26.2 Gymnosperms

Question 1

Gymnospermy

Answer 1

• naked seeds (paraphyletic) = not all form a single anscestor
• spearate female and male gametes
• pollination occurs by wind
• tracheid (transports water and solutes in vascular system
• seeds are exposed on cones or modified leaves

Question 2

Sporophylls

Answer 2

leaves that produce sporangia
- strobilus (tight arrangement of sporophyls around the central stalk (cones)
- integument (layer of sporophyte tissue that surrounds the megasporangium and the embry)
- dominant during the mesozoic era
- freshwater stare or nitrogen-poor osil
- so are in taiga where its cold and dry

Question 3

Evergreen conifers

Answer 3

• low photosynthesis till sunny spirng
• cannot shed parasites because don’t lose all leaves at once

Question 4

Reproduction

Answer 4

• Alternation of generations, dominant sporophyte in which the female gametophyte resides and reduced gametophytes
• hetero sporous
• male and female reproductive organs form in cones or strobili

Question 5

Monoecious

Answer 5

male and female sporangia in one plant (bisexual)

Question 6

Dioecious

Answer 6

male and femal sporangia in two plants (unisexual)

Question 7

Diveristy of gymnosperms

Answer 7

-4 phyla
-produce secondary cambium (partially speciallized for water transportation)
- same pattern of seed development amongst the phyla
- gnetophyla are the most closely related to angiosperms because they produce xylem

Question 8

Conifers (Coniferophyta)

Answer 8

• dominant phylum of gymnosperms
• most variety
• tall
• scale/needle-like leaves
  
  • for water evaporation and a thick cuticle that snow can slide off easily from making the tree less heavy
• at high altitudes where it is cold and dry
• some are deciduous (they shed annually) such as the europan larch or tamark
• they are harvested for paper pulp and timber
• tracheids are present but without the vessel element so they are “soft woods”

Question 9

Cycads

Answer 9

• mild climates (mistaken for palms)
• dominated the mesozoic and now face extinction

Question 10

Ginkophytes

Answer 10

• 1 species remains (Ginko bilobia)
• have fan-shaped leaves that show a dichotomous ventation pattern
• are deciduous
• are resistant to pollution
• male and female gametes on separate plants (dioecious)G

Question 11

Gnetophytes

Answer 11

• 3 genera (ephedra, gnetum, welwitschia)
• similar to angiosperms
• broad leaves

Question 12

Genus: Ephedra

Answer 12

• tropical and subtropical areas
• small shrubs and vines
  dry areas of the west coars
  ephidrine in leaves which is used as a decongestant in medicine in prescription drugs
  and have vessel elements