Transcript Chapter 29 and 30 ppt

Colonization of Land
Kingdom Plantae
Four Main Groups of Land Plants
Liverworts
Hornworts
Moss
Four Main Groups of Land Plants
1) Bryophytes: non-vascular plants
•
Non vascular (no tissues of cells joined into
tubes to transport water or nutrients)
Four Main Groups of Land Plants
Lycophyte - Club “Moss”
Horsetail
Whisk Fern
Fern
Four Main Groups of Land Plants
1) Bryophytes: non-vascular plants
•
Non vascular (no tissues of cells joined into
tubes to transport water or nutrients)
2) Pteridophytes: seedless plants
Four Main Groups of Land Plants
conifers
Four Main Groups of Land Plants
1) Bryophytes: non-vascular plants
•
Non vascular (no tissues of cells joined into
tubes to transport water or nutrients)
2) Pteridophytes: seedless plants
3) Gymnosperms: plants with naked
seeds (seeds protected in cones)
Four Main Groups of Land Plants
Flowering plants
Four Main Groups of Land Plants
1) Bryophytes: non-vascular plants
•
Non vascular (no tissues of cells joined into
tubes to transport water or nutrients)
2) Pteridophytes: seedless plants
3) Gymnosperms: plants with naked
seeds
4) Angiosperms: flowering plants with
seeds protected in ovaries (fruit)
Vascular
Plants
Where did plants evolve from?
From Charophycean Algae
Evidence? Homologies in…
1) Rose-shaped proteins
that make cellulose in
cell walls
2) Peroxisome organelle
most closely associated
with chloroplasts
3) Sperm Structure
4) Cell plate formation
during division
Plant Adaptations
1. Apical Meristems:
Localized areas of cell
division at tips of
shoots and roots
Adaptive significance:
Plant tissues
differentiate and
serve different
functions
Plant Adaptations
2. Multicellular embryos
remain within tissues
of female parents
Adaptive significance:
Placental transfer of
nutrients, AA, sugars
from parents to
embryo
Plant Adaptations
3. Alternation of
Generation Life Cycle
Gametophyte
generation is
dominant in
bryophytes
Sporophyte generation
is dominant in
vascular plants
Plant Adaptations
4. Sporangia: organs
found in sporophytes
(2N) that make
spores (N)
Adaptive significance:
Spores are durable and
tough; resistant to
harsh environments
Plant Adaptations
5. Gametangia: organs
found on
gametophytes (N)
which make gametes
(N)
Archegonia: Female
gametangia
Antheridia: Male
Gametangia
egg
sperm
Plant Adaptations
6. Cuticle: Waxy
covering on leaves
Stomata: Pores under
leaves
Adaptive Significance:
Prevents water loss and
microbial attack while
also allowing for gas
exchange
Plant Adaptations
7. Vascular Transport
System
Xylem: Specialized cells
that transport water
Phloem: Specialized cells
that transport
carbohydrates and other
nutrients
Adaptive Significance:
Ability to grow higher away
from the ground
Plant Adaptations
8. Secondary Compounds - Flavonoids,
Alkaloids, Tannins with bitter tastes, strong
odors, toxic effects
Adaptive Significance
Defense against UV rays, microbes, herbivores
Plant Adaptations
9. Deciduousness
Shedding of leaves
Adaptive Significance:
Minimizes water loss
and energy waste
during dormant
seasons
Bryophytes
Group 1 - nonvascular
Ex. Liverworts, hornworts, mosses
Gametophyte (N) generation is
dominant (larger) in Bryophytes
Gametophyte (N) generation is
dominant (larger) in Bryophytes
Gametophyte (N) generation is
dominant (larger) in Bryophytes
Protonema:
Multicellular (N)
with large SA to
absorb water
and minerals
“rhizoids” = fake
roots used for
anchoring, not
water absorption
Sprophyte (2N) small and
insignificant; attached to
gametophytes
Pteridophytes
Group 2 – seedless, vascular
Ex. Lycophytes(club “moss”), pterophytes
(ferns), sphenophytes (horsetails)
Sporophyte (2N) generation is
dominant (larger) in Pteridophytes
Sporophyte
(2N) “leaves
of ferns”
Sporangia = called “sori” in ferns; produces
(N) spores by meiosis
Sporophyte (2N) generation is
dominant (larger) in Pteridophytes
Significantly small and less
complex (N) gametophyte with
large sporophyte growing out of it
Lycophytes or Club “moss”
Club shaped “strobili” =
sporangia
These can typically be
“epiphytes” or grow
on other plants
Sphenophytes or “horsetails”
Strobili
Hollow ribbed stems
joined at “nodes” with
small scale-like
leaves
What did you notice about the size
of the gametophytes of the first two
plant groups?
