Lecture Exam #3 Flashcards
what are key adaptions for life on land?
seeds and pollen
what is common to all seed plants? (4) (RHOP)
1) reduced gametophytes
2) heterospory
3) ovules
4) pollen
the rule among seed plants
heterospory
what were the ancestors of seed plants likely?
homosporous
what were seed plants likely?
heterosporous
produces megaspores
megasporangia
what do megasporangia give rise to?
female gametophytes
produces microspores
microsporangia
what does microsporangia give rise to?
male gametophytes
what changed the course of plant evolution?
seeds
how did plants change the course of plant evolution?
by enabling their bearers to become dominant producers in most terrestrial ecosystems
when did seed plants originate?
360 million years ago
what does a seed consist of?
an embryo and nutrients surrounded by a protective coat
how does seeds disperse?
over long distances by wind or other means
what are the advantages of reduced gametophytes?
the gametophytes of seed plants develop within the walls of spores that are retained within tissues of the parent sporophyte
what does an ovule consist of?
1) a megaporangium
2) a megaspore
3) one or more protective integuements
how many integuments do angiosperm megaporangia usually have?
2
what do micropsores develop into and what do they contain?
pollen grains and they contain the male gametophytes
the transfer of pollen to the part of a seed plant containing the ovules
pollination
what does pollen elimante the need for and how can it be dispersed?
film of water and can be dispersed great distances by air or animals
what happens if a pollen grain germinates?
it gives rise to a pollen tube that discharges sperm into female gametophyte within the ovule
“naked seeds”
gymnosperms
what are gymnosperms exposed to?
sporphylls that form cones
where are angiosperm seeds found and what are they?
they are found in fruits which are matured ovules
what most gymnosperms and cone-bearing plants are called
confiers
what type of tree is the pine tree and what does it produce?
the sporophyte and produced sporangia in male and female cones
what do small cones produce and what do they contain?
microspores called pollen which contain a male gametophyte
what do the familiar larger cones contain and what do they produce?
they contain ovules and produce megaspores that develop into female gametophytes
how long does it take from cone production to mature seed?
nearly 3 years
evolutionary advantages of seeds (2) (SS)
1) a seed develops from the whole ovule
2) a seed is a sporophyte embryo, along with its food supply, packaged in a protective coat
advantages of seeds over spores
1) they may retain dormant for days to years, until conditions are favorable for germination
2) seeds have a supply of stored food
3) they may be transported long distances by wind or animals
3 key features of the gymnosperm (life of a pine) life cycle (3) (MDT)
1) minaturization of their gamteophytes
2) development of seeds from fertizlied ovules
3) the transfer of sperm to ovules by pollen
what does fossil evidence reveal about seed plants and the rise of gymnosperms
by the late deovonian period, some plants had begun to acquire some features that are also present in seed plants
what is an example of fossil evidence of the rise of gymnosperms?
archaeopteris was a hetersporous tree with a woody stem, but it did not bear all seeds
what did gymnosperms serve as for herbivourous dinousaurs?
food
what did recent fossil discoverie show about gymnosperms?
that they were pollinated by insects over 100 millions
when did angiosperms begin to replace gymnosperms?
near the end of the Mesozoic
4 phyla of gymnosperms (4) (CGGC)
1) cyadophyta (cyads)
2) ginkophyta
3) gnetophyta
4) confirerophya (pine, fir and redwood)
in the phylum cyadophyta what do inviduals have?
large cones and palmlike leaves
unlike most seed plants what does cyads have?
flagellated sperm
when did cyads thrive?
during the Mesozoic but most of the few surviving species are endangered
2 clades of living seed plants
1) gymnosperms
2) angiosperms
when did gymnosperms appear early in the fossil record?
about 305 million years ago and dominated Mesozoic terrestrial ecosystems
what were better suited than nonvascular plants to drier conditions?
gymnosperms
what now dominates more terrsetrial ecosystems?
angiosperms
despite angiosperms dominating more terrestrial ecosystems now what still dominates in some regions including northern latitutudes?
conifers
example of the phylum cyadophyta
cycas revoluta
what does the phylum ginkophyta consist of?
a single living species, Ginko biloba
what does the phylum ginkophyta have like cyads?
flagellated sperm
what does the phylum ginkophyta have a high tolerance for?
air pollution and is a popular ornamental tree
what is the largest of the gymnosperm phyla?
phylum confierophyta
what are most confiers and what can they do?
evergreens and they can carry out photosynthesis year round
what do the reproductive adaptions of angiosperms include?
flowers and fruit
what are the most widespread and diverse plants?
angiosperms
3 genera of phylum gnetophyta (GEW)
1) gnetum
2) ephedra
3) welwitschia
what do species of the phylum gnetophyta vary in and what are some of them?
appearance, and some are tropical whereas others live in deserts
what are all angiosperms classified in?
