I. Delineation of groups by phylogeny · "Bryophytes" Red Algae Gymnosperms & Angionsperms "Ferns &...
Transcript of I. Delineation of groups by phylogeny · "Bryophytes" Red Algae Gymnosperms & Angionsperms "Ferns &...
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L13: Bryophytes
BIOL 153/LBlack Hills State Univ.Ramseys
I. Delineation of groups by phylogenyA. Definitions
1. Monophyletic group
all descendents of one common ancestor
2. Paraphyletic group
many but not all descendents of one common ancestor
3. Polyphyletic group
descendants of two (or more) ancestors
I. Delineation of groups by phylogenyB. Illustrations using trees
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Fig. 12-4Raven p. 238
Fig. 12-4Raven p. 238
I. Delineation of groups by phylogeny
C. Treatment of non-monophyletic groups
1. Functional groupings
paraphyletic or polyphyletic groups of organisms with similar ecology
Examples:
• "Algae"
• "Moss"
• Phytoplankton
2. Paraphyletic groupings (almost monophyletic)
otherwise monophyletic group in which one lineage is elevated
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Example: II. Origin of Land Plants
A. Green Plants
Photosynthetic Organismson the Tree of Life
Primary Origin of Chloroplast
Primary Origin of ChloroplastPlant Kingdom(Green Plants)
II. Origin of Land Plants
B. Land Plants
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1. "Bryophytes"
mosses, liverworts, hornworts
2. "Ferns & Fern Allies"
ferns, lycopods, horsetails, spike moss
3. Gymnosperms
conifers, cycads, ginkgo, gnetophytes
4. Angiosperms
flowering plants (dicots, monocots)
II. Origin of Land Plants
C. Paraphyly in Green Plants "Green Algae"
"Bryophytes"
"Ferns & Allies"
Red Algae
Gymnosperms & Angionsperms
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"Green Algae"
"Bryophytes"
Red Algae
Gymnosperms & Angionsperms
"Ferns & Allies"
"Green Algae"
"Bryophytes"
Red Algae
Gymnosperms & Angionsperms
"Ferns & Allies"
"Ferns & Allies"
"Green Algae"
"Bryophytes"
Red Algae
Gymnosperms & Angionsperms
"Green Algae"
"Bryophytes"
"Ferns & Fern Allies"
Red Algae
Gymnosperms & Angionsperms
Plant Kingdom
aka
Green Plants
Two-kingdom system
Three-kingdom system
Five-kingdom system
Modern system
"Green Algae"
"Bryophytes"
"Ferns & Fern Allies"
Red Algae
Gymnosperms & Angionsperms
LandPlants
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III. Life on Land
A. Challenges
1. Dessication
loss of moisture to environment
2. Gamete movement
aquatic organisms have swimming gametes
3. Structural support
tissues of aquatic organisms bouyantand flexible
4. Transport
large dessicant-resistant body has transport + exchange challenges!
