Plant Life Cycle

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Station 1
Plant Life Cycle

• All plants have a life cycle with alternation of
  generations
• the haploid gametophyte phase alternates with the
  diploid sporophyte phase.
• Gametophyte (N) - gamete producing plant
• Sporophyte (2N) Spore producing plant

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Station 1
ALTERNATION OF GENERATIONS
A multicellular diploid sporophyte plant (2n)
produces haploid spores (1n) through
meiosis. Spores are either male or female. Spores
go through mitosis to form a multicellular male
or female haploid stage called a gametophyte (or
gamete producing organism). The gametophyte plant
is either male or female as well hence a male
gametophyte or a female gametophyte. The male
gametophyte produces male gametes (sex cells) and
the female gametophyte produces female gametes by
going through mitosis. Fertilization results in a
diploid zygote which develops into the next
sporophyte generation.
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Station 2
What plants need to survive

• Sunlight
• Water and Minerals
• Gas Exchange
• (CO2 for photosynthesis and O2 for cellular
  respiration)
• Movement of Water and Nutrients

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Station 2
Evolution of plants

• The first plants evolved from an organism much
  like the multicellular green algae living today.

Today's Plants (from simplest to most advanced)
1. Nonvascular Plants 2. Vascular Plants without
Seeds 3. Vascular Plants with Seeds 4. Vascular
Plants with Seeds and Flowers
Four divisions based on water-conducting tissues,
seeds, and flowers.
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Station 2
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Station 3
Nonvascular PlantsMosses, Liverworts, and
Hornworts

• Lack vascular tissue (no true roots, stems or
  leaves)
• Mosses are pioneer plants
• Key to primary succession
• Seedless

Mosses Liverworts Hornworts
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Station 4
Vascular Plants w/o seeds Whisk Ferns, Club
Mosses, Horsetails, Ferns
Club Mosses Horsetails Ferns

• Vascular - Can grow taller and transport
  necessities
• Have vascular tissue but no seeds
• Cell walls contain lignin (tough material for
  support)
• Seedless - Have sperm that swim to egg cells (in
  dew)

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Station 4
Vascular Plant Parts

• Roots
• Leaves
• Stems

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Station 4
Vascular Tissue

• Tracheids- hollow cells with thick cell walls
  that resist pressure. Connected end to end to
  move water
• Xylem Water and minerals from roots to other
  parts of the plants (up)
• Phloem Sugars and organic material from leaves
  to other parts of the plants (down)

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Station 5
Vascular Bundle
Phloem
Xylem
Cambium
Cortex
Epidermis
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Vascular Plants w/ Seeds
Station 5

• Have vascular tissue
• Reproduce with seeds
• Seeds contain plant embryo and 1-2 cotyledons
  (embryonic leaves)
• Seeds help survive poor conditions
• Do not need water for fertilization

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Station 5
Groups of Seed Plants

• Gymnosperm naked seeds
• Angiosperm Flowering plants

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Station 5
Seed Dispersal

• Dispersal by Animals-
• Seeds dispersed by animals are typically
  contained in fleshy, nutritious fruits.
• Tough coatings protect them from digestive
  chemicals, enabling them to pass through an
  animals digestive system unharmed.
• Dispersal by Wind and Water 
• Seeds dispersed by wind or water are typically
  lightweight, allowing them to be carried in the
  air or to float on the surface of the water.

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Station 6
Vascular Plants w/ Seeds Gymnosperms

• Cycads, Ginkgoes, Conifers, Gnetophytes
• Seeds in cones
• Usually evergreens
• Leaves needle-like or scale-like

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Station 6
4 Types of Gymnosperms

• Phylum Ginkgophyta
• Gingko
• Leaves fan-shaped
• Only one species
• Ancient group

• Phylum Coniferophyta
• Cone Bearers
• Pine Trees

• Phylum Cycadophyta
• Cycads
• palm-like ancient group (not palms)

• Phylum Gnetophyta
• Assumed to be the closest related to flowering
  plants
• Ex Ephedra

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Station 6
ALTERNATION OF GENERATIONS
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Station 7
Today's most successful plants are Angiosperms
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Station 7
Angiosperm (Phylum Anthophyta)

• Mature seeds are enclosed in fruits
• Most species of plants
• Flowers are reproductive structures
• Male stamen
• Female carpel or pistil

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Station 7
ALTERNATION OF GENERATIONS
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Station 8
Identify each of the following plants as either
monocots or dicots
B
C
D
E
A
I
F
G
H
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Station 8
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Station 8
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Station 8
Cotyledons Structure in the embryo of a seed
plant that may form a leaf after germination
and is commonly known as a seed leaf. It is not a
true foliage leaf. It fills most of the seed's
volume. In a monocot, there is only one. In a
dicot, there are two cotyledons visible...seed
opens into 2 halves. Epicotyl The first shoot
that emerges. The epicotyl in this picture has
macroscopic leaves visible. Hypocotyl The
hypocotyl is the primary organ of extension of
the young plant and develops into the stem. It
is the region of the stem BELOW the
Cotyledons. Radicle The primary root of a plant,
developed in a seedling the embryonic root of a
seedling
Radicle
CS
Cotyledon scar
H
Hypocotyl
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Station 9
Plant Lifespan

• Annual - flowering plant that completes a life
  cycle within one growing season
• Biennial - flowering plant that completes its
  life cycle in two years
• Perennial - flowering plant that lives for more
  than two years

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Station 9
Pollination, fertilization, germination, and
dormancy

• Pollination To transfer pollen from an anther
  to the stigma of (a flower)
• Fertilization The union of male and female
  gametes to form a zygote
• Germination - early growth stage of a plant
  embryo
• Dormancy - period of time during which a plant
  embryo is alive but not growing

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Station 9
Pollinators (http//pollinators.nbii.gov/portal/s
erver.pt) Imagine living in a world without bees
or other pollinators! It would be a world without
flowers, fruit, even a cup of coffee. A world,
even, without chocolate! Thanks to the wonderful
work of bees, butterflies, birds, and
other animal pollinators, the world's flowering
plants are able to reproduce and bear fruit,
providing many of the foods we eat, the plant
materials we and other organisms use, and the
beauty we see around us. Yet today, there is
evidence indicating alarming pollinator
population declines worldwide. Domesticated
honeybees are not the only pollinators in trouble
these days. Many species of butterflies, moths,
birds, bats and other pollinators are also in
retreat, threatening not only the production of
commercial crops but also a wide range of
flowering plants, including rare and endangered
species. "Action must be taken to reverse these
trends," says Stephen Buchmann, an entomologist
at the U.S. Department of Agriculture's Carl
Hayden Bee Research Center in Tucson, Arizona.
According to Buchmann, only a few of these
pollinators (mainly Hawaiian bird species) are
protected by the Federal Endangered Species Act.
"This is simply because the world is focused on
the charismatic megafauna--the lions and tigers
and bears," he says. "The little things that run
the world, including bees, butterflies, bats and
hummingbirds, go unnoticed and unprotected until
it is sometimes too late."