Week 10 Flashcards
what allowed for photosynthetic plants to move onto land
evolution of chloroplasts
Shared derived trait of Plantae
primary endosymbiosis
ancestors of Plantae
unicellular
similar to glaucophytes
glaucophytes
believed to be the sister group to plantae
Red algae
multicellular
has phycoerythrin and chlorophyll a
Green Algae
contain chlorophyll a and b
store energy as starch
synapomorphy
shared derived trait
Key trait of land plants
embryo that is protected by tissues of the parent plant
embryophytes
embryo that is protected by tissues of parent plant
Vascular plants
tracheophytes
well developed vascular system with fluid conducting cells
tracheids
fluid conducting cells
allows transport of water and materials
Nonvascular plants
have conduction cells, but no tracheids
form a clade
Land plants development
transport systems for water and nutrients
structural support
new ways to disperse gametes and progeny
adapt to dry conditions
Adaptions of land plants
cuticle
stomata
gametangia
embryos
pigments that protect against UV radiation
spores with thick walls containing a polymer that prevents drying and decay
mutually beneficial associations with fungi to promote nutrient uptake
Cuticle
waxy coating that slows water loss
stomata
closable openings that regulate gas exchange and water loss
Gametangia
organs that enclose gametes and prevent drying out
Land plants alternation of generations
includes multicellular dipliod and haploid stage
Gametes
produced by mitosis
Spores
produced by meiosis
develop into multicellular haploid organisms
How diploid zygote develops
by mitosis and cytokinesis into multicellular embryo which develops into mature diploid
sporophyte
multicellular dipliod plants
gametophyte
spores develop into multicellular hapliod plant
fusion of gametes
produces a diploid zygote which develops into a sporophyte
Nonvascular plants: location
moist habitats
bare rocks
dead trees
Nonvascular Plants characteristics
have thin cuticle
mostly small
no vascular system to transport water
minerals distributed throughout by diffusion
Nonvascular Plants - gametophyte
photosynthetic
Nonvascular reproduction
sperm must swim or be splashed by water to reach egg
Vascular system
specialised tissue for transport of water and materials throughout plant
Vascular tissue benefit
allowed land plants to spread to new environments and diversify rapidly
Xylem
conducts water and minerals from soil to aerial parts
Phloem
conducts products of photosynthesis to use or storage sites
lignin
in the cell walls
provides structural support promoting growth
Branching benefit
allows more spore production and complex growth patterns
Euphyllophytes
clade consisting of monilophytes and seed plants
have overtopping growth
overtopping growth
one branch differentiates from and grows beyond the others
Megaphylls
more complex leaf, may have arisen from flattening of branch tip
Megaspore
develops into female gametophyte
Microspore
develops into male gametophyte
Seeds
provide secure and lasting dormant stage
Trend in plant evolution
sporophyte became less dependent on gametophyte, gametophyte became smaller
pollination
arrival of pollen grain near female gamete
pollen tube
grows from grain and digests to fertilisation
seed makeup
seed coat
haploid tissue
embryo
seed coat
developed from tissues of diploid parent
protect from drying, predators and other damage
Haploid tissue
provides nutrients for developing embryo
secondary growth
increasing diameter of roots and stems by growth of xylem
Gymnosperms
seed plants that dont form flowers or fruits
ovules and seeds not protected
only have tracheids within xylem
Angiosperms
reproductive organs are flowers
seeds enclosed in fruits
ovules and seeds enclosed in modified leaf
carpel
modified leaf
XYlem of angiosperms
has vessel elements
inflorescence
groups of flowers
Stamens
male gamete
composed of filament and anther
Carpels
female gamete
base contains ovules
Style
stalk of carpel
Stigma
place where pollen lands
Perfect flowers
have both male and female gametes
imperfect flowers
2 types, male and female
monoecious
male and female in same plant
Dioecious
male and female in different plants
Double fertilisation
each pollen grain has 2 male gametes, one combines with egg and other combines with two other hapliod nuclei to form triploid cells
Triploid cells
gives rise to endosperm
nourishes embryo
Cotyledons
seed leaves
can absorbs and digest endosperms or become photosynthetic
Simple fruit
developed from single carpel or fused carpels
Multiple fruit
forms from flower cluster
monocots
1 cotyledons
eudicots
2 cotyledons
Fungi
live by absorptive heterotrophy
muliticellular and unicellular
digestive enzymes are secreted outside body to break down food
molecules than absorbed to cells
saprobes
absorb nutrients from dead matter
parasites
absorb nutrients from living hosts
fungi evolution
from unicellular protist with flagellum
Myecelium
body of fungi
hyphae
individual tubular filaments
absorb nutrients from living plants
septate hyphae
subdivided by incomplete crosswalls
coenocytic
no septaa but many nuclei
Fungi function
decompose dead organisms, waste and recycle minerals
decompose cellulose and lignin
facultative parasites
grow on living organisms or independently
obligate parasites
grow only on specific living hosts
haustoria
branching projections that push through cell walls into cell membrane and absorb nutrients
predatory fungi
trap protists and animals
secrete sticky substances and hyphae grow into trapped prey
symbiotic relationships
partners live in close, permanent contact with each other
mutualistic relationships
benefits both partners
Lichens
associations of fungi with unicellular green algae
Myocorrhizae
associations of fungi and plant roots
Ectomycorrhizae
fungi unwraps around individual cells in root but doesnt penetrate cells
Arbuscular mycorrhizae
penetrate root cell walls forming treelike structures inside cell, outside plasma membrane
Endophytic fungi
live in aboveground plants but dont harm plant
produce alkaloid compounds that are toxic to animals
forms of fungi asexual reproduction
haploid spores produced in sporangia
haploid spores form tips of hyphae
cell division or budding
simple breakages of mycelium
Mating types of fungi
no male and female
have distinct mating types
lichens
highly sensitive to air pollution
fungi - carbon cycle
critical to carbon cycle because of role breaking down dead organic matter