Plant diversity Flashcards
challenges of plant life on earth**
a scarcity of water and lack of structural support against gravity
describe the adaptations that allowed plants to colonize earth**
protection from desiccation(drying out)
alternation of generations
vascular tissue
what are the traits shared by green algae and land plants**
what are the main characteristics of land plants**
describe major steps in the life cycle of plants**
explain the phylogenetic relationships of land plants**
list the major groups and classes of land plants**
describe the main features of bryophytes**
What is the ecological and economical importance of moss**
describe the traits of seedless non-vascular and vascular plants**
describe innovations that allowed seed plants to reproduce in the absence of water**
list the four groups of modern-day gymnosperms and provide examples of each**
explain why angiosperms are the dominant form of plant life in most terrestrial ecosystems**
describe the life cycle of typical angiosperm **
Sporopollenin
a polymer that prevents zygotes from drying out
also found in plant spore walls
What are green plants referred to as
streptophytes
what are land plants called
embryophytes
what are the two groups that land plants are classified into
non-vascular and vascular
What are the two major groups of green algae
chlorophytes and charophytes
charophytes are the closest relatives of plants
reproduce sexually and asexually
evidence of algal ancestry
plants and some algae are multicellular, eukaryotic, photosynthetic autotrophs
some algae, like plants, have cellulose in their cell walls and chloroplasts containing chlorophyll a and b
cellulose-synthesizing membrane proteins are arranged in rings, rather than linear sets
structure of flagellated sperm
sequence similarities in nuclear, chloroplast, and mitochondrial DNA
alternation of generations(haplodiplontic cycle)
type of plant life cycle consisting of multicellular forms that give rise to each other in turn
has two stages: multicellular diploid stage and haploid stage
multicellular diploid stage
the whole plant is called the sporophyte
all the cells in the sporophyte plant are diploid at first
only the sporocytes go through meiosis to produce haploid cells called spores
where are sporocytes located
sporangium
In multicellular diploid stage what happens when meiosis is complete
spores are still in the sporangium, then it cracks open and releases the spores
Multicellular haploid stage
is called the gametophyte
haploid spore is released from the sporangium, it lands on moist soil and germinated until the whole gametophyte is grown
a few cells in an organ called gametangium to go through mitosis to form gametes
sperm will swim to the egg and the gametes fuse to form a diploid zygote
zygotes grow by mitosis into the next sporophyte plant
alternation of generation happen between what and explain the process
between the 1n gametophyte and 2n sporophyte. mitosis occurs in both gametophyte and sporophyte generations. diploid sporophytes produce haploid spores by meiosis, while haploid gametophytes produce gametes by mitosis
multicellular, dependent embryos
the diploid embryo is retained and protected within the tissue of the female gametophyte
nutrients are transferred from parent to embryo through placental transfer cells
plants are called embryophytes because of this dependency of the embryo on the parent
what are seedless non-vascular plants known as
bryophytes or non-tracheophytes
they are the closest living descendants of the first land plants and require water for sexual reproduction
bryophytes
simple, but highly adapted to diverse terrestrial environments
gameophyte- the most noticeable part, and the photosynthetic part
sporophytes are small and dependent
what are the tree phyla of bryophytes
liverworts, hornworts, and mosses
what is the life cycle of liverworts
the antheridia and archegonia are produced on separate gametophytes…
what are characteristics of hornworts
they grow a tall and slender sporophyte
What do mosses produce
spore-producing sacs called sporangia that grow at the ends of long thin stalks
What are seedless vascular plants called
tracheophytes
describe tracheophytes
most are homosporous meaning they produce one type of spore
what is the first vascular land plant
cooksonia
vascular plants
dominant group of land plants
diploid sporophyte is the dominant phase of the life cycle in tracheophytes
what do vascular plants include
lycophytes(club mosses)
pterophytes(ferns, whisk ferns, and horsetails)
seed plants (didnt evolve until mesozoic era)
what the vascular tissues
xylem and phloem
xylem
consists of dead cells called tracheids that form a tube
conducts water and dissolved minerals upward from the roots
phloem
consists of living cells
conducts sucrose and hormones throughout the plant
in club mosses what are sporangia arranged in
clusters called strobili
what do pterophytes include
whisk ferns- visible green stems with knob-shaped sporangia
horsetails, named for the brushy appearance of the sporophyte
ferns
on ferns what are sori
appear as small bumps on the underside of a fern frond
what is the reproductive cycle of a fern
produce distinctive sporangia in clusters called sori on the back of the fronds. diploid spore mother cells, sporocytes(2n), in sporangia produce haploid spores(n) by meiosis
every spore germinates into bisexual gametophyte archegonium and antheridium on the same plant
flagellated sperm
what do seed plants include
includes embryo, food for the embryo, and a seed coat
allows the clock to be stopped to survive harsh periods before germinating
naked seeds first then later development of fruits enhanced dispersal
all seed plants are _____
heterosporous
heterosporous
they have different sporangia that produce different spore types
male gametophytes have what
pollen grains
dispersed by wind r pollinator
no need for water
female gametophytes have what
develop within an ovule
enclosed within diploid sporophyte tissue in angiosperms
What are the 5 phyla of extant seed plants
coniferophyta
cycadophyta
genetophyta
ginkophyta
anthophyta
phylum coniferophyta
most diverse
pines spruces firs cedars and other
found in colder and sometimes drier regions of the world
leaves have thick cuticle and recessed stomata to retard water loss
leaves have canals with resin to frighten insect and fungal attacks
what is the life cycle of conifers
pollen from male cones blows up into upper branches where it fertilizes female cones
the megaspore develops into the female gametophyte as the pollen tube slowly grows toward it, eventually fusing with the egg and delivering a male nucleus, which combines with the female nucleus of the mature egg
phylum Cycadophyta
slow-growing gymnosperms of tropical and subtropical regions
sporophytes resemble palm trees
have the largest sperm cells of all plants
phylum gnetophyta
only gymnosperms with vessels in their xylem
contain three genera
welwitschia
ephedra
gnetum
phylum ginkgoophyta
only one species remains
flagellated sperm
angiosperms
flowering plants: seeds that develop inside chambers that originate within flowers
what is the angiosperm life cycle
anthers and carpels are structures that shelter the actual gametophytes: the pollen grain and embryo sac. double fertilization is a process unique to angiosperms