a single phylum, Anthophyta (from the Greek anthos for flower)
an angiosperm structure specialized for sexual reproduction
flower
what were many flowers pollinated by?
insects or animals, while some of wind-pollinated
four types of modified leaves called floral organs (SPSC)
1) sepals
2) petals
3) stamens
4) carpels
consists of a stalk called a filament with a sac called an anther
stamen
consists of an ovary at the base and a style leading up to the stigmas
carpel
flowers that have all four organs
complete flowers
flowers lacking one or more organs
incomplete flowers
what type of symmetry may flowers have?
radial or bilateral
a flower where any imaginary line through the central axis divides the flower into two equal parts
radial symmetry
a flower that can be divided into two equal parts by a single imaginary line
bilateral symmetry
do most species have flowers with both functional stamen and carpels?
yes but some species occur on separate flowers
where may stamens be on a plant?
they may be on the same plants as those with carpels or they may occur on different plants
formed when the ovary wall thickens in a plant
fruits
what do fruits do for a plant?
protect seeds and aid in their dispersal
what can mature fruits be?
fleshy (orange,strawberry) or dry (nuts)
what do various fruit adaptions help with?
dispersal of seeds
ways seeds can be carried (3) (WWA)
1) wind
2) water
3) animals to new locations
what is the flower of the sporophyte composed of?
both male and female structures
where are male gametophytes contained within and what are they produced by?
pollen grains and produced by microsprangia of anthers
where does the female gametophyte or embryo sac develop within and where is it contained?
an ovule and is contained within an ovary at the base of the stigma
what do most flowers have mechanisms to ensure?
cross-pollination between flowers from different plants of the same species
during the lifecycle of an angiosperm, once the pollen grain has landed on a stigma what happens?
it germinates and the pollen tube of the male gametophyte grows down to the ovary
where is the ovule entered by?
a spore called the micropyle
occurs when the pollen tube discharges two sperm into the female gametophyyte within an ovule
double fertilization
during double fertization while one sperm fertizlies the egg what does the other one do?
combine with two nuclei in the central of the female gametophyte and initiate the development of food-storing endosperm
what does the triploid endosperm nourish?
the developing embryo
within a seed, it’s what the embryo consists of a root and a two seed leaves (becomes leaves)
cotyledons
what did Darwin call the origin of angiosperms?
“abominable mystery”
what is progress of angiosperms being made through?
fossils and phylogenic analysis
have the mystery of the sudden appearanceo f angiosperms been resolved?
no
when did the ancestors of angiosperms and gymnosperms diverge?
about 305 million years ago
what may angiosperms be closely related to?
bennetitales (extinct seed plants with flowerlike structures)
what likley descended from two of the most ancient angiosperm lineages?
amborlla and water lilliess
what affects the movement of pollinators and reduces gene flow in diverging population?
bilateral symmetry
what may plant with bilateral symmetry have increased rates of?
speciation
how can the hypothesis be tested of plants with bilateral symmetry having increased rates of speciation?
by comparing number of species in closely related “bilateral” and “radial” clades
based on the features of ancestral and basal taxa including Amborella,what were early angiosperms likely?
small-flowered shrubs with simple water-conducting cells
what influences evolution?
animals influence the evolution of plants and vice versa
what is an example of animals influencing plant evolution?
animal herbivory selects for plants defenses
what is an example of plants and animals influencing evolution?
interactions between pollinators and flowering plants select for mutually beneficial adaptions
how many species do angiosperms comprise?
more than 250,000 living species
what 2 groups were angiosperms previously divided into?(MD)
1) monocots (one cotyledon)
2) dicots (two dicots)
what does DNA suggest about angiosperms’s diversity?
that dicots are paraphyletic
what does the clade eudicot (“true dicots”) include?
most dicots
what do basal angiosperms include and what do they belong to?
flowering plants belonging to the oldest lineages
what do magnolilds share traits with?
basal angiosperms but evolved later
what consititutes basal angiosperms?
3 small lineages
what do the 3 small lineages that constitutes basal angiosperms include? (4) (ATWS)
1) Amborella
2) trichopoda
3) water lilies
4) star anise
what do magnolids include? (3) (MLB)
1) magnolias
2) laurels
3) black pepper plants
what are magnolids more closely related to than basal angiosperms?
monocots and eudictos
how many angiosperm species are monocots?
more than one-quarter
what are the largest groups of monocots (3) (OGP)
1) orchids
2) grasses
3) palms
how many angiosperm species are eudictos?
more than two-thirds
what do eudicots include? (2) (LE)
1) large legume family
2) economically important rose family
what does human welfare depend on?
seed plants
what are seed plants the key sources of? (4) (FFWM)
1) food
2) fuel
3) wood products
4) medicine
what makes the preservation plant diversity very critical?
one reliance on seed plants
what does most of our food come from?
angiosperms
what are 6 crops that yield 80% of the calories consumed by humans (WRMPCS)
1) wheat
2) rice
3) maize
4) potatoes
5) cassava
6) sweet potatoes
what are modern crops the product of?
relatively recent genetic change
what are relatively recent genetic change resulting from?
artificial selection
what do many seed plants provide?
wood
what type of seed plants are used in meidcines?
secondary compounds of seed plants
what is something that causes extinction to many plants species and is a threat to plant diversity?
destruction of habitat
how many plants are cleared each year in the tropics?
