Bryophytes Flashcards
What are the three phyla?
Liverworts, Hornworts and mosses
What derived traits are shared with tracheophytes?
Multicellular embryos, apical meristems
What features are lacking in bryophytes that are present in tracheophytes?
Roots, leaves and lignified transport system
What is the dominant stage?
Gametophyte
What is a protonema?
Characteristic of germinating moss spores, grow into a mass of filamentous cell with a large surface area
What is the gamete producing structure know as?
Gametophore - bears the gametangia
Why do gametophytes generally form ground hugging carpets?
Cant support a tall structure
Why is the structure very thin?
So they can distribute nutrients without a vascular system
What are rhizoids?
Long tubular single cells, not composed of toissues, role id to anchor the plants
Why are most bryophytes found in moist habitats?
Because they require a thin film of water for reproduction to take place
How are sporophytes of bryophytes different than in tracheophytes?
Cannot live independently, require the gametophyte for survival, smallest sporophyte of all extant plant groups
What are the features of the sporophyte?
A foot, seta and sporangium (capsule)
What is the role of the foot?
Embedded in the archegonia, obtains nutrients from the gametophyte
What is the role of the seta?
Conducts the materials from the foot to seta, elongated in some to elevate sporangium for better dispersal
What is the role of the sporangia?
uses nutrients to produce spores by meiosis
What is the peristome?
Ring of teeth like structures on capsule, that open under dry conditions and close in wet, to allow spores to be dispelled gradually
What feature do hornworts and mosses have that is lacking in liverworts?
Specialised stomata for exchange of co2 and oxygen and to minimise water loss
What are homospores?
Spores of one kind, not differentiated by sex
What is zooidogamous?
type of plant reproduction in which male gametes (antherozoids) swim in a film of water to the female gametes (archegonium)
What is exoscopic embryogeny?
apex of embryo pointed towards the neck of archegonium
How are the spores dispersed?
By wind
What are epiphytes?
Can grow on another plant
How are bryophytes protected from UV radiation?
Phenoilc compounds
Where do bryophytes colonise?
Bare rocks and soil surfaces for trees
What happened in the mid ordovician?
First land plants evolve, bryophytes widespread
What happened in the early silurian?
Tracheophytes evolve and overtake bryophytes in dominant vegetation
What happened in the mid Devonian?
trees and forests evolved, give rise to new habitats for bryophytes to exist
How are bryophytes important in the ecosystem?
Reduce the loss of nitrogen, can retain concentration in the soil
