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AP Biology

AP Biology 2007-2008

DomainEubacteria

DomainArchaea

DomainEukarya

Common ancestor

Kingdom: PlantsDomain Eukarya

AP Biology

Evolution of Land Plants 500 mya land plants evolved

special adaptations for life on dry land protection from drying = desiccationwaxy cuticle

gas exchange (through cuticle)stomates

water & nutrient conducting systems from roots/soil to leavesxylem & phloem

protection for embryoseeds

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Plant Diversity

Bryophytesnon-vascularland plants

Pteridophytesseedless

vascular plants

Gymnospermpollen &

“naked” seeds

Angiospermflowers & fruit

pollen & seeds

vascular system = water conduction

mosses fernsconifers

flowering 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 Bog“Peat 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, independent

gametophyte (prothallus) reproduction? swimming sperm flagellated

spores sprout to form

gametophyte

Where mustferns live?

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Pteridophytes: FernsSelaginella Psilotum

Horsetails Ferns AP Biology

Alternation of generations Fern gametophyte (1n)

homospory: male & female gamete production on same plant

archegonia

antheridia

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diploid

Alternation of generations

haploid

produces male & female gametes

archegonia

antheridiaAP Biology

Early Pteridophytes: Tree Ferns

Carboniferous forest – 290-350 myaForests of seedless plants decayed into deposits of coal & oil

Fossil fuels…I get it!

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Pteridophytes: Tree fernsfrondsfrondsfiddleheadsfiddleheads

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: ginkgo

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Early Gymnosperm: cycads

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Gymnosperm: conifers

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Cones & naked seeds

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male

female

male (pollen) cones

female cones

sporangium & pollen

pine embryo AP Biology

First flowering plants Angiosperm: flowering plants

vascular system? Yes! vascular

dominant stage? diploid sporophytestage reduced (microscopic) gametophyte

protects egg & embryo heterospory: male vs. female gametophytes

reproduction? flower

◆sexual selection: attract pollinators seeds inside fruit

◆sexual selection: attract seed spreaders pollen

contain male gametophyte

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Angiosperm: flowering plants

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pollengrains

new sporophytein seed (diploid)

ovary sac

3n endosperm

2n zygote

doublefertilization

female gametophyte =ovary sac (haploid)

male gametophyte =pollen grain (haploid)

sperm nuclei travel down pollen tube

2n embryo

polarnuclei

eggcell

Angiosperm life cycle

AP Biology

Anther

FilamentStamen

StigmaStyleOvary

Carpel

Sepal

Petal

Ovule

sepalspetals

Flower Modified shoot with 4 rings

of modified leaves sepals petals stamens male

carpel / pistil female stamens

carpel

adaptations through mutations AP Biology

Identify the flower structures…

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Flower variations

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Co-evolution: flowers & pollinators

How a bee sees a flower…insects see UV 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 nutrients for growth of embryo

seed coat

endosperm(3n)

cotyledons

embryo (2n)

cotyledons = “seed” leaves,first leaves of new plantcotyledons = “seed” leaves,first leaves of new plant AP Biology

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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Any Questions??