5 derived characteristics in land plants (not in ancestors)
Apical meristems localized areas of cell division in shoot &
tips Alternation of generations separate slide Walled spores
produced in sporangia tough wall resists drying 2n spore mother
cells go through meiosis to produce 4 haploid spores Multicellular
gametangia Archegonium (female) produces haploid egg & keeps it
Antheridium (male) produces & releases sperm Multicellular,
dependent embryos develop w/in archegonium from zygote Derive
nutrition from female parent tissue with specialized placenta- like
cells
Slide 3
2 more traits that evolved in many plant groups Cuticle Made of
waxes on surface of epidermal cells Protection Secondary compounds
Repel herbivores & parasites Absorb UV radiation Attract
symbionts
Slide 4
Basic Life Cycle of Plants Alternation of Generations
Bryophytes Non-vascular whole body can absorb water Gametophyte
is larger (dominant) stage Sporophyte dependent on gametophyte No
true leaves Flagellated sperm Mosses require water for
fertilization. Why?
Slide 7
Moss Life Cycle p. 581
Slide 8
Pterophytes Seedless vascular plants Ex ferns Sporophyte larger
stage True roots & leaves w/ horizontal stem Sporangia on
leaves called sporophylls Homosporous one kind of spore (bisexual
gamete egg & sperm) Heterosporous female spore (megaspore)
female gametophyte egg Male spore (microspore)male gametophyte
sperm
Slide 9
Fern Life Cycle p. 585
Slide 10
Vascular Seed Plants Common traits Seeds Integument seed coat
Female gametophyte food supply Embryo sporophyte baby plant
Advantage of seeds Consists of embryo and food supply contained in
protective coat Better resist harsh environments Disperse offspring
more widely
Slide 11
Reduced gametophytes spores retained in sporangia, develop into
gametophytes Heterospory Megasporangium produce one megaspore &
female gametophyte Microsporangium produce many microspores &
male gametophytes Ovules contains female gametophytes Pollen
contain male gametophytes transferred to female part of plant and
will germinate into a pollen tube that finds the ovule and egg
Slide 12
Gymnosperms Bear naked cones seeds are exposed on modified
leaves that usually form cones Pollen cones produce pollen Ovulate
cones produce eggs Coniferophyta pines, firs, redwoods
Slide 13
Pine Life Cycle p. 597
Slide 14
Angiosperms Anthophyta - Flowering plants used for sexual
reproduction Megasporangium megaspore megagametophyte in ovule (all
enclosed in ovary of flower) Microsporangium microspore
microgametophyte in anther of flower Fruits - mature ovary seed
develops from ovules after fertilization, the wall of the ovary
thickens Ex tomato, grapefruit, nectarine, milkweed, walnut
Pollination required for transfer of pollen from flower to the
female sex organs of another flower
Slide 15
Double Fertilzation One sperm fertilizes the egg cell and the
other sperm combines with the two polar nuclei of the large central
cell of the embryo sac. Result - One sperm nucleus unites with the
egg to form the diploid zygote, from which the embryo develops, and
the other unites with two polar nuclei to form the triploid,
primary endosperm nucleus (nutrition).
Slide 16
Flower anatomy
Slide 17
Angiosperms
Slide 18
Seeds monocots & dicots DICOT MONOCOT
Slide 19
Germination 1. Imbibation taking in H2O 2. ABA decreases (plant
soluble hormone that causes dormancy) 3. Embryo responds and
releases gibberellin (stimulates release of amylase) 4. Amylase
breaks down starch for nutrition which allows for growth 5. Root
extends downward while shoot extends upward
Slide 20
Factors affecting germination HOW? Water Oxygen Temperature
Light