5. Atmospheric oxygen
O2 bad for plants (inhibits photosynthesis)
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III. Life on land
B. Adaptations in Green Plants
1. Embryo
multicellular embryo is protected, given head-start
2. Stomata
small pores for gas exchange
3. Vascular tissues
xylem + phloem for water + sugar
4. Wood
structural tissue (stems, roots)
5. Pollen
small protected male gametophyte (transports sperm)
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6. Seeds
protective case w/ food for embryo
"Green Algae"
"Bryophytes"
"Ferns & Fern Allies"
Red Algae
Gymnosperms & Angionspermsorigin of terrestrial
adaptations in Green Plants
"Green Algae"
"Bryophytes"
"Ferns & Fern Allies"
Red Algae
Gymnosperms & Angionsperms
Stomata
Embryo
"Green Algae"
"Bryophytes"
"Ferns & Fern Allies"
Red Algae
Gymnosperms & AngionspermsVascular tissues
"Green Algae"
"Bryophytes"
"Ferns & Fern Allies"
Red Algae
Gymnosperms & Angionsperms
Wood Pollen Seeds
IV. Introduction to "Bryophytes"
A. Types
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1. Mosses
small, mat-forming; elongate gametophyte w/ simple leaves; threadlike sporophyte
widespread and diverse
2. Liverwort
flattened thallus, leafless; stalk-like sporophyte w/ umbrella head
widespread and diverse
3. Hornworts
ribbonlike thallus, leafless; horn-shaped sporophyte
mostly tropical, not many species
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IV. Introduction to "Bryophytes"
B. Evolutionary relationshipsHornwortsLiverworts
Mosses
IV. Introduction to "Bryophytes"
C. Dominance of gametophyte stage
largest, most persistent stage is gametophyte
IV. Introduction to "Bryophytes"
D. Life in terrestrial environment
1. Adaptations present
embryo + stomata
Fig. 16-8Raven p. 371
sporophyte developing fromembryo (liverwort)
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Fig. 16-25Raven p. 384
Stomata(moss)
1. Adaptations present
2. Adaptations absent
embryo + stomata
vascular tissue + roots wood, pollen, seedsflowers + fruits
V. Life cycles of "Bryophytes"
A. Key concepts
1. Spore vs. gamete
spores are direct product of meiosis, do mitosisgametes produced later, undergo fertilization
2. Sporophyte vs. gametophyte
sporophyte is diploid, produces spores by meiosisgametophyte is haploid, produces gametes by mitosis
3. Archegonia and antheridia
multicellular structures on gametophyte, produce gametes
4. Other structures
capsule, seta, gemma cup, etc.
V. Life cycles of "Bryophytes"
B. Moss example
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IV. Ecology of "Bryophytes"
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A. Asexual reproduction Most bryophyte reproduction is asexual via:
• Fragmentation
• Clonal growth
• Specialized structures
Gemma cups (asexual reproduction)
Fig. 16-13a
B. Habitats
1. In general...
• Wet environments
• Tolerant of dry periods
• Soil not required
Microenvironment:
small area distinct from surrounding landscape
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• In wet areas: mosses common, liverworts occasional
• North Hills cooler and wetter than South Hills
• Gorges/gullies really wet; example: Spearfish Canyon
2. In the Black Hills... C. Sphagnum moss (aka "peat moss")
1. Characteristics of Sphagnum
• Absorbent: 1 (part sphagnum) : 16+ (parts water)
• Acidifying: preserves & slows decomposition
• Anaerobic: slows decomposition
• Peat: layers of undecomposed Sphagnum
2. N. Hemisphere Sphagnum habitat
Fens: less acidicinput: precipitation, groundwater, streams
Bogs: more acidicinput: precipitation only
• Sphagnum: relatively less abundant
• In Black Hills: rare habitat w/ rare plants
Fens Bogs• Sphagnum: dominant
• In Black Hills: absent
• Boreal forest: glaciated northern hemisphere areas
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Bog formation (glaciated lakes) Step 1: (Pothole) lake• Sphagnum grows from edges
• Groundwater feeds lake
Step 2: Floating bog• Sphagnum grows over water
• Peat builds on bottom, blocks groundwater
Loose floating bog (Minnesota 2018)
Step 3: Grounded bog• Peat fills lake
• Slow-growing forest develops
Bogs and unusual plants• Acid-loving plants
• Carnivorous plants
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Cranberries (acid loving)Sundew (carnivorous) Pitcher plants (carnivorous)
Why are carnivorous plants in bogs?• Low nutrient
• Acidic
Bogs and historical artifacts• Bog butter
• Bog bodies
Bog butter
preserved dairy or animal fat(not rancid)
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Bog bodies
8000 YA - 1940s,usually violent deaths
Why did butter and people mummify?• Cold
• Acidic
• Anaerobic
è Very slow decomposition
Peatlands and carbon dioxide• Major carbon sequestration: carbon "locked" in peat
• Unknown peatland amount and location
• Destroyed by agriculture, development, fire