25.3 Bryophytes

Question 1

Adaptations

Answer 1

• closest extant beings to early life
• small and tolerant to desiccation and have no tracheids
• All vegitative organs leaf-like, thallus and rhizoid belong to the gametophyte
• sperm have flagella
• has a sporangium

Question 2

Liverworts (Hepaticophyta)

Answer 2

• Closest to ancestor that moved on to land
• gametophytes have lobate green structures similar to shape of liver.
• non-stomatical openings for gas movement
• reproduce through alternation of generations
• gametangia sexes are on different plants
• have gammae for asexual reproduction
  
  • small complete pieces of plant produced
  • in a cup on the thallus surface that then fall and grow into a gametophyte

Question 3

Hornworts (Anthocerotophyta)

Answer 3

• Always near moisture
• blue-green short gametophyte DOMINANT
• pipe-like sporophyte characteristic
• stomata are abundant in the sporophyte
• thallus consists of 1 chloroplast and a meristematic base
• symbiotic relationship nitrogen fixing with cyanobacteria
• alternation of generations

Question 4

Mossess

Answer 4

> 10k species live thundra and tropical forests
- can fasten to substrate without penetrating frozen soil
- slow down erosion of rock
- stores moisture and soil nutrients
- provide shelter and nutrients to animals
- sensitive to air pollution and copper salts
- diminuitive gametophytes are DOMINANT
- non-vascular leaf-like structures absorb water

Question 5

Adaptations to dry land (mosses)

Answer 5

• stomata on sporophyte stem
• promitive vascular system on sporophyte stem
• anchored by rhizoids (root precursors)

Question 6

Protonema

Answer 6

• Single-celled filaments hugging the ground
• Made by the haploid gametophyte of mossess

Question 7

Gametophyte of mosses

Answer 7

Gametophore (stem & “ leaves”) + protonema
Rhizoids are at the base of the gametophore

Question 8

Gametangia of mossess

Answer 8

Gametangia of both sexes are on separate gametophores
- sperm swims from the neck to the venter and unites with the egg
- forming a zygote where the sporophyte is still attached to the gametophyte

Question 9

Seta

Answer 9

Transfers the nutrients from the foor to the capsule (which is a sporangium) of the sporophyte

Question 10

Peristome

Answer 10

Increases the spread of spores after the capsule tip falls off during spore dispersal
- the tissue around the capsules’ mouth have “teeth” that open-close resleasing spores depending on moisture levels periodically.