Bryophytes Flashcards
What are two ways that bryophytes deal with water loss?
Avoid or tolerate
What adaptations are present in bryophytes for dealing with evaporation?
Biochemical adaptations. Thin cuticle
Why couldn’t bryophytes have a thick cuticle to deal with water loss?
They need to absorb water and dissolved nutrients over the surface since they don’t roots, and it would limit gas exchange
What supporting structures are present in bryophytes?
Rhizoids
Why is there a limit to how big bryophytes can get?
They rely on diffusion for water and nutrient transfer
How do bryophytes have mechanical support?
Turgor pressure
How do bryophytes disperse their gametes?
Sperm are motile and require water to swim through and reach the egg
How do bryophytes disperse their spores?
Wind or projectile mechanisms
Which generation is dominant in bryophytes?
Gametophyte
What are the 3 phyla in the bryophytes?
Phylum Hepatophyta - liverworts
Phylum Antocerophyta - hornworts
Phylum Bryophyta - mosses
What are the characteristics of liverwort gametophytes?
Morphology can be thalloid or leafy, separate male and female gametophytes
What are archegoniophores?
Structure that supports the female reproductive parts
What are antheridiophores?
Structure that supports the male reproductive parts
Are bryophytes homosporous or heterosporous?
Homosporous-ish. The spores all look the same but they have separate male and female gametophytes
How do liverworts spread their spores around?
Use elaters, which coil up and then fling the spores into the air when they get wet
What are the traits of the sporophyte in hornworts?
Tall, narrow, and horn-like. Grows slowly
What are the traits of gametophyte in hornworts?
Thalloid, unicellular rhizoids
How do you differentiate a liverwort from a hornwort?
The sporophyte. Liverworts also have multiple chloroplasts per cell and hornworts only have one chloroplast per cell
What are the traits of the gametophyte in the mosses?
Leafy morphology, multicellular rhizoids. Has a “mop head” in the Sphagnidae
What are the traits of the sporophyte in the mosses?
Parasitic, non-photosynthetic
What is a protonema?
Thin strands of cells that grow into multiple gametophytes from the same spore
What does the sporophyte look like in the Sphagnidae? How are spores dispersed?
The sporangium at the top is dark and round, and disperses spores through the explosive operculum mechanism. It pulls itself tight, creates pressure inside then explodes
What are hydroids and leptoids?
Tissues found in the Bryidae that have similar functions to xylem and phloem, but are unrelated evolutionary
Are the gametophytes produced by a protonema genetically identical or different?
Genetically identical, they all come from the same spore
