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166 Cards in this Set

  • Front
  • Back
___, which led to the gymnosperms and angiosperms, the plants that dominate most modern landscapes
Seed plants
what terrestrial adaptations contributed to the success of seed plants?
the existance of the seed and the reduction of the gametophyte generation, heterospory, ovules, and pollen
the Bryophyte life cycles are dominated by what generation?
gametophyte generation
seedless vascular plants have a ___ dominated life cycle.
gametophyte reduction continued in the lineage of vascular plants that led to ___.
seed plants
Seedless vascular plants have tiny ___ that are visiable to the human eye.
The gametophytes of seed plants are microscopically small and develop from ___ retained within the ___ of the parental ___.
The gametophytes of ___ obtain nutrients from their parents, while the free-living gametophytes of ___
must fend for themselves.
seed plants,
seedless vascular plants
In seed plants ____ and ___ are protected from many environmental stresses, including drought and UV radiation.
female gametophyte and the young sporophyte embryo
Nearly all seedless plants are ___ producing a single kind of spore that forms a ___.
hermaphroditic gametophyte
Seed plants likely had what kind of ancestors?
All seed plants are ___ producing two different types of sporangia that produce two types of spores.
Megasporangia produce ___ which give rise to ___.
female (egg-containing) gametophytes
Microsporangia produce ____ which give rise to ___.
male (sperm-containing) gametophytes
seed plants are unique in retaining their megaspores within the ___.
parent sporophyte or ovules
Layers of sporophyte tissue, called ____, which envelop and protect the megasporangium
Gymnosperm megaspores are surrounded by how many integument?
Angiosperm megaspores are surrounded by how many integuments?
An ovule consists of what 3 things?
the megasporangium, megaspores, and integuments
A female gametophyte develops from ___ and produces ____.
a megaspore,
one or more egg cells
The microspores develop into ____ that are released from the ____.
pollen grains,
Pollen grains are covered with a tough coat containing ____.
How are pollen grains transported?
by wind or animals
The transfer of pollen to the vicinity of the ovule is called
The pollen grain germinates and grows as a pollen tube into the ovule, where it delivers ____ into the female gametophyte.
one or two sperm
Bryophytes and seedless vascular plants have ____ that swim a few centimeters through ____ to reach the ____.
flagellated sperm cells,
a film of water,
The sperm of seed plants lack flagella and do not require a film of water, as they rely on _____
the pollen tube
The evolution of pollen contributed to the success and diversity ____.
of seed plants
When a sperm fertilizes an egg of a seed plant, the zygote forms and develops into a _____.
sporophyte embryo
The ovule develops into a seed, consisting of what?
the embryo and its food supply within a protective coat
The evolution of the seed enabled plants to _____________.
resist harsh environments and disperse offspring more widely
For bryophytes and seedless vascular plants, single-celled spores are the only ________.
protective stage in the life cycle
True of False?

Moss spores can survive even if the local environment is too cold, too hot, or too dry for the moss plants themselves to survive
Because of their ________
the spores themselves can be dispersed in a dormant state to a new area
tiny size
What were the main way that plants spread over Earth for the first 100 million years of life on land.
The seed represents a different solution to resisting harsh environments and dispersing offspring, what is a more complex resistant technique?
a multicellular seed compared to a single seed spore.
Under favorable conditions a seed does what?
it germinates and the sporophyte embryo emerges as a seedling
• The ovules and seeds of gymnosperms (“naked seeds”) develop on the surfaces of modified leaves that usually form ____.
The most familiar gymnosperms are the
Define: conifers
cone-bearing trees such as pine, fir, and redwood
what are the four phyla of extant gymnosperms?
Cycadophyta, Ginkgophyta, Gnetophyta, and Coniferophyta
What phylum consists of only a single extant species, Ginkgo biloba
This popular ornamental species has fanlike leaves that turn gold before they fall off in the autumn. What phylum is it?
Why do landscapers usually plant only male trees?
because the coats of seeds produced by female plants produce a repulsive odor as they decay
What phylum have large cones and palmlike leaves?
