domain bacteria domain archaea domain eukarya common ancestor kingdom: plants domain eukarya
TRANSCRIPT
DomainBacteria
DomainArchaea
DomainEukarya
Common ancestor
Kingdom: PlantsDomain Eukarya
Plant evolutionIt is thought that life evolved in the seas– 1st photosynthetic organisms were aquatic green algae
• 500 mya land plants evolved– special adaptations for life on dry land >protection from drying = desiccation >waxy cuticle
>gas exchange (through cuticle)-stomates
>water & nutrient conducting systems
-xylem & phloem>protection for embryo
-seeds
Plant Diversity
Bryophytesnon-vascularland plants
Pteridophytesseedless
vascular plants
Gymnospermpollen &
“naked” seeds
Angiospermflowers & fruit
pollen & seeds
vascular system = water conduction
mosses ferns
conifersflowering plants
colonization of land
Tracheophytes
xylem cells = tracheidsAncestral Protist
flowers
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
First land plants• Bryophytes: mosses & liverworts
– non-vascular• no water transport system• no true roots
– swimming sperm• flagellated sperm
– lifecycle dominated by haploid gametophyte stage• fuzzy moss plant you are
familiar with is haploid– spores for reproduction
• haploid cells which sprout to form gametophyte
diploidhaploid
Where mustmosses live?
First vascular plants• Pteridophytes: ferns
– vascular• water transport system• xylem, phloem, roots, leaves
– swimming sperm• flagellated sperm
– life cycle dominated by sporophyte stage• leafy fern plant you are familiar
with is diploid• fragile independent gametophyte
(prothallus)
– spores for reproduction• haploid cells which sprout
to form gametophyte
diploid
Where mustferns live?
haploid
diploid
Alternation of generations
haploid
produces male & female gametes
archegonia
antheridia
First seed plants
– Gymnosperm: conifers• vascular• seeds
– naked seeds (no fruit)
• pollen– contain male gametophyte
• life cycle dominated by sporophyte stage– coniferous trees are diploid– reduction of gametophyte protects delicate egg &
embryo in protective cones» protected from drought & UV radiation
Early Gymnosperm: ginkgo & Cycad
Cones & naked seeds
Why is pollen important?
• Pollen eliminated need for water fertilization– spreads through wind
& animals
• Why does it irritate noses? – See the spikes?
First flowering plants• Angiosperm: flowering plants
– vascular– flower
• specialized structure for sexual reproduction
– seeds within fruit-protection & nourishment for seed!– pollen– life cycle dominated by
sporophyte stage• trees & bushes are diploid• microscopic gametophyte
Anther
FilamentStamen
StigmaStyleOvary
Carpel
Sepal
Petal
Ovule
Flower• Modified shoot with 4 rings
of modified leaves– sepals– petals– stamens
• male
– carpel• female
sepalspetals
stamens
carpel
Identify the flower structures…
seed coat
endosperm(3n)
cotyledons
embryo (2n)
cotyledons = “seed” leaves,first leaves of new plantcotyledons = “seed” leaves,first leaves of new plant
Angiosperms: fruiting plants• Have fruits in many
forms• Seeds contain plant
embryo• Embryo consists of
cotyledons, endosperm, hypocotyl & epicotyl
• Seed offers…– protection for embryo– stored nutrients for
growth of embryo
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
Comparison of Monocots & Dicots
Acknowledgements
• With thanks to
• Kim Foglia & her website “Explore Biology”– Specifically the power point from which this
was drawn– 13 Ch29Plants2008.ppt
Also:
http://www.daylilies.org/ahs_dictionary/monocotseedlingnew.jpg