• The gametophyte of the bryophytes are
larger and more complex
_______________________
while that of
smaller
the pteriodophytes are _____________
In plants that produce seeds, the
reduction of gametophytes
continues
Adaptive Advantage:
1. Gametophyte is protected
from environment
2. Embryo is protected
3. Gametophyte can get
nutrients from sporophyte
In seed plants, the sporophyte has
2 kinds of sporangia
Female Sporangia (2N)
= Megasporangia
(Found inside of an
ovule)
megaspore(N)
Megasporangia
produces haploid
megaspores through
meiosis
Integument: protective
layer that later
becomes the seed coat
Ovule
In seed plants, the sporophyte has
2 kinds of sporangia
Male Sporangia (2N)
= microsporangia
(found inside of the
anther/pollen sac)
Microsporangia
produces haploid
microspores through
meiosis
Pollen Sac =
Microsporangia
Mega and Microspores  female
or male gametophytes
Gametophytes created
from the mega and
microspores by
mitosis
___________
Female gametophyte is
contained within the
ovule
Male gametophyte =
pollen
gametes
Gametophytes create _________
Male gametophytes
create sperm
(contained within the
pollen grain)
Female gametophytes
create egg (contained
within the ovule)
Pollination
Definition: the transfer of pollen to ovule
Adaptive Advantage of Pollen:
eliminated the need for water to transfer
sperm to egg
Pollination
When pollen lands on
an ovule, a pollen
tube forms and sperm
move through the
tube to fertilize the
egg inside the ovule
Diploid
Zygote
within ovule
Pollen tube
Micropile = opening
through integument
that allows pollen to
access the egg
seed
Pollen grain
Gymnosperms
Group 3 – naked seeds, vascular
Ex. Conifers, Pines, Cedar, Redwoods
Gymnosperms
• They have “naked”
seeds
• Lack ovaries (fruit) in
which ovules (seeds)
develop
• Ovules develop on
specialized leaves
called sporophyll
Sporangia by a different name…
Megasporangia of
gymnosperms are
contained within
female ovulate cones
• Microsporangia of
gymnosperms are
contained within male
pollen cones
Life Cycle of a Gymnosperm
Life Cycle of a Gymnosperm
Life Cycle of a Gymnosperm
Angiosperm
Group 4 – flowering plants, vascular
Seeds are contained in protected ovaries (fruit)
Parts of a Flower
Stigma
Stamen
(male)
Anther
Filament
Style
Ovary
petals
ovule
sepal
Carpel/
Pistil
(female)
Sperm Formation
Anther contains the
microsporangia
Microsporangia (2N) creates
4 haploid microspores by
meiosis
Each microspore will
undergo mitosis to
make a generative cell
and a tube cell
Generative cell goes
through mitosis to create
2 sperm
Pollen = male
gametophyte
Gametes (2
sperm) formed
by
gametophyte
Egg Formation
Megasporangia
divides by meiosis
to create 4 haploid
megaspores
3 megaspores
die
Female gametophyte
3 mitotic divisions
3 Antipodal cells
2 Polar nuclei
2 synergids
egg
Double Fertilization of ovule
Pollen containing
2 sperm and 1
tube cell
1. Tube cell
creates a
pollen tube
down the style
until it reaches
the micropile
2. The 2 sperm
follow the path
of the tube to
the egg
5. Ovule is now a
seed; the ovary
develops into a fruit
3. One sperm fertilizes the
egg, creating a diploid
zygote
4. 2nd sperm fuses with the 2 polar
nuclei, creating a 3N nucleus. This
divides and forms the “endosperm” =
nourishment and food for the zygote
Fruit assists in seed dispersal
and protects the seed with the
developing embryo