55,000km2
at the rate of clearing of plants in the tropics what will happen to the remaining tropical forests?
it will be eliminated in 200 years
what does loss of forests do?
reduces the absorption of atmospheric CO2
when does reducing the absorption of atmospheric CO2 occur?
during photosynthesis
what is loss of plant habitat usually accompanied by?
loss of animal species that plants support
at the current rate of habitat loss how much of Earth’s species will become extinct in the next 100-200 years?
50%
what may tropical rain forest contain?
undiscovered medicinal c ompounds
what type of gametophyte sporophyte relationship do mosses and other non vascular plants have?
dominant gametophyte and the sporophyte is reduced and dependent on gametophyte for nutrition.
wha type of gametophyte sporophyte relationship do ferns and other seedless vascular plants have?
reduced independent (photosynethetic and free-living) gametophyte and dominant sporophyte
what type of gametophyte sporophyte relationshp do seed plants have (angiosperms and gymnosperms)?
reduced (usually microscopic) dependent on surrounding sporophyte for nutrition gametophyte and dominant sporophyte
a structure that develops within the ovary of a seed of a plant and contains the female gametophyte
ovule
in flowers, the portion of the carpel in which the egg-containing ovules develop.
ovary
layer of sporphyte tissue that contributes to the structure ovule of a seed plant
integument
characteristics of angiosperms that show their reproductive adaptions (2) (TT)
1) they are seed plants with reproductive structures called flowers and fruits
2) they are the most widespread and diverse of all the plants
what is the function of the stamen?
produces pollen
what is the function of the carpel?
receives pollen
a modified leaf of a flowering plant. often colorful parts of a flower.
petal
what is the function of petals?
to attract insects and other pollinators
part of a carpel (4) (SOOS)
1) style
2) ovary
3) ovule
4) stigma
what is the function of the modified leaf of angiosperms, sepals?
it encloses and protects the flower bud before it opens
a tough outer covering of a seed, formed from the outer coat of an ovule
seed coat
what is the function of the seed coat?
in flowering plant, it encloses and protects the embryo and endosperm
in an angiosperm embryo, the embryonic axis below the point of attachement of the cotyledon and above the radicle
hepocotyl
an embryonic root of a plant
radicle
in an angiosperm embryo, the embryonic axis above the point of attachement of the cotyledons and below the first pair of miniature leaves
epicotyl
in angiosperms, a nutrient-rich tissue formed by the untion of a sperm with 2 polar nuclei during double fertilization.
endosperm
what is the function of the endosperm?
it provides nourishment to the devleoping embryo in angiosperm seeds
a seed leaf of an angiosperm embryo. some species have one and others have 2
cotyledon
a fruit derived from a single carpel or several fused carpels
simple fruit
a fruit derived from a single flower that has more than one carpel
aggregate fruit
a fruit derived from an entire inflorescence
multiple fruit
a fruit, or assemblage of fruits, in which the fleshy parts are derived largely or entirely from tissues other than the ovary
accessory fruit
how is the plant cycle modified in angiosperms?
the sporophyte is the dominant generation. the gamertophytes are the most reduced of all plants in angiosperms
3 traits of angiosperm life cycle (3) (FFF)
1) flowers
2) fertlization
3) fruits
what is the fate of the ovule after fertilization?
it develops into a seed
what is the fate of the ovary after fertilization?
it develops into a fruit
what is the fat of the endosperm after fertilization?
it become solid
advatages of reproducing sexually (3) (MCA)
1) more genetic variation
2) children different than parents
3) able to produce more offspring because of mate
disadvantages of reproducing sexually (3) (SLT)
1) slower reproduction rate
2) less realizable reproduction
3) takes time and energy to find mate
advantages of reproducing asexually (3) (CDC)
1) can reproduce twice as many
2) does not require fertilization
3 can quickly colonize
disadvantages of reproducing asexually (2) (RV)
1) reproduction based on amount of food
2) very little variation which may cause extinction
what do we mean by plant diversity is a non-renewable resource?
because extinction is irreversible. it decreases the total diversity of plants many which could have had important benefits to humans
what is the function of the hepocotyl?
it pushes the cotyledons above the ground to develop.
what is the function of the radicle?
it allows the seed to suck up water and send out its leaves so it can start photosynthesizing
what is the function of the epicotyl?
it gives rise to the stem and leaves
what is the function of the cotyledon?
it provides nutrients/food for the germinating plant to survive in the seed. forms the first green leaves