Cycadophyta or Cycads
How many Cycads exist today?
Cycads flourished in what era? It was known as “Age of Cycads.”
Mesozoic era
What Phylum consists of three very different genera:
Weltwitschia plants,Gentum species, Ephedra (Mormon tea)
describe Weltwitschia plants.
They are from deserts in southwestern Africa, have straplike leaves that are among the largest known leaves.
describe Gentum.
this species are tropical trees or vines
Describe Ephedra
It is a shrub of the American deserts
The conifers belong to the largest gymnosperm phylum _____.
the phylum Coniferophyta
The term conifer comes from the ___________________________.
the cone, which is a cluster of scalelike sporophylls.
Although there are only about 600 species of conifers ____________________.
a few species dominate vast forested regions in the Northern Hemisphere where the growing season is short
What do Conifers include?
pines, firs, spruces, larches, yews, junipers, cedars, cypresses, and redwoods
Most conifers are evergreen, explain evergreen.
Evergreen means they retain their leaves and photosynthesize throughout the year
redwood and tamarack, are deciduous, explain deciduous.
they drop their leaves in autumn.
The needle-shaped leaves of some conifers, such as pines and firs, are _____________.
adapted for dry conditions
what reduces water loss in some conifers?
A thick cuticle covering the leaf and the placement of stomata in pits
Much of our lumber and paper comes from _______.
the wood (actually xylem tissue) of conifers
what trees are amongst the largest and oldest organisms of Earth?
The gymnosperms probably descended from ____. Why?
progymnosperms, a group of plants that were heterosporous but lacked seeds
The first seed plants to appear in the fossil record were gymnosperms dating from ____.
360 million years ago
Early gymnosperms lived in Carboniferous ecosystems dominated by
seedless vascular plants
• The flora and fauna of Earth changed dramatically during the formation of the supercontinent Pangaea in the Permian. What happened?
Climatic conditions became warmer and drier, favoring the spread of gymnosperms
Amphibians decreased in diversity and were replaced by _____ which were better adapted to dry conditions.
The change in organisms was so dramatic that _______________.
their is a boundary between the Paleozoic (“old life”) and Mesozoic (“new life”) eras
The terrestrial animals of the Mesozoic, including ____ and were supported by ____.
dinosaurs, vegetation
The life cycle of a pine illustrates what three key adaptations to terrestrial life in seed plants?
1. Increasing dominance of the sporophyte.
2. The advent of the seed as a resistant, dispersal stage in the life cycle.
3. The evolution of pollen as an airborne agent bringing gametes together.
The pine tree is the ____.
The pine tree does what?
It produces its sporangia on scalelike sporophylls that are packed densely on cones
Conifers are ___.
Male and female gametophytes develop from different types of spores that are produced from ____ and ____. Most pine species produce ____ types of cones.
small pollen cones, large ovulate cones, both
A pollen cone contains hundreds of ____ located on ____.
Each cone produces microspore mother cells that undergo meiosis to produce ____
haploid microspores.
Each microspore develops into a pollen grain containing _____.
a male gametophyte
A larger ovulate cone consists of many scales, which contain ____.
two ovules
Ovulate cones produce megaspore mother cells that undergo meiosis and develope into ____.
a megaspore
Surviving megaspores develop into ___ and remain in the ____.
female gametophytes,
the sporangia
Two or three archegonia, each with an egg, develop within ____.
the gametophyte
During pollination, what occurs?
windblown pollen falls on the ovulate cone and grows into the ovule through the micropyle.
The pine embryo, the new sporophyte, has
a rudimentary root and several embryonic leaves
The female gametophyte does what for the embryo?
surrounds and nourishes
The ovule develops into a pine seed, which consists of what?
an embryo (new sporophyte), its food supply (derived from gametophyte tissue), and a seed coat derived from the integuments of the parent tree (parent sporophyte)
The scales of ovulate cone separate and the seeds are typically dispersed by what?
the wind
A seed that lands in a habitable place germinates, and its embryo emerges as a ____ ____.
pine seedling
Angiosperms, commonly known as ___ are vascular plants, and produce ____ and ____.
flowering plants,
flowers and fruits.
