lecture 5: terrestrialization II and seed-free plants

Question 1

seed-free / seedless plants

Answer 1

◆ an embryophyte (aka land plant)
◆ vascular plants
- include lycophytes (club mosses, spikemosses, quillworts); monilophytes (ferns, horsetails, whisk ferns)
- complex vascular system
- specialized cells/tissues transport water, sugars, and nutrients

Question 2

bryophytes

Answer 2

◆ one of the main embryophytes (land plants)
◆ non-vascular
◆ includes liverworts, mosses, and hornworts
- mosses: found in moist forests and wetlands, tolerant of desiccation
◆ gametophytes rule its life cycle – sporophytes are dependent on gametophyte for nutrition
◆ innovations: phyllids, rhizoids, gametangia (antheridia/archegonia), embryo, cuticle, sporangia

Question 3

desiccation

Answer 3

drying out

Question 4

phyllids and rhizoids

Answer 4

*two of the innovations of bryophytes to allow it to get water

phyllids:
◆ thin, leaf-like growths that absorb water through direct in contact with ground or trapped moisture
- NOT leaves

rhizoids:
◆ long tubular single cell or filaments that do some water/nutrient uptake but mainly function to anchor plant
- NOT roots
- associate with arbuscular mycorrhizal fungi

Question 5

gametangia (antheridia/archegonia)

Answer 5

new multicellular protective tissues where gametes form
- goal: protect the gametes and new sporophyte as they develop
- key innovation of bryophytes

◆ antheridia – gametangia that produce sperm
◆ archegonia – gametangia that produce eggs

• short sporophytes develop on gametangia of liverworts

Question 6

embryo

Answer 6

the zygote (fertilized egg) is also retained in the archegonium and develops embedded in and dependent on nutrition from maternal tissue

• goal: protect the gametes and new sporophyte as they develop
• key innovation of bryophytes

Question 7

cuticle

Answer 7

new waterproofing for the sporophyte generation that is waxy

• goal: make the sporophyte and spores more waterproof for airborne life
• key innovation of bryophytes

Question 8

sporangia

Answer 8

a receptacle in which asexual spores are formed

Question 9

sporopollenin

Answer 9

a polymer that prevents desiccation of charophyte zygotes to make plant spores also resistant to harsh environments. and capable of dispersal by air

• goal: make the sporophyte and spores more waterproof for airborne life
• key innovation of bryophytes

Question 10

sporophyll

Answer 10

leaves that form sporangia

Question 11

sorus (pl. sori)

Answer 11

clustered groups of sporangia

Question 12

peat (moss)

Answer 12

◆ type of moss –> bryophyte –> embryophyte
◆ major component of deposits of peat (partly decayed organic material found in huge, boggy wetlands)
◆ carbon-rich peat has long been harvested for fuel
- store 25% of all soil carbon
- release carbon in a relative instant despite taking 100s-1000s of years to develop
◆ peat moss
- used as a soil condition because moss cells can abosorb 20x their weight in water
◆ connection to climate change
- becoming susceptible to fires
- tropical peatlands are burned and drained to make way for palm oil plantations
- peatland protection and rewetting = highly important solution to climate change