GYMNOSPERMS & ANGIOSPERMS Flashcards
(99 cards)
1
Q
The vast majority of modern plants produce __ and include about __ species of
gymnosperms and almost __ species of angiosperms, so it is no wonder that seeds are so
familiar—particularly those of flowering plants
A
seeds
760
250,000
2
Q
gymnosperm seeds form on the __ or __ and are “exposed” in the sense that they are not completely enclosed within a fruit
A
surface of leaves
branches of cones
3
Q
gymnosperm seeds result from a __ of sperm and egg
A
single fertilization
4
Q
in gymnosperm seeds, the developing embryo is being nourished by the __
A
megagametophyte tissue
5
Q
angiosperm seeds result from a __ of sperm with egg and with __ of the megagametophyte (female gametophyte)
A
double fertilization
two nuclei
6
Q
in angiosperm seeds, the nourishment is provided by __
A
endosperm
7
Q
structure in angiosperm seeds - formed by the union of a sperm with two nuclei of the megagametophyte
A
endosperm
8
Q
for the plants that produce them, seeds provide the __ between generations—the future and the past
A
sexual biological link
9
Q
to be successful in an evolutionary sense, a plant must transfer its __ to the next generation
A
genes
10
Q
the evolution of the seed, an __ combined with a food supply and surrounded by a __, allowed plants to be much more successful on land
A
embryonic plant
protective seed coat
11
Q
the __ of seeds enables seed plants to survive extended periods of cold winter or drought
A
dormant state
12
Q
the __ serves as a barrier against bacterial or fungal decay
A
seed coat
13
Q
a __ produced by the microgametophyte (male gametophyte) delivers sperm to the egg, making fertilization possible without the presence of water
A
hollow pollen tube
14
Q
accordingly, the vast majority of seed plants have non-flagellated sperm
➢ the exceptions are a few gymnosperms, the __ and __
A
cycads
Ginkgo biloba
15
Q
the evolution of seeds is closely tied to the evolution of __ and sporangia on __
A
sporophylls
sporangia
16
Q
evolution of the seed
before the development of the large vascularized leaves known as __, sporophytes bore sporangia at the end of leafless branches known as __
A
megaphylls
telomes
17
Q
evolution of seed
the association of sporangia with leaves began during the __ period (409 to 363 million years ago) and continued through the evolution of the sporophytes of seedless vascular plants, gymnosperms, and finally angiosperms
A
Devonian
18
Q
evolution of seed
most of the intermediate forms of plants are extinct, but
two key precursors to the emergence of seeds were __ and __
A
heterospory
endosporic development
19
Q
evolution of seed
the original vascular land plants were probably __, with one type of spore produced by one type of sporangium
A
homosporous
20
Q
all seed plants are __, producing two types of spores,
__ and __, in two different types of sporangia, microsporangia and megasporangia
A
heterosporous
microspores
megaspores
21
Q
in most seedless plants, both extinct and living, spores germinate to produce gametophytes outside the confines of the spore wall, known as __
A
exosporic development
22
Q
the gametophytes of seed plants develop __, growing
inside the spore, a process also evident in a few seedless vascular plants, including Selaginella
A
endosporically
23
Q
the selective advantage of __ may be that it protects the developing gametophyte from desiccation while supplying nutrition and water
A
endosporic development
24
Q
The term gymnosperm is derived from the Greek gymnos, “__”, and sperma, “__”. This term has no taxonomic status, however, but rather is a descriptive of a heterogenous group of plants characterized by the production of naked seeds.
A
naked
seed
25
Estimates from fossil records indicate that gymnosperms must have evolved approximately 300 million years ago from non-seed-producing ancestors of the extinct division __, which were fern-like in appearance.
Progymnospermatophyta
26
_- is an adaptation of great significance for the survival and dispersal of plants. In fact, this was part of the competitive advantage that allowed the gymnosperms to supersede the other vascular plants as the dominant type of vegetation on land.
Seed production
27
although __ reproduction is found in a few species of gymnosperms, __ reproduction is predominant most gymnosperms
asexual
sexual
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gymnosperms, particularly __ are wind-pollinated
conifers
29
in some gymnosperm species, __ and _- are on separate plants
- pines and many other conifer species have both types of cones (strobili) on each plant
pollen cones
ovulate cones
30
gymnosperms
also known as female cones or seed cones, usually occur on higher branches
ovulate cones
31
gymnosperms
also known as male cones, typically occur on lower branches
pollen cones
32
gymnosperms
this arrangement promotes cross-pollination, because the windblown pollen is not usually distributed from the bottom to the top of the same tree
pollen cones
33
the transfer of
pollen from one plant to another
cros-pollination
34
ovulate cones in conifers are typically more complex than pollen cones
true
35
pollen cones in conifers are sometimes called __ because each cone consists of __ microsporophylls attached directly to a central axis
➢ each microsporophyll, known more commonly as a __, has two pollen-containing microsporangia on its lower surface
simple cones
spirally arranged
scale
36
the complex ovulate cones that are characteristic of pine and most other conifers are sometimes __ can enter through a small opening in the integument called a __ (Greek pyle, "gate").
grains
micropyle
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pine life cycle
unlike an antheridium, which contains many single-celled sperm, each __ contains several hundred microsporocytes, also known as __
microsporangium
microspore mother cells
38
pine life cycle
(1) each microsporocyte undergoes __ to produce four haploid microspores
▪ each microspore then gives rise to a __, a pollen grain
with four cells, that develops endosporically
meiosis
microgametophyte
39
pine life cycle
(2)
➢ two of the cells, known as __, have no known function
➢ a third cell is called the __ because it will give rise to a sterile stalk cell as well as to what is known as a body cell, which eventually produces two sperm
➢ the fourth cell is called the __ because it will produce the pollen tube, which is a device that facilitates delivery of sperm to the egg without water
prothallial cells
generative cell
tube cell
40
pine life cycle
(3) each pollen grain has two air sacs that function as "_-"
wings
41
pine life cycle
(4) pollen lands on drops of fluid produced by each megasporangium (nucellus) on each ovulate scale
(5) as the pollination droplet evaporates, the pollen is brought through the micropyle into contact with the megasporangium, where it __
(6) often, more than one pollen grain germinates in each megasporangium
(7) germination stimulates the development of the __
(8) about a month after pollination, the __, also known as a megaspore mother cell, divides by meiosis to produce four megaspores
(9) usually, only the megaspore farthest from the micropyle develops into the megagametophyte, while the other three megaspores abort
(10) when the megagametophyte nears maturity, which takes about a year in pines, typically _ archegonia form near the micropyle
germinates
megagametophyte
megasporocyte
2-5
42
the production of archegonia, each of which contains a single egg, is characteristic of most gymnosