Plant Lineages and Evolutionary Innovations

4 major challenges that early land plants faced

desiccation, support, transport, reproduction

desiccation: how do you keep cells from ____

drying out

support: how do you stay upright without

water’s buoyancy

transport: how do you move water and nutrients without being ____

submerged in them

reproduction: how do you get gametes to meet without a ____

watery medium

earliest known life is ___ years old

3.5 billion

photosynthesis evolved ____ years ago

2.3-3.2 billion

_____ (most chemically inert biopolymer known) envolved 475 million years ago

sporopollenin

land plants desended from

charophyta algae

two structures for desiccation solution

cuticle and stomata

cuticle is a ____ layer on epidermis

waxy, impermeable

cuticle trade-off

blocks gas exchange

stomata is a plant mouth that can open and close through ____ to allow for ____

guard cells, gas exchange

support and transport solution

vascular tissue (xylen, pholeum, lignin)

____ is water-conducting cells

xylem

____ is food-conducting cells

phloem

____ is the woody part of wood

lignin

land plants inherited alternation of generations from ____ but modified it critically

algae

animals and some algae: meiosis produces _____ directly. no _____

gametes, free-living haploid generation

plants and many algae: meiosis produces ____, which develop into a _____

spores, free-living gametophyte generation

3 types of bryophytes

mosses, liverworts, hornworts

bryophyta are

mosses

marchantiophyta are

liverworts

anthocerotophyta are

hornworts

bryophytes are most found in ____ habitats

moist

bryophytes have a dominant ____ generation

gametophyte

bryophytes have no true (3)

leaves, roots, shoots

bryophytes are still ecologically important today for (3)

carbon sequestration, peat bogs, pioneer species

bryophytes cuticle present but

incomplete

bryophytes cuticle is ____, ____ not all species have it

thin, discontinuous

bryophytes cuticle:

important because most bryophytes absorb water through

entire surface of plant

bryophytes cuticle:

allows for _____, not inhibition

desiccation tolerance

bryophytes cuticle-stomata trade off:

cuticle solves desiccation but blocks

CO2 entry

bryophytes cuticle-stomata trade off:

stomata solves gas exchange but create ____ through which ____

openings, water escapes

bryophytes cuticle-stomata trade off:

the two innovations are there in direct tension — every stomatal opening that lets ____ in also lets ____ out

CO2, water vapor

____ plants manage this cuticle-stomata trade-off better but they don’t solve it

vascular

bryophytes have no ____ tissues

lignin-reinforced conducting

bryophytes have no lignin-reinforced conducting tissues:

no (2)

height, long distance water/nutrient transport

bryophytes have no lignin-reinforced conducting tissues:

_____ direct consequence

size constraint

bryophytes evolved ____ cells independently

conducting

bryophytes — hydroids (hadrom):

_____ conduction — analogous to ____

water, xylem

bryophytes — hydroids (hadrom):

no ____ therefore collapse under pressure and cannot support height

lignin-reinforced walls

bryophytes leptoids (leptom):

_____ conduction —- analogous to ____

nutrient, pholeom

bryophytes — leptoids (leptom):

less ____, found only in some mosses

efficient

in bryophytes, the ____ is the green plant you see. the ____ is small, dependent, attached

gametophyte, sporophyte

sporophyte = ____ generation

diploid (2n)

gametophyte = _____ generation

haploid (n)

_____ does all the metabolic work (photosynthesis, water absorption, embryo retention)

gametophyte

great ____ → _____ → go everywhere

colonizers, spores

poor ____ → gametophyte needs constant ____

competitors, moisture

bryophytes reproduction requires

water

bryophytes:

sperm are ____ and must swim to reach eggs

flagellated

bryophytes:

_____ only occurs when a film of water connects sperm to egg

fertilization

bryophytes:

limits sexual reproduction to ___ conditions, regardless of where spores land

wet

bryophytes:

no water film = no _____ = no ____

fertilization, sporophyte generation

bryophytes dominate _____ (boreal forests, tundra, and peatlands despite being primitive)

vast ecosystems

bryophytes:

_____ store more carbon than any other plant genus on earth

peat mosses (sphagnum)

bryophytes act as ____, colonizing bare rock and distrubed ground, building soil for ____

pioneer species, vascular plants

bryophytes regulate ____ in ecosystems (act as ____, slowly releasing wastr during dry periods)

water retention, sponges

5 types of ferns

club mosses, spike mosses, quillworts, true ferns, horsetails

fern characteristics:

____ tissue

true (3)

____ dominant

vascular

roots, shoots, leaves

sporophyte

_____ is the innovation that unlocks height

vascular tissue

seedless vascular — xylem:

____ cells

_____ reinforced

conduct ____ and ____

one direction (_____)

dead

lignin

water and inorganic minerals

up

seedless vascular — lignin:

rigid, _____ molecule embedded in ____

____ support

waterproof, cell wall

structural

seedless vascular — pholeom:

____ cells

conducts ____ from source to ____

living

nutrients, sink

seedless vascular — vascular tissue

plants can now compete vertically for ____, transport substances ___, and colonize ___ habutats

height, long distances, drier

bryophytes have ____, which are single-celled or filamentous ____ structures with no ____ tissue

rhizoids, anchoring, conducting

seedless vascular roots are fundamentally different (3)

multicellular, vascularized, metabolically active

seedless vascular — true roots:

____ the plant against gravity and wind

____ water and minerals across a massive ____

____ to vascular tissue (water enters roots and moves directly to xylem)

____ carbohydrates delivered from leaves via ____

anchor

absorb, surface area

connect

store, phloem

____ hold on. ___ hold on, absorb, transport, and store (a single structure solving four problems simultaneously)

rhizoids, roots

seedless vascular — true leaves maximize ___

photosynthetic surface

seedless vascular — true leaves

dedicated photosynthetic surface: maximizes _____

light capture

seedless vascular — true leaves

stomata concentrated on ____ surface: _____ localized

leaf, gas exchange

seedless vascular — true leaves

vascular supply delivers ____ in, carries ____ throughout

water, sugars

seedless vascular — true leaves

____ on leaf surface: controls ____ loss

cuticle, water

seedless vascular — two types of leaves

microphylls and megaphylls

seedless vascular — microphylls found in

lycophytes

seedless vascular — microphylls vascular supply

single unbranched vein

seedless vascular — microphylls origin

outgrowth of stem tissue

seedless vascular — microphylls surface area

small

seedless vascular — megaphylls found in

ferns and all higher plants

seedless vascular — megaphylls vascular supply

branching vascular network

seedless vascular — megaphylls origin

thought to be flattened branch systems

seedless vascular — megaphylls surface area

large

seedless vascular: the fern frond you see is the _____ — large vascularized dominant

sporophyte (2n)

seedless vascular is ____ independent

____ and produces ___ on its own

gametophyte, photosynthesizes, gametes

seedless vascular gametophyte is ____ lived

only survives long enough to support early ____

short, sporophyte

seedless vascular:

the ____ is now in charge but the ___ hasn’t been ____ yet

sporophyte, gametophyte, protected

similar to bryophytes, seedless vascular plants are still

water dependent

seedless vascular:

____ must grow in moist conditions for reproduction to occur

gametophyte

seedless vascular — water dependence

can grow tall and colonize drier habitats vegetatively but ____ pulls them back to wet environments every generation

sexual reproduction

seedless vascular — water dependence

_____ is still constrained by moisture availability during reproduction periods

distribution

gymnosperm means ____, seeds exposed on ____ + not enclosed in ____

naked seed, cone scales, fruit

pines, firs, spruces, redwoods (dominant boreal forests globally) are

conifers

palm-like, ancient lineage, mostly tropical are

cycads

single living species, ginkgo biloba, unchanged for 200 million years are

ginkgo

unusual group, some features convergent with angiosperms are

gnetophytes

gymnosperms dominated ____ ecosystems before angiosperms — still ecologically dominant in ___ and ___ climates

terrestrial, cold, dry

three parts of a seed

embryo, endosperm/nutrient tissue, seed coat

gymnosperm — embryo

the next ____, already developed and waiting

sporophyte