meiosis Spore grows into gametophyte Male gametophyte creates sperms Female gametophyte creates eggs Sperm & egg create diploid zygote (process repeats)

Group 1: Seedless, Nonvascular Plants Live in moist environments Liverworts Hornworts Mosses

Mosses Nonvascular, seedless Grow low to ground to retain moisture Lack true leaves Leaf-like structures only 1 cell thick Rhizoids anchor into soil Early inhabitant of new ecosystems (succession)

Moss Life Cycle Gametophyte phase Sporophyte phase Dominant stage Carpet of moss growing near ground Archegonium: produces female egg Antheridium: produces male sperm Sperm swims through water to fertilize egg Sporophyte phase Stalk grows up from the gametophyte Sporangia houses haploid spores Spores land and new gametophyte grows Moss Life Cycle See appendix B in your text book

. . . . . 1) Moss gametophytes grow near the ground (haploid stage) 2) Through water, sperm from the male gametophyte will swim to the female gametophyte to create a diploid zygote 3) Diploid sporophyte will grow from the gametophyte where the zygote is located 4) Sporophyte will create and release haploid spores . . . . . sporophyte gametophyte

. . . . . 5) Spores land and grow into new gametophytes 6) The process repeats . . . . . ground gametophyte

Group 2: Seedless, Vascular Plants Vascular system allows nutrient transport to greater heights Club mosses Horsetails Ferns

Ferns Seedless, vascular plants Vascular: allows taller growth Rhizoids: underground stems draw nutrients Fronds: leaves uncurl sporangia on underside Sori: clusters of sporangia

Fern Life Cycle Sporophyte phase Gametophyte phase Dominant stage Sporangia produces haploid spores Spores released into air Gametophyte phase Spore grows into prothallus Archegonium: produces female egg Antheridium: produces male sperm Sperm swims to egg Zygote begins sporophyte stage See appendix B in your text book

. . . . 1) Sporophyte creates and releases haploid spores Adult Sporophyte (diploid) ground

2) Spores land in the soil . . . . ground

3) From the haploid spores, a prothallus (haploid gametophyte) grows in the soil -- Rhizoids anchor Let’s zoom in ground

4) Sperm swim through water from the antheridium to the archegonia Let’s zoom back out

5) Diploid sporophyte (fiddlehead) grows from the prothallus -- prothallus eventually dies ground

. . . . 6) Fiddlehead uncurls into fronds of ferns. 7) Cycle repeats -- Sporangia creates spores to be released . . . . ground

Group 3: Seed producing, Vascular Plants Gymnosperms Cycads Ginko Conifers Angiosperms

Group 3: Seed producing, Vascular Plants 1) Seed plants don’t depend on water to reproduce Pollen (contains sperm) combines with egg Egg hardens into a seed 2) Nourishment and protection Nourish: Nutrients inside seed for the embryo Protection: Hard shell 3) Allow dispersal Carried by wind, water, animals

Group 3: Seed producing, Vascular Plants Type 1: Gymnosperms Seeds not enclosed in a fruit produced inside cones Cone = reproductive structure Male cones: produce pollen Female cones: produce eggs and seeds

Group 3: Seed producing, Vascular Plants Gymnosperm example: Conifers Cone plants Needle-like leaves Common to lumber industry Evergreen, Pine, Redwood, Cedar

Conifers Seed advantages Conifers: woody cone houses seeds Don’t depend on water Protects & nourishes embryo Allow plants to grow in new locations Conifers: woody cone houses seeds Male cones: produce pollen Female cones: produce egg Pines, redwoods, spruce, cedar

Conifer Life Cycle Sporophyte phase (dominant) Cones grow on tree Female cones Megaspores inside archegonia (gametophyte) Male cones Microspores (gametophyte) released from antheridia sticks to archegonium Pollen tube grows from pollen Sperm travels down pollen tube (zygote/seed created) Sporophyte stage restarts

1) Male and female seed cones grow in adult sporophytes

2) Pollen grains released from the male seed cones 2) Pollen grains released from the male seed cones -- Pollen is the male gametophyte Let’s zoom into the female seed cone

3) Pollen grain sticks to the female ovule 4) Pollen tube grows from the male spore 5) Two nuclei transfer into female spore - one fertilizes the egg 6) Diploid embryo develops (sporophyte stage restarts)

7) After seeds harden, the cone reopens and the seeds are released

8) Seed will land ground

9) Seedling grows into (sporophyte)…the cycle repeats ground

female male

Group 3: Seed producing, Vascular Plants Type 2: Angiosperms (flowering plants) Flower = reproductive structure Protects gamete and fertilized eggs Seeds enclosed in a fruit Fruit: Plant ovary Often attract animals to disperse the seeds inside

Angiosperm types (flowering plants) 2 groups: Monocots and Dicots (based on seed type) Cotyledon: embryonic leaf Monocots: embryo with 1 seed leaf Dicots: embryo with 2 seed leaves

Monocots vs. Dicots

Angiosperm Life Spans Three Life Span Types: Annuals Biennials 1 year: Mature…produce seeds…die Biennials 1st year: produces short stem, low growth leaves, food reserves 2nd year: taller stem, leaves, flowers, seeds Perennials Live for more than 2 years

Flowers Reproductive structure of flowering plants Sepals outer ring of leaves protection Petals Inner ring of leaves Brightly colored to attract pollinators Open petals & sepals reveal male and female structures

Flowers Female Carpel Male Stamen Inner most part Ovary: within the base (female gametophyte) Style: long stalk Stigma: sticky tip, collects pollen Male Stamen Surrounds carpel Filaments: long stalks Anther: produces pollen (male gametophyte)

1) Flower matures and opens

2) Microspores (male gametophytes) created in the anthers

In the Anthers Meiosis makes 4 microspores In each microspore Nucleus splits in two 1 nucleus: forms pollen tube 1 nucleus: splits again to make 2 more nuclei 1 nucleus: fertilizes the egg 1 nucleus: fuses to make endosperm

3) Microspores continue to develop

4) Ovaries divide by meiosis to create megaspore

In the Ovules Meiosis makes 4 megaspores (only 1 survives) In megaspore Mitosis creates 8 nuclei 1 nucleus: egg cell 2 nuclei: form embryo sac 5 nuclei: disintegrate

Microspore lands on stigma

Microspores (pollen) released

Microspores (pollen) land on the stigma

Pollen tube and 2 nuclei transfer into the ovule . .

5 & 6) Pollen tube grows from pollen Two sperm nuclei follow down the pollen tube

7) Double fertilization: 1 sperm nuclei fuses w/ egg (zygote created) 1 sperm nuclei fuses w/ the embryo sac (endosperm created)

8) Ovule hardens to form seed

Fruit Production In the seed Embryo Endosperm Surrounding ovary grows into a fruit Fruit attracts animals to eat and spread the seeds Fruit seeds in fox droppings

9) Seed germinates…cycle repeats