All angiosperms are placed in a single phylum _____.
what angiosperm structure specialized for sexual reproduction?
the flower
what transfers pollen from one flower to female sex organs of another?
insects and other animals
Some species that occur in dense populations, like grasses are spread how?
by wind
A flower is a specialized shoot with up to four circles of modified leaves, what are they?
sepals, petals, stamens, and carpals
describe the sepals.
at the base of the flower are modified leaves that are usually green and enclose the flower before it opens
describe the petals
lie inside the ring of sepals and are colored according to how they are spread (by wind or animal).
Sepals and petals are sterile floral parts, not directly involved in what process?
the reproduction cycle.
describe Stamens
the male reproductive organs, are sporophylls that produce microspores that will give rise to pollen grains containing male gametophytes
A stamen consists of what?
a stalk (the filament) and a terminal sac (the anther) where pollen is produced.
Describe Carpals
female sporophylls that produce megaspores and their products, female gametophytes
At the tip of the carpal is a ___________.
sticky stigma that receives pollen
A style leads to ______.
the ovary, which is at the base of the carpal
Ovules are protected within ____.
the ovary
A fruit usually consists of what?
a mature ovary
As seeds develop from ovules after fertilization, what happens?
the wall of the ovary thickens to form the fruit
Fruits protect dormant seeds and
aid in their dispersal
The fruit develops after pollination does what?
triggers hormonal changes that cause ovarian growth
The wall of the ovary becomes the pericarp, explain pericarp.
the thickened wall of the fruit
when a fruit developes what happens to the remainer of the flower?
The other parts of the flower wither away in many plants
What if their is no fruit being produced, what happens to the flower?
the entire flower withers and falls away.
Mature fruits can be ____ or ____.
fleshy or dry
Oranges and grapes are ___ and have ____ pericarp
fleshy fruits,
one or more
beans and grains are ____.
dry fruits
how are Fruits classified?
according to whether they develop from a single ovary, from multiple ovaries, or from more than one flower.
By selectively breeding plants, humans have capitalized on _______.
production of edible fruits
Fruits are adapted to ___ ___.
disperse seeds
Winged seeds may function as __________.
kites or propellers to assist wind dispersal
Coconuts are specialized for __________.
water dispersal
All angiosperms are _________.
The immature male gametophytes are contained within _____.
pollen grains
pollen grains develope within ____.
the anthers of stamens.
Each pollen grain has two
haploid cells
a generative cell that divides to form ___ ____.
two sperm
a tube cell that produces a ____.
pollen tube
The ovule, which develops in the ovary, contains __________.
the female gametophyte, also known as the embryo sac
The embryo sac consists of only a few cells, one of which is ______.
the egg
The life cycle of an angiosperm begins with the formation of ________
a mature flower on a sporophyte plant and culminates in a germinating seed.
List the four steps describing the life cycle of an angiosperm.
1. Anthers contain microsporangia, containing microspore mother cells that produce microspores by meiosis.
2. Microspores form pollen grains, which are immature male gametophytes.
3. In the ovule, the megaspore mother cell produces four megaspores by meiosis.
 One megaspore survives and forms a female gametophyte, or embryo sac.
4. The pollen is released from the anther and carried to the sticky stigma of the carpel.
 Most flowers have mechanisms to ensure cross-pollination.
5. The pollen grain germinates and is now a mature male gametophyte.
 The pollen tube grows down within the style.
 After reaching the ovary, the pollen tube penetrates the micropyle, a pore in the integuments of the ovule.
 Two sperm are discharged into the female gametophyte.
 One fertilizes the egg to form a diploid zygote.
 The other fuses with two polar nuclei in the large central cell of the embryo sac to form the triploid endosperm nucleus.
 Double fertilization is unique to angiosperms.
6. The zygote develops into an embryo that is packaged with food into the seed.
 The embryo has a rudimentary root and one or two seed leaves, or cotyledons.
