Diversity of Plants and Fungi
BIO 101
Life Science
Dr. D. L. Daley
Evolutionary Tree
of Plants
Overview of Plants
w
Non-vascular plants - (Bryophytes)
•
18,600
species
•
Liverworts,
hornworts & mosses
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Vascular plants (Tracheophytes) - internal tissues to
conduct water and solutes through the roots, stems and leaves
•
276,400
species
•
Seedless vascular plants - ferns and horsetails
•
Gymnosperms - Nonflowering seed plants - cycads, gingkos, conifers and gnetophytes
•
Angiosperms - flowering seed plants
Bryophytes
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Mosses, liverworts and hornworts
w
Non-vascular plants
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No taller than 8 inches
w
They have leaflike, stemlike
and rootlike parts but no xylem and phloem
w
Have rhizoids for underground absorption
Bryophytes
w Have a cuticle to prevent
water loss
w Have cellular jacket around
parts that produce eggs and sperm - holds in moisture
w Archegonia - structures where the eggs
develop
w Antheridia - structures where sperm
form
w In some bryophytes the
archegonia and antheria are located on the same plant
- in other there are individual male and female plants
w The sperm must swim to the
egg through a film of water - in dry climates the reproduction must be times to
coincide with the rains
Bryophytes
Hornworts
Mosses
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Most common brytophyte
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Grow in clusters
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Most diverse and abundant group of bryophytes
w Many mosses are able to
survive the loss of much of the water in their bodies - they dehydrate and
become dormant during dry periods
Peat Mosses
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350 kinds
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Commonly accumulates in bogs - many layers compressed
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Peat bogs in cold and temperate regions of the world represents and
area equal to 1/2 the united States
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The peat moss secretes acids that inhibit bacterial and fungal
breakdown
Why have vascular
plants done so well?
1. Developed root
systems - collect water and minerals from large area
2. Shoot systems -
stems and leaves to absorb energy from sun and CO2 from the air
3. Cellular
pipelines developed
Xylem - carries
water & dissolved ions
Phloem - carries
dissolved sugars and other photosynthetic products
4. Cuticle - waxy
coat that helps the plants conserve water
Stomata - openings
- control water loss and CO2 absorption
How Xylem Works
How Phloem works
Seedless Vascular
Plants
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Whisk Ferns - Psilophyta
•
No
roots only rhizomes - short mostly horizontal absorptive stems
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Lycophytes - most familiar - club mosses
Seedless Vascular
Plants
w Horsetails - silica
reinforced stems
w Ferns - largest most diverse
group
•
Rust colored patches below the fronds of ferns - sorus
- spore producing
Some Seedless
Vascular Plants
Ferns
Seed-Bearing
Plants
w Dominate the land - aided by two
adaptations
•
Pollen and seeds
w Pollen grains - tiny structures that
carry the sperm producing cells
•
Pollen grains are dispersed by wind or animal pollinators such as bees
•
Pollen grains mean that these plants do not need water to carry the
sperm to the egg such as in bryophytes
w Seeds - embryonic plant, a food
supply and a protective outer coat
•
The seed coat keeps the embryo in a state of suspended animation or
dormancy until proper conditions occur
Gymnosperms
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Naked-seed - not enclosed in reproductive structure as in flowering
plants
w Conifers - scalelike
or needlelike leaves - seeds exposed on cone scales
•
Most
abundant - pines
•
Tallest
- redwoods
•
Oldest
- bristlecone pines
s
4725 years old - sprouted when the Egyptians built the Great Sphinx
• Also includes firs , junipers, spruces and yews
Gymnosperms
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Cycads
•
Separate
pollen bearing and seedbearing cones
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Leaves
resemble palm trees
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Most
subtropical or tropical
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Ginkos
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Common
in dinosaur times
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Only
one survivor - maidenhair tree
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Gnetophytes
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Woody
plants
•
Not
very common
Gymnosperms
Angiosperms
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Flowering, seed-bearing plants
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Flowers are specialized reproductive structures
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Angeion - means vessel - refers to the female reproductive
parts at the center of the flower
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Pollinators are insects, birds, bats and other animals - help transfer
pollen to the female reproductive parts
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260,000 species
Classes of
Angiosperms
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Monocots - one seed leaf
•
Orchids,
palms, lilies and grasses
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Eudicots - two seed leafs
•
Most
herbaceous - such as cabbages and daisies
•
Also
flowering shrubs, trees (like oak and apple), water lilies and cacti
Monocots
Eudicots
Fungi
•
A
Fungus Is not a Plant
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Heterotrophs - require organic compounds
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They have filamentous bodies - slender filaments called hypae
•
Form
long chains of
cells - connected by septa
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Mass
of connected hypae - mycelium
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Cells walls made of chitin - polysaccharide
Major Groups of
Fungi
w Zygomycetes
•
e.g. Bread mold
w Sac Fungi (Ascomycetes)
•
Yeasts, common molds & morels and truffles
Major Groups of
Fungi
w Club Fungi (Basidiomycetes)
•
Mushrooms, puffballs, toadstools and shelf fungi
Life Cycle of a Basidiomycetes
w Mushroom (basidocarp)
- short lived reproductive bodies
•
The above ground part
w Mycelium - lives below ground
•
Extensive mesh of branched filaments
•
Also called a primary mycelium
Life Cycle of a Basidiomycetes
w Mushroom or basidocarp
- stalk and a cap
•
Gills line inner surface of cap
w Gills
•
Club-shaped spore bearing structures - basidium
•
Spores - called basidospores
w Basidospores land suitable site -
mycelium forms
Life Cycle of a Basidiomycetes
w Filament (hypha) of one strain meets another
•
Cytoplasm fuses - not nuclei
•
Secondary mycelium forms
s Each cell has two nuclei - one from each
strain
• Extensive mycelium forms
Life Cycle of a Basidiomycetes
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Favorable conditions - get new mushroom
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Each new mushroom - entirely of secondary mycelium
•
Mushroom
- composed of densely packed secondary mycelium
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Two nuclei may fuse - get short-lived zygote
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The zygote undergoes reduction division
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Haploid spores (basidospores) form on small stalks - air
currents disperse them
Life Cycle of a
Typical Basidiomycetes
Fungal Diversity
w Black bread mold - Rhizopus stolonifer
w Common morel - sac fungi
w Penicillium - sac fungi
•
Roqueford cheese & antibiotics
w Candidida albicans
- yeast infection in humans
w Athletes foot
A Fungus that is a
Predator
Lichens
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Symbionts - two species live together
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Mutualism (both benefit)
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Single vegetative body
•
Fungal part (mycobiont) & photosynthetic
species (photobiont)
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13,500 species
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Most are sac fungi & green algae
or cyanobacteria
Structure of
Lichen
Fungus largest
component
Outer cortex of mycobiont
Below top
cortex
is the photobiont
Dispersal fragment
can
occur from top surface
Mycobiont & photobiont