Lecture 1 Flashcards
benefits for plants living on land:
- unfiltered sunlight
- more CO2
- nutrient-rich soil
when did small plants, fungi, and animals emerge on land?
500 MYA
challenges for plants living on land:
- scarity of water
- lack of structural support against gravity
what do plants supply?
fixed carbon ( sugars i.e. energy) and oxygen; they are the ultimate source of food eaten by land animals
plants are not descended from ______ but share a common ancestor with them.
charophytes
sporopollenin:
a layer of durable polymer in charophytes that prevent exposed zygotes from drying out
is sporopollenin convergent or divergent from charaphytes to the plants?
divergent; found in plant spore walls
the gametophyte produces
haploid gametes by mitosis
the sporophyte produces
haploid spores by meiosis
spores develop into
gametophytes
heterosporous:
all seed plants
homosporous:
all non-seed plants
dioecious:
higher order plants
monecious:
early lineages
where is the embryo?
diploid embryo is retained within the tissue of the female gametophyte
how are nutrients transferred from parent to embryo?
placental transfer cells
embryophytes:
plants are called this because of the dependency of the embryo on the parent
where do the sporophytes produce spores?
in the sporangia
sporocytes:
diploid cells that undergo meiosis to generate haploid spores
what do spore walls contain?
sporopollenium
sporopollenin:
makes them resistant to harsh environments
where are gametes produced?
in the gametangia which developed from the spores released from the sporangia
female gametangia::
archegonia
what do the archegonia produce?
a single nonmotile egg
male gametangia::
antheridia
what does the antheridia do?
produce and release sperm
where is the egg fertilized?
within an archegonium
apical meristems:
plants sustain continual growth in length by repeated cell mitotic division
cuticle:
a waxy covering of the epidermis
stomata:
specialized cells that allow for gas exchange between the outside air and the plant
bryophytes:
nonvascular non-seed plants AKA mosses
do bryophytes form a monophyletic group?
no
phylas of bryophytes:
mosses, liverworts, hornworts
–earliest lineages to diverge from the common ancestor of land plants
mosses:
capable of inhabiting diverse and sometimes extreme environments, but common in moist forests and wetlands
peat moss:
sphagnum::forms extensive deposits of partially decayed organic material::can be used as a source of fuel
what inhibits the decay of moss?
low temp., pH, and oxygen level of peatlands
are gametophytes or sporophytes larger and longer-living?
gametophytes
a spore germinates into a gametophyte composed of a
protonema and one or more gamete-producing gametophores
rhizoids:
anchor gametophytes to substrate
a sporophyte consists of:
a foot, a seta(stalk), and a sporangium, plus a capsule
what does the capsule do in sporophytes:
discharges spores through a peristome
who arose after mosses and gave rise to vascular tissue?
fern lineages
two types of vascular tissues:
xylem and pholem
xylem:
conducts most of the water and minerals and includes tube-shaped cells called tracheids
lignin:
strengthen water-conducting cells in the xylem and provide structural support
phloem:
cells arranged into tubes that distribute sugars, amino acids, and other organic products
Vascular tissue allowed for increased height, which provided an evolutionary advantage
roots:
are organs that anchor vascular plants and enable vascular plants to absorb water and nutrients from the soil
mycorrhizae:
symbiotic associations between fungi and plants may have helped plants without true roots obtain nutrients and that symbiotic relationship is still seen today
