Lecture 16 Flashcards
what organism in the kingdom plantae doesn’t have seeds or a vascular system
bryophytes
what organisms are bryophytes
mosses, liverworts, hornworts
what organism in the kingdom plantae have seeds and a vascular system
ferns, clubmosses, whisk ferns, horsetails
what are gymnosperms and angiosperms considered
seed plants
what are some of the main characteristics of bryophytes
seedless; nonvascular; most found in moist habitats; wide range of habitats; important initial colonizers
what are gametophytes
haploid generation, gamete-producing
what are sporophytes
diploid generation, spore-producing
what are the two stages of alternation of generation
gametophyte and sporophyte
how are bryophytes similar to vascular plants
presence of male and female gametangia with a protective layer; retention of zygote and embryo within archegonium; multicellular diploid sporophyte; multicellular sporangia; spores with walls containing sporopollenin; tissues produced by apical meristem
what is the strongest structure that is naturally made
sporopollenin
how are bryophytes different from vascular plants
no vascular tissues; conducting tissue cell walls not lignified; bryophytes have dominant gametophyte
what type of structure and reproductive parts do bryophytes have
no true stems, leaves, or roots; some have cuticle with structures analogous to stomata; usually attached to substrate by rhizoids
what is the function rhizoids
anchor plant; not used for water transport; often have fungal or cyanobacterial symbionts
how are cells connected in bryophytes
plasmodesmata
how do bryophytes reproduce
asexually by fragmentation and gammae
which cells are flagellated
sperm cells
what is the antheridium
male reproductive structure; usually stalked; sterile jacket layer surrounding spermatogenous cells; each spermatogenous cell forms one biflagellated sperm cell
what is the archegonium
female reproductive structure; flask-shaped; surround a single egg; release chemicals to attract sperm
where does fertilization occur
archegonium
what process does the zygote undergo
undergoes mitosis to generate embryo and eventually mature sporophyte
where is the plasmodesmata not located
no plasmodesmata between sporophyte and gametophyte
why is there no plasmodesmata between the sporophyte and gametophyte
Placenta- several transfer cells
what characteristics does a mature sporophyte have
foot in archegonium; seta (stalk); capsule (sporangium)
what is an embryophyte
term for all plants; multicellular, matrotrophic embryo; produce many-celled diploid sporophyte
what does sporopollenin do
most decay and chemical resistant biopolymer
which organisms form Protonemata
Protonemata are formed in all mosses and some liverworts but not in hornworts.
what are charophytes
class of green algae most closely related top plants
what are the three phyla in bryophytes
Phylum Hepatophyta; Phylum Anthocerophyta; Phylum Bryophyta
what phyla are liverworts in
hepatophyta
what are some characteristics of liverworts
small; most gametophytes develop directly from spores; some have protonema first
what are the two clades of liverworts
clades are either complex thalloid types or “leafy” simple types
what type of liverwort is merchantia
complex thalloid
what are some characteristics of merchantia
gametophytes unisexual; distinguished by gametophores; specialized spore dispersal mechanism; gemma cups (asexual reproduction) – produce gemmae
where are leafy liverworts found
abundant in tropics & subtropics (high humidity or rainfall
grow on leaves, bark, other plant surfaces)
what phyla are hornworts in
Anthocerophyta
what are the characteristics of gametophytes in hornworms
somewhat similar to thallose liverworts; cells usually have one large chloroplast; usually 1-2 cm across; some unisexual
what are the characteristics of sporophytes in hornworms
foot and capsule/sporangium; meristem between foot and sporangium (means that it can’t not branch); green with cuticle and stomata
what are the three classes of bryophyta
Sphagnidae (peat mosses); Andreaeidae (granite mosses);
Bryideae (“true mosses”)
what are some characteristics of peat moss
diverged early from main line of moss evolution; distributed worldwide; distinctive sporophytes; common asexual reproduction through fragmentation
how are peat mosses different than other mosses
unusual protonema; morphology of gametophyte (“moplike” head, leaves one cell layer thick, dead leaf cells fill with water) explosive spore dispersal (operculum)
what is the protonema
the first stage of development of the gametophyte
what is the operculum
cap that bursts open and allows spores to escape
what class does granite moss belong too
andreaeidae
what are some characteristics of granite moss
small blackish-green or reddish-brown tufts; grow on rocks in mountainous or arctic regions; unique spore discharge mechanism
what class does true moss belong to
Bryidae
what are some characteristics of true moss
resemble filamentous green algae (protonema) but have slanted cross walls; multicellular rhizoids
leaves normally only one cell layer thick
what are hydroids
water-conducting cells in stems of gametophytes and sporophytes; resemble tracheids but cell walls not lignified
what are leptoids
food-conducting cells
what is the sexual reproduction like in bryidae
unbranched sporophyte (embedded in gametophyte, placenta; usually have stomata; as matures, turns brown) specialized spore dispersal (operculum bursts off; peristome)
The peristome is unique to which class
bryidae
