Plants 1 Introduction to Plants (Student Copy)

8/2/2019 Plants 1 Introduction to Plants (Student Copy)

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Evolution of Land Plants

500 mya land plants evolvedspecial adaptations for life on dry land

protection from drying = desiccation

waxy cuticle

gas exchange (through cuticle)

stomates

water & nutrient conducting systems from roots/soil to leaves

xylem & phloem

protection for embryo

seeds


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Plant Diversity

Bryophytes

non-vascularland plants

Pteridophytes

seedlessvascular plants

Gymnosperm

pollen &naked seeds

Angiosperm

flowers & fruit

pollen & seeds

vascular system = water conduction

mosses ferns

conifersflowering plants

colonization of land

Tracheophytes

xylem cells = tracheidsAncestral Protist

flowers

monocot1 seed leaf

dicot2 seed leaves


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Animal vs. Plant life cycle

diploidmulticellular

individual2n

diploidmulticellularsporophyte

2n

haploidmulticellulargametophyte

1n

haploidunicellulargametes

1n

gametes1n

Animal Plant

alternation of generations

meiosis

fertilization

mitosis

mitosismitosis

fertilization

mitosis

no multicellularhaploid

meiosis

spores1nzygote 2n

zygote 2n


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diploidhaploid

Bryophytes: 1st land plants

Where mustmosses live?

Bryophytes: mosses & liverworts vascular system?

No!non-vascular no water transport system no true roots

dominant stage? haploid gametophyte stage reduced, dependent sporophyte fuzzy moss plant you are familiar

with is haploid reproduction?

swimming sperm

flagellated

spores

sprout to form gametophyte


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Bryophytes: mosses & liverworts


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Peat BogPeat Moss


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Pteridophytes: 1st vascular plants diploid

haploid

Pteridophytes: ferns vascular system? Yes!vascular

water transport system

xylem, phloem, roots, leaves

dominant stage?

diploid sporophyte stage

fragile, independentgametophyte (prothallus)

reproduction? swimming sperm

flagellated

spores

sprout to formameto h te

Where mustferns live?


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Pteridophytes: FernsSelaginella Psilotum

Horsetails Ferns


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Alternation of generations

Fern gametophyte (1n) homospory: male & female gamete

production on same plant

archegonia

antheridia


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Early Pteridophytes: Tree Ferns

Carboniferous forest 290-350 mya

Forests of seedless plants decayed into deposits of coal & oil

FossilfuelsI get it!


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Pteridophytes: Tree ferns

frondsfiddleheads

With frondslike these who

needs enemies!


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Gymnosperm: conifers vascular system?

Yes!vascular xylem, phloem, roots, leaves

dominant stage?

diploid sporophyte stage reduced (microscopic) gametophyte reduction of gametophyte protects delicate egg &

embryo in protective sporophyteprotected from drought & UV radiation

heterospory: male vs. female gametophytes

reproduction? seedsnaked seeds (no fruit)

pollen

contain male gametophyte

First seed plants: Gymnosperm

Where canconifers live?


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Early Gymnosperm: cycads


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Gymnosperm: conifers


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Cones & naked seeds


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First flowering plants

Angiosperm: flowering plants vascular system? Yes!vascular

dominant stage? diploid sporophyte stage

reduced (microscopic) gametophyte

protects egg & embryo

heterospory: male vs. female gametophytes

reproduction?

flowersexual selection: attract pollinators

seeds inside fruitsexual selection: attract seed spreaders

pollen contain male gametophyte


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Angiosperm: flowering plants


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pollen

grains

new sporophytein seed (diploid)

ovary sac

3n endosperm

2n zygote

doublefertilization

female gametophyte =ovary sac (haploid)

male gametophyte =

pollen grain (haploid)

sperm nuclei traveldown pollen tube

2n embryo

polarnuclei

eggcell

Angiosperm life cycle


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Anther

FilamentStamen

Stigma

Style

Ovary

Carpel

Sepal

Petal

Ovule

sepals

petals

Flower

Modified shoot with 4 ringsof modified leaves

sepals

petals stamens

male

carpel / pistil

female stamens

carpel

adaptations through mutations


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Flower variations


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Co-evolution: flowers & pollinators

How a bee sees a flowerinsects seeUV light = a bulls-eye to the nectar


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Angiosperm: fruiting plants


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Other fruits


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Seed & Plant embryo

Seed offers protection for

embryo

stored nutrientsfor growth ofembryo

seed coat

endosperm(3n)

cotyledons

embryo (2n)

cotyledons = seed leaves,

first leaves of new plant


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Monocots & dicots

Angiosperm are divide into 2 classes dicots (eudicot)

2 cotyledons (seed leaves)

leaves with network of veins

woody plants, trees, shrubs, beans

monocots

1 cotyledon

leaves with parallel veins grasses, palms, lilies


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Documents

Plants 1 Introduction to Plants (Student Copy)