Land Plants: Bryophyte Diversity

Question 1

What is polytomy?

Answer 1

a node on a phylogeny where more than two lineages descend from a single ancestral lineage

Question 2

What is the stage in a plant life cycle that is not present in a green alga life cycle?

Answer 2

multicellular sporophyte (2n) stage

Question 3

Are bryophytes vascular or non-vascular plants?

Answer 3

non-vascular plants

Question 4

What is the relation of Bryophytes to algae and vascular plants?

Answer 4

considered transitional between the two

Question 5

What conditions do Bryophytes live in?

Answer 5

moist locations (no vascular tissues or root system), require water for reproduction
found on all continents

Question 6

How does fertilization and dispersal work for Bryophytes?

Answer 6

water (sperm) and air (spores)

Question 7

What are synapomorphies?

Answer 7

a derived or changed character state shared by two or more lineages in a particular clade. an indicator of common ancestry

Question 8

What are 3 synapomorphies of bryophytes and vascular plants?

Answer 8

antheridia (sperm-producing) and archegonia (egg producing) with sterile protective layer
retention of zygote and multicellular embryo within female gametophyte
multicellular, diploid sporophyte

Question 9

How did alteration of generations create differences between Bryophytes and Vascular plants?

Answer 9

bryophytes - gametophyte dominant, free-living
sporophyte smaller, dependent on gametophyte
vascular plants - sporophyte dominant, free-living
gametophyte smaller, most are dependent on sporophyte

Question 10

What are the 3 adaptations for bryophytes life on land?

Answer 10

thin thallus (main body) - facilitates uptake of water and CO2
surface pores (analogous to stomata) - gas exchange
cuticles (waxy surface layer to prevent water loss)

Question 11

What is the antheridia?

Answer 11

sperm

Question 12

what is the archegonia?

Answer 12

egg

Question 13

how does sexual reproduction work in Bryophytes?

Answer 13

after fertilization zygote (2n) remains in archegonium, nutrition from female gametophyte
sporophyte (2n) - dependent, attached to female gametophyte
Sporangium - produces haploid spores

Question 14

What are the 3 phyla (or lineages) of Bryophytes?

Answer 14

Hepatophyta - liverworts
Anthocerophyta - hornworts
Bryophyta - mosses

Question 15

Where are Hepatophyta (liverworts) found?

Answer 15

in moist habitats, growing on tree trunks and in moist soil
roughly 8000 species

Question 16

describe the structure of a liverwort (hepatophyta)?

Answer 16

‘leafy’ thallus (gametophyte) only 10-30 cells thick
upper surface photosynthetic - contains pores for gas exchange (analogous to stomata)

Question 17

What is a spieces of Hepatophyta?

Answer 17

Marchantia

Question 18

Marchantia have elaters, what are these?

Answer 18

elongate, helically arranged hydroscopic cells (absorb moisture), aid in spore dispersal

Question 19

What type of reproduction do Marchantia carry out and how?

Answer 19

asexual reproduction via gemmae formation - the gemmae can transform into new gametophyte plants

Question 20

Where are features of Antherocerophyta (Hornworts)?

Answer 20

gametophyte - thallus, rosette
cavities inhabited by cyanobacteria - nitrogen fixation
roughly 100 species

Question 21

What are the 3 major groups of Bryophyta (mosses)?

Answer 21

Sphagnidae - Sphagnum (peat mosses)
Andreaeidae - granite mosses
Bryidae - ‘true’ mosses

Question 22

Where is Sphagnum (species of moss) found?

Answer 22

in bogs and marshes

Question 23

What is a feature of Sphagnum making it unique for peat bogs?

Answer 23

holds 20x dry weight in water

Question 24

What is industry can Sphagnum also be used in? as what?

Answer 24

horticulture - soil additive, planting medium, packing material for roots

Question 25

How can Sphagnum be used in medicine?

Answer 25

decay resistant phenolic compounds giving it antisepctic properties (wound dressing) (probs WW1)

Question 26

WHat does the decay resistant phenolic compounds of Sphagnum do to soil?

Answer 26

increases acidity of soil - release H+ ions (bogs pH < 4)

Question 27

What is the significance of Sphagnum peat bogs (size and potential effect on planet)?

Answer 27

makes up only 2-3% of total land surface
- large carbon sinks
- warmer temps could lead to increased rates of decomposition leading to more CO2 in atmosphere

Question 28

What is a species of true mosses?

Answer 28

Polytrichum (common haircap moss)

Question 29

What are features of Polytrichum (Common Haircap Moss)?

Answer 29

evergreen perennial plant up to 1.5ft tall, stems of individual plants are erect to sprawling
found in moist habitats

Question 30

Describe the life cycle of mosses

Answer 30

spores produced and mature forming female and male gametophytes
egg is produced in archegonia, sperm is produced in antheridia
fertilization occurs and zygote (2n) forms
zygote becomes an embryo
embryo develops into a sporophyte
after maturation of sporophyte meiosis occurs and cycle begins again