7. When a seed germinates, the embryo develops into a mature sporophyte.
Monocots store most of the food for the developing embryo as _____ which develops as a triploid tissue in the center of the embryo sac.
Beans and many dicots transfer most of the nutrients from the endosperm to the developing ____
One hypothesis for the function of double fertilization is ______________________.
that it synchronizes the development of food storage in the seed with development of the embryo.
Double fertilization may prevent flowers from _________.
squandering nutrients on infertile ovules
• Another type of double fertilization, in which two embryos are formed, has evolved independently in ________________.
gymnosperms of the phylum Gnetophyta
The seed in an angiosperm consists of ______________.
the embryo, endosperm, remnants of the sporangium, and a seed coat derived from the integuments
As the ovules (in Angiosperms) develop into seeds, the ovary _____________.
develops into a fruit
During germination, the seed coat (of an angiosperm) ruptures
and the embryo emerges as a seedling
It initially uses the food stored in the ____ and ____
to support development
endosperm and cotyledons
The oldest angiosperm fossils are about _________ years old.
140 million
These fossils display both ______ and ___________.
derived and primitive traits
A. sinensis has anthers and seeds inside closed _______ but lacks petals and sepals.
This species may be a “proto-angiosperm,” suggesting that the ancestors of flowering plants were ______ rather than woody.
It was found of angiosperms along with fish fossils and may be ______.
The “mostly male” hypothesis proposes that the ancestor of angiosperms had _____________ and that, as a result of a mutation, ovules developed on some microsporophylls, which evolved into carpels.
separate male and female structures
Flower-development genes are usually related to __________
pollen-producing genes
Certain mutations cause angiosperms to grow ovules on sepals and petals, demonstrating that __________.
the position of ovules can change
Angiosperms have diversified into more than ________ species that dominate most terrestrial ecosystems.
Until the late 1990s, flowering plants were divided into ______ and _____ on the basis of number of cotyledons or seed leaves.
The majority of plants traditionally called “dicots” form a clade now known as _____.
Three of these lineages are called ______ _____ because they include the oldest known lineages of flowering plants.
basal angiosperms
Amborella is a basal angiosperm that lacks _____________.
vessels that are found in more derived angiosperms
Another lineage of angiosperms is ____.
These angiosperms share primitive traits such as ____________.
spiral arrangement of floral parts with the basal angiosperms
One quarter of angiosperms are ______.
Monocot traits include _____________________________.
single cotyledons, parallel venation, scattered vascular bundles, fibrous root systems, pollen grains with a single opening, and floral parts in multiples of three
More than two-thirds of angiosperms are _____.
Eudicot traits include _________________.
two cotyledons, netlike venation, vascular bundles arranged as a ring, a taproot, pollen grains with three openings, and floral parts in multiples of four or five
Ever since they colonized the land, animals have influenced _______ and _______.
the evolution of terrestrial plants,
vice versa.
Plants and animals have been important __________.
selective agents on one another
Natural selection favored plants that kept their spores and gametophytes _____________.
above the ground, rather than dropping them within the reach of hungry ground animals
Some herbivores were beneficial to plants by __________.
dispersing their pollen and seeds
Natural selection reinforced these interactions when they improved _____________.
the reproductive success of both partners
Pollinator-plant relationships are partly responsible for increased ______________.
diversity of angiosperms and animals
The expansion of grasslands over the past 65 million years has __________.
increased the diversity of grazing animals such as horses
The shift from forests to grasslands in Africa between 10 and 2 million year ago was crucial to _____________.
hominid evolution
How do we depend on plants?
we depend on photosynthetic organisms for food production and oxygen release
We rely on seed plants for food, fuel, wood, and medicine
How did wild plants change so dramatically so quickly?
The answer is likely a combination of deliberate and unconscious selection for plants with desirable traits, such as large fruits and lack of toxins.
Gymnosperms and angiosperms are sources of wood, which is absent in all living seedless plants and ________________.
consists of an accumulation of tough-walled xylem cells
Although plants are a renewal resource _____ ____ is not.
plant diversity