25.4 Seedless vascular plants

Question 1

Tracheophytes!

Answer 1

Form 90% of vegetation
are all vascular plants
can achieve enourmous heights (light competition)

Question 2

Seedless tracheophytes!

Answer 2

2n sporophyte is the dominant one
gametophyte is incospicious yet still an independent organism
still depend on water for fertilization

Question 3

Xylem

Answer 3

• water, mineral and growth factor transports
• conducting cells (tracheids) are lignified
• filler tissue (parenchyma)
• lignin (is a complex impermeable to water polymer)

Question 4

Phloem

Answer 4

• Transports sap (sugars/proteins)
• has sieve elements (conducting cells)
• has support cells

Question 5

Root

Answer 5

• appeared later than vascular tissue
• transferred water and minerals
• penetrates deeply to dinf water and anchor plant
• form micorrhizae to increase water and mineral absorption

Question 6

True leaves

Answer 6

• increased surface area
• 2 types of morphology (that had independent evolutionary growth)
  
  • Microphyll leaves (1 unbranced vein in leaf center)
    
    • present in club mossess
  • Megaphyll lealves (multple, branced veins in leafs)
    
    • formed independently many times

Question 7

Sporophylls

Answer 7

• structurally modified leaves to bear sporangia ( Pine cones / flowers)

Question 8

Strobili

Answer 8

• cone-like structures that contain sporangia (pine-cones in conifers)

Question 9

Club mosses (lycopodiophyta)

Answer 9

• dominated the carboniferous era
• alternation of generations but dominant sporophyte
• gametophytes don’t depend for nutrients
  
  • some are mycorrhizal
• sporophylls are arranged in strobili
• can be homo or heterosporous

Question 10

Monilophyta classess

Answer 10

• Equisetopsida (horsetails)
• Psilotopsida
  
  • Psilotaceae (whisk-ferns)
  • Psilotum (ferns)

Question 11

Horse tails (equisetopsida)

Answer 11

• stem has joints/nodes
• leaves and branches come out as whorls (evenly spaced)
• most photosynthesis in stem
• silica in epidermalcells make it sturdy
• rhizomes anchor it (underground stems)
• homosporous and bisexual gametophyte

Question 12

Whisk ferns (psilotaceae)

Answer 12

• no roots or leaves (reduction)
• photosynthesis in stems
• yellow knobs at the tip (sporangia)

Question 13

Ferns (psilotum)

Answer 13

• «moidz, dhsfrf plsvrd
• moist, shaded places
• devonian era and expanded into the carboniferous
• have FRONDS (large compound leaf of sporophyte)
• Fronds are photosynthetic and have reproductive organs

Question 14

Stem and tip of ferns

Answer 14

• stem is buried as a rhizome
  
  • Adventitious organs (unsual place growth)
• tip of the developing fern front
  
  • rolled into a crozier / fiddlehead
  • it unrolls as it develops
• alternation of generations but bisexual

Question 15

Fern reproduction

Answer 15

Most ferns are homosporous
- sori form underneath fronds as small clusters where sporangia develop
- spores are released into the air, landing on suitable substrates
- spores germinate to form a heart-shaped gametophyte (easy swimming) which have thin rhizoids
- gametophyte have both gametangia (antheridium and archegonium

Question 16

Importances of seedless plants

Answer 16

• first colonizers
• mosses are a bioindicator for the level of pollution in the enviornment (entire exposed surface for absorbing)
• ferns weather rock

Question 17

Sphagium

Answer 17

Dried peat moss
- common fuel in europe
- maintain moisture for floral arrangements
- pretty, dietary and medicinal

Question 18

Secondary compounds

Answer 18

Secondary compounds are adaptations of plants to their environmental challenges