Section 26.2 (Exam 2) Flashcards
Key Adaptations Permitted Plants to Colonize Land
What did plants need to survive on land?
Water transport mechanisms
Physical support
Mechanisms to distribute gametes and progeny
A way to avoid desiccation
What are cuticles?
waxy coating that retards water loss (lipid-based)
What are stomata?
openings in stems and leaves that regulate gas exchange and water loss
What are gametangia?
organs that enclose gametes
One adaptation of land plants is a protective structure around the _________.
embryo
What is the function of thick spore walls?
preventing desiccation and decay
What adaptation of land plants can protect against UV radiation?
pigments
What benefit do land plants derive from association with fungi like mycorrhizae?
better nutrient uptake from the soil
Growing roots can contribute to the mechanical breakdown of ______.
soil
Organic material from dead plants contributes to ___________________.
soil formation
Acid secreted by ancient plants helped break down rock, which contributed to ___________________.
soil formation
Haploid gametes fuse to form a __________ via _____________.
zygote; fertilization
Alternation of generations occurs in ________________.
all land plants
Gametophytes produce ________________ by mitosis.
haploid gametes
After mitosis, the zygote ultimately becomes a ________________________.
diploid sporophyte
The diploid sporophyte produces ____________ by meiosis.
haploid spores
Spores germinate and divide by mitosis and produce _________________.
the haploid gametophyte
Multicellular diploid plant is the _____________.
sporophyte
Cells within the _____________, a specialized reproductive organ, undergo meiosis to produce haploid, unicellular spores.
sporangia
Spores develop into a multicellular haploid plant, the _________________.
gametophyte
Evolutionary trends show a _____________ of the gametophyte generation.
reduction
In non-vascular plants, the gametophyte is __________________________________ than the sporophyte. In plants that appeared later, this is reversed.
longer-lived and more self-sufficient
Non-vascular plants, also called bryophytes, transport water through ____________.
diffusion
Non-vascular plants, or bryophytes, have a thin __________ and live in moist environments.
cuticle
Non-vascular plants, or bryophytes, lack true ____________________.
leaves, stems, and roots.
What are non-vascular plants also known as?
Bryophytes
Sporophytes are always ____________ dependent on the gametophyte and are permanently attached; they produce spores in a ________________.
nutritionally; sporangium
Gametophytes are photosynthetic, the male and female gametes are produced in different structures called the ____________________________.
antheridia and archegonia
Sperm from the antheridia can only fertilize the egg within the archegonium in the presence of _______. This is only the case in plants without seeds, everything except for ________________________________.
water; gymnosperms and angiosperms
Spores germinate in the ________________, otherwise they remain dormant.
ideal conditions
Germinating spores of moss grow a bud. What does this bud grow into?
Gametophytes
What is protonema?
filamentous structure of a moss that contains chlorophyll (photosynthetic)
What is a rhizoid in bryophytes?
A root-like structure in bryophytes that helps anchor the plant to the substrate and absorb water
Some of these bryophytes have leafy gametophytes and are thalloid.
Liverworts
The ______________ of liverworts are only a few millimeters high.
sporophytes
What is a thalloid structure?
It is leaflike and lies flat on the ground.
In liverworts, a stalk raises the ___________ above ground level to allow spores to be dispersed.
sporangium
Liverworts reproduce ___________ by ________________ of the gametophyte
asexually; fragmentation
What are gemmae?
lens-shaped clumps of cells, sometimes in cup shapes. They are dispersed by raindrops and lead to growth of a new plant, like seeds.
Mosses have ________ which are important in water and gas exchange.
stomata
Stomata are present in mosses and other land plants except for _____________.
liverworts
Gametophytes of moss begin development as a __________.
protonema
Some mosses have specialized cells called _________, which die and form channels through which water can move. This is useful for mosses that grow too large for diffusion to be effective.
hydroids
Sphagnum moss likes to grow in ___________________.
cool, swampy places
Upper layers of moss can compress lower layers that are decomposing, which forms _____.
peat
How can peat be used?
it can be burned as fuel
The gametophytes of __________ are flat plates of cells.
hornworts
What do the green sporophytes of hornworts look like?
small horns
Cells of hornworts have a single, large ___________. Liverworts and mosses have many.
chloroplast
The hornwort sporophyte has a basal region capable of indefinite ________________.
cell division or growth
Hornworts have specialized internal cavities. _____________________ live in these cavities.
Symbiotic, nitrogen-fixing cyanobacteria (heterocysts)
In plants, the diploid and haploid stages of the life cycle both include ______________ individuals, and gametes are produced by _________.
multicellular; mitosis
