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