Unit 3 PAL Flashcards
when did plants move to land?
450-500 mya
list 3 challenges that plants faced on land
- dessication (drying out)
- water and nutrient supply and transport
- distributing gametes and progeny
how did plants avoid dessication?
- cuticle
- stomata
waxy coating that slows water loss
cuticle
tiny pore; regulates gas exchange
stomata
how did plants solve the water and nutrient transport problem?
by not getting too big and with vascular structures
how do nonvascular plants distribute gametes
flagella (need H2O)
how do nonvascular plants distribute progeny
haploid spores (wind)
how do vascular (SEEDLESS) plants distribute gametes
flagella (need H2O)
how do vascular (SEEDLESS) plants distribute progeny
haploid spores (wind)
how do vascular (SEED) plants distribute gametes
pollen (wind)
how do vascular (SEED) plants distribute progeny
diploid seeds (wind/seed, predation)
how do vascular (flowers) plants distribute gametes
pollen (wind./pollinators)
how do vascular (flowers) plants distribute progeny
diploid seeds (wind, seed, predation)
what are the similarities between liverworts, mosses, and hornworts?
- lack true leaves, stems, and roots
- lack a vascular transport system
- have a thin cuticle (or nonexistent)
- live in a moist habitat
describe liverworts
- 9000 species
- gametophyte dominant
- reproduce both sexually and asexually (gemmae)
describe mosses
- 15000 species
- have stomata
- gametophytes begin as branched, filamentous structures called protonema
- peat
describe hornworts
- 100 species
- gametophytes are flat plates of cells
what are the components of the vascular system?
xylem and phloem
what is the specific function of xylem?
- transports H2O and minerals from soil
- one way flow only
- cell walls have lignin for support
what is the specific function of phloem?
- transports products of photosynthesis
- two way flow
monocot stem
vascular bundles scattered
monocot root
vascular bundles in ring (in center)
dicot stem
vascular bundles in ring
dicot root
xylem forms “x”, phloem around it
What is a new way that vascular plants were able to meet the challenges of water/nutrient transport and support?
got taller–> able to get more light and was beneficial for spore dispersal
What are the three phyla of seedless vascular plants?
- lycophyta: club mosses
- sphenophyta: horsetails
- pterophyta: ferns
Are vascular plants gametophyte or sporophyte dominant?
sporophyte
Describe lycophyta
- club mosses
- strobili
- microphylls
- true roots
strobili
clusters containing spores
microphylls
leaflike structures; look like spirals on the stem
sphenophyta
- horsetails
- all species in genus equistum
- leaves grow in whorls
- silica in cell walls
pterophyta
- ferns
- leaves can grow to 30 m
- spores within sori
what is overtopping?
- new branches grow beyond others
- advantage for photosynthesis
- formed photosynthetic tissues
example of photosynthetic tissues
megaphyll
what did megaphyll aid with
increased photosynthetic surface area
define gymnosperm
“naked seed”
-ovule is not protected by an ovary, seeds not protected by fruit
list two innovations of seed plants
seeds and woody tissue
why was the evolution of woody tissue important?
- allowed secondary growth (horizontal/width)
- extra support allowed plants to get taller (light)
list three phyla of gymnosperms
- cycadophyta (300 species-atrium)
- ginkgophyta (only one living, ginkgo biloba)
- coniferophyta (700 species)
what is the difference between pollination and fertilization?
pollination: pollen grain lands near female gametophyte
fertilization: a pollen tube tunnels to megagametophyte
what are the three parts of a seed?
- seed coat
- food supply
- embryo
seed coat
develops from integument
food supply
female gametophyte
embryo
new diploid sporophyte generation
why was the evolution of seeds such an innovation?
- they are protected resting stages and can remain resting for years and germinate when conditions are favorable
- seed coat prevents the seed from drying out
- have adaptations for dispersal
define angiosperm
“covered seeds”, flowering plants
list the 6 synapomorphies of angiosperms
- flowers
- ovules and seeds enclosed in carpel
- pollen on a stigma
- double fertilization
- endosperm
- fruit
What term is used for grouped flowers?
inflorescence
what is the difference between a perfect and an imperfect flower?
perfect flower- have both mega and microsporangia
imperfect flower- have one or the other, not both
What are the advantages of perfect flowers?
flower can pass on genes in two different ways; can pollinate and be pollinated
What are the disadvantages of perfect flowers?
self fertilization
Describe double fertilization
- two sperm reach megagametophyte
- –1 fertilizes the egg and the embryo is formed
- –1 “fertilizes” central cell and forms triploid (3n) endosperm
Define endosperm
surrounding food source for the developing embryo
what is fruit? and how does it benefit plants?
fruit- developed ovary and seed
advantages- protects seeds, useful for dispersal (animals, wind/water)
