Download Phylum Bryophyta or Mosses

Plant Diversity and Evolution
Part 1
Outline
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Introduction
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Introduction to the Bryophytes
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Phylum Hepaticophyta – Liverworts
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Phylum Anthocerophyta – Hornworts
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Phylum Bryophyta – Mosses
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Human and Ecological Relevance of Bryophytes
Introduction
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All plants and green algae share the following
characteristics:
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Pigments: Chlorophylls a and b, carotenoids
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Storage of Energy: Starch as food reserve
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Cell Walls: Cellulose in cell walls
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Phragmoplast and cell plate during cell division
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These shared features suggest a common ancestor.
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Land plants first appeared 400 million years ago.
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Ancestor progressed from aquatic to land habitat even
earlier.
By the time plants became established on land, they had
several features to prevent them from drying:
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Plant surfaces developed fatty cuticle to retard water
loss.
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Gametangia (gamete-producing structures) and
sporangia (spore-producing structures) became
multicellular and surrounded by jacket of sterile cells.
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Zygotes developed into multicellular embryos within
parental tissues that originally surrounded egg.
Bryophytes
Maples in Olympic National Park's Hoh Rain Forest. Maples in Olympic National Park's Hoh Rain Forest.
Characteristics of Bryophytes
About 23,000 species of bryophytes. Include mosses,
liverworts, and hornworts
Occupy wide range of habitats:
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Damp banks, trees, logs
Bare rocks in scorching sun
Frozen alpine slopes
In elevations from sea level up to 5,500 meters or
more
Bryophytes often have mycorrhizal fungi
associated with their rhizoids.
Peat mosses are ecologically important in bogs.
Luminous mosses are found in caves and in other
dark, damp places.
There are several
economical and
ethnobotanical uses.
Species of Sphagnum
have been used for
external medical
treatment as wound
dressings, a use that has
been documented to have
taken place since the ice
ages and continued on a
large scale well into the
20th century during both
world wars.
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Decaying Sphagnum is also the major component of peat, which is
"mined" for use as a fuel, as a horticultural soil additive, and in
smoking malt in the production of Scotch whisky.
Peat gatherers at Westhay, Somerset Levels in 1905. Alexander Eric Hasse (1875-1935) - A.E.Hasse,
Baildon, Yorkshire. Orig. 6x6 glass plate diapositive
New Forest Peat Bog by Lucy Morris
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Decaying Sphagnum is also the major component of peat, which is
"mined" for use as a fuel, as a horticultural soil additive, and in smoking malt
in the production of Scotch whisky.
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Arctic people used mosses for bedding. North American tribal people used
mosses for basketry, bedding, wound dressing, diapers, and menstrual fluid
absorption. Circumpolar and alpine people used mosses as insulation in
boots and mittens. Tribes of northeastern United States and southeastern
Canada used moss to fill chinks in wooden longhouses*.
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Tribes of the Pacific Northwest in the US and Canada used mosses to clean
salmon prior to drying, and packed wet moss into pit ovens for steaming
camas bulbs*. Food storage baskets and boiling baskets were also packed
with mosses**.
*These bulbs are also known as the flowering bulb Stilla. This is also a starchy edible bulb.
**All information above from Kimmerer, Robin Wall (2003). Gathering Moss
Botanical characteristics of Bryophytes
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None have true xylem or phloem: Many have hydroids for
water conduction, however most water absorbed directly
through surface. A few have leptoids for food-conduction.
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To reproduce sexually, must have external water.
Bryophytes exhibit alteration of generations
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In mosses, leafy plant is major part of gametophyte
generation. Gametophyte produces gametes.
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Sporophyte generation grows from gametophyte.
Sporophyte produces spores.
Bryophyte Evolution.
There are three distinct bryophyte phyla but none appear
closely related to other living plants. Bryophyte lines may
have arisen independently from ancestral green algae.
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The three phyla are:
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Hepaticophyta or liverworts
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Phylum Anthocerophyta – Hornworts
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Phylum Bryophyta – Mosses
Phylum Hepaticophyta or Liverworts
There are about 9000 species of liverworts. Some grow as a
flattened leafless thallus, but most species are leafy with a form
very much like a flattened moss.
Liverworts are, from 2–20 mm wide and 10 cm long.
The name comes from their leaflets being similar to the shape of a liver
with deep lobes or segmented leaves and a lack of clearly differentiated
stem and leaves.
Leafy species can be distinguished from mosses because they have
unicellular rhizoids.
Archegonia and antheridia produced in cuplike structures composed of
modified leaves, in axils of leaves or on separate branches.
