bio lecture 4

Vocabulary flashcards covering bryophytes (liverworts, mosses, hornworts): life cycle, anatomy, reproduction, ecology, and phylogeny.

Bryophytes

Nonvascular land plants comprising liverworts, mosses, and hornworts; lack true roots, stems, and leaves and rely on diffusion/osmosis for water and nutrient movement.

Alternation of generations

Life cycle with two multicellular stages—haploid gametophyte and diploid sporophyte—an important trait of land plants.

Gametophyte

Haploid (n) generation that produces gametes; in bryophytes it is typically the dominant, photosynthetic stage.

Sporophyte

Diploid (2n) generation that produces spores via meiosis; in bryophytes it is usually dependent on the gametophyte for water and nutrients.

Antheridium

Male reproductive organ that produces sperm (n) in bryophytes.

Archegonium

Female reproductive organ that produces eggs (n) in bryophytes.

Sporangium

Structure in the sporophyte where meiosis occurs to form haploid spores.

Spore

Haploid reproductive cell that germinates to form a new gametophyte.

Protonema

Early filamentous stage of the moss gametophyte arising from a germinating spore.

Rhizoid

Hair-like, root-like structures used for anchorage and limited water absorption.

Hydroid

Water-conducting cell in mosses; lacks true vascular tissue.

Peristome teeth

Hygroscopic teeth at the opening of the moss capsule that control gradual spore release in response to humidity.

Calyptra

Cap-like tissue covering the moss capsule, derived from the gametophyte.

Seta

Stalk that elevates the moss capsule; part of the sporophyte.

Operculum

Cap that covers the moss capsule and detaches to release spores.

Elater

Hygroscopic structures aiding spore dispersal by responding to humidity (common in liverworts and some bryophytes).

Gemmae

Asexual propagules produced in liverworts (in splash cups) for vegetative reproduction.

Sphagnum

Peat moss; forms peatlands, a major global carbon sink storing hundreds of gigatons of carbon.

Peatland

Waterlogged, acidic, anaerobic wetlands that slow decay and store large amounts of carbon.

Hornworts

Bryophyte lineage with horn-like sporophytes, cells often with a single chloroplast, basal meristem, and open stomata; host cyanobacteria symbiosis.

Cyanobacteria Nostoc symbiosis

Nitrogen-fixing cyanobacteria living in hornwort cavities, contributing fixed nitrogen.

Stomata

Pores for gas exchange; hornwort sporophytes have permanent stomata, while liverworts lack true stomata.

Liverworts air pores

Simple openings for gas exchange in liverworts; lack true stomata.