11.2 Mosses and Ferns
11.2 Mosses & Ferns need moisture
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From original water-based plant forms, plants
eventually adapted to life on land
Plant life appeared on Earth about 475 million
years ago
Plants were first to move from water
environment to land.
Resembled green algae
They are autotrophs & producers
11.2 First Plants
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Plants first appeared in water (tiny, floating
organisms that could photosynthesize)
As ponds/rivers got crowded or dried up,
some were pushed to the side.
Those that could adapt and survive became
ancestors to the first land plants.
Advantages: land had plenty of CO2 and
direct sunlight
11.2 Mosses and Ferns
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Mosses are simpler in structure than ferns
Related plants = liverworts and hornworts are
related to mosses descended from the first
plants.
Ferns and their relatives appeared later.
11.2 Mosses are non-vascular
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Each moss cell is surrounded by a thick cell wall that
supports it.
Their cells have special storage areas for water and
nutrients and water plays an important part in the
reproductive cycle.
They do not grow tall or large, but they have
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Simple structures that function like roots, stems, and leaves
They are non-vascular (do not have vascular tissues) so
water and nutrients simply move throughout the plants’
bodies cell by cell (diffusion).
11.2 Mosses reproduce w/spores
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Mosses, ferns and fungi all reproduce (both asexually &
sexually) with spores (which are an adaptation).
Life Cycle: Generation 1
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1st Half: Moss grows & maintains itself
Produces male/female structures need to reproduce
2nd Half: If there’s enough water, plant produces spores (both
sperm and egg cells)
Water must be present for sperm & egg to fertilize
Offspring (Generation 2) grow into a stalk with capsule on
its end
11.2 Ferns
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Ferns, horsetails, and club mosses are related vascular
plants
Ferns = first plants with a vascular tissue system (vts)
Because they can transport water (etc) using vts and
because the vts also provide support, they can grow
larger.
VTS allows for branching of root systems (which anchor
the plant) and leaf systems (more sugar/energy, etc).
11.2 Fern reproduction
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Leaves of a fern are called fronds
Spore clusters are on the back of the frond.
Can reproduce sexually & asexually (branching,
cuttings)
Life Cycle: Generation 1
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Spores grow in structures near the ground (thumbnail sized)
which contain the sperm and egg producing parts of fern.
Water is needed to stimulate & assist w/ fertilization.
Gen.2 = Fern w/fronds grows from the fertilized egg.
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As fronds grow, egg bearing part dies away. Fronds produce
clusters of cells within which meiosis takes place and
male/female spores are made.
Spores spread through air to grow into Gen.1
Fern
With
Spores