Phylum Anthocerophyta – Hornworts
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The common name of hornworts refers to the elongated
horn-like sporophyte and the flattened, green plant body of
a hornwort is the gametophyte.
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There are about 100 species worldwide
Phylum Bryophyta or Mosses
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About 15,000 species of mosses currently known.
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Mosses are divided into three classes:
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Peat mosses
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True mosses
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Rock mosses
Phylum Bryophyta – Mosses
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Sexual reproduction:
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Archegonia release substances that attract sperm.
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Sperm swim down neck of archegonium.
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Zygote grows into spindle-shaped embryo.
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Top of archegonium splits off and forms cap on top of sporophyte = calyptra.
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Mature sporophyte consists of capsule, seta and foot.
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Meiosis produces spores inside capsule.
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Peristome, composed of one or two rows of teeth, under operculum at tip of capsule.
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Peristome opens or closes in response to humidity.
Spores develop into filamentous protonema that produces buds that develop into leafy
gametophytes.
Human and Ecological
Relevance of Bryophytes
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Pioneer species on bare rock after volcanic eruptions or other geological upheavals = succession
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Accumulate mineral and organic matter that is utilized by other organisms
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Retain moisture, and reduce flooding and erosion
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Indicators of surface water
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Packing material
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Peat mosses most important bryophyte to humans.
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Soil conditioner due to high absorptive capacity
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Poultice material due to antiseptic properties and absorbency
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Fuel
Review
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Introduction
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Introduction to the Bryophytes
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Phylum Hepaticophyta – Liverworts
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Phylum Anthocerophyta – Hornworts
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Phylum Bryophyta – Mosses
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Human and Ecological Relevance of Bryophytes
The Seedless Vascular Plants
Ferns and their relatives
Outline
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Introduction
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Phylum Psilotophyta – The Whisk Ferns
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Phylum Lycophyta – The Ground Pines, Spike
Mosses and Quillworts
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Phylum Equisetophyta – The Horsetails and
Scouring Rushes
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Phylum Polypodiophyta – The Ferns
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Fossils
Introduction
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During early stages of vascular plant evolution:
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Internal conducting tissue developed.
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True leaves appeared.
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Roots that function in absorption and anchorage developed.
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Gametophytes became progressively smaller.
Four phyla of seedless vascular plants: Psilotophyta,
Lycophyta, Equisetophyta, Polypodiophyta
Phylum Psilotophyta.
The Whisk Ferns
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Resemble small, green whisk
brooms.
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Sporophytes (main body) have
neither true leaves, nor roots.
It rhyzomes instead and
“enations” (superficially
leaflike, veinless,
photosynthetic flaps of tissue.
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Stems and rhizomes fork
evenly (dichotomously).
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Examples is Psilotum.
Phylum Lycophyta.
Club mosses
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The Ground Pines, Spike Mosses, and
Quillworts
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Collectively called club mosses.
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There are only four living genera,
many more genera became extinct
about 270 million years ago.
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Have true roots and stems
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Plants covered with microphylls
(leaves with single vein). Examples
are Lycopodium and Sellaginella.
Although today’s species of club mosses an quillworts are
very small, their ancient relatives were large, tree-like, up to
30 meters. They dominated forests and swamps during the
carboniferous period (325 million years ago). Example is
Lepidodendron.
Equisetophyta
Have whorled, scalelike
microphylls that lack
chlorophyll. They are also
known a scouring rushes
because the ribbed stems
containing silica. Example is
Equisetum.
Polypodiophyta
Sporophytes have megaphylls
(leaves with more than one
vein). The leaves are much
divided and known as fronds.
Phylum Equisetophyta or Horsetails and Scouring
Rushes
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They are also known a scouring rushes because the ribbed
stems containing silica.
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Usually less than 1.3 meters tall. The stems are jointed and
ribbed. The stems can be branched or unbranched. If
branched, then branches in whorls.
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Have whorled, scale-like microphylls
that lack chlorophyll.
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Equisetum laevigatum and E.
temateia rootstocks are eaten by the
Makah, Hoh and the Quileute tribes
and also used during special puberty
ceremonies. These tribes also use
species of Equisetum to feed horses
and some other species of are known
to provide food for grizzly bears.
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Equisetum arvense has medicinal
properties. It is used as a diuretic and
to treat bladder and kidney infections.
Applied directly to a wound, it can
help stop bleeding.
The Equisetales flourished in Carboniferous, 300 million years
ago. Calamites is a genus of extinct arborescent horsetails
closely related to modern horsetails (genus Equisetum).
Unlike modern herbaceous Equisetum, these plants were
medium-sized trees, growing to heights of more than 30
meters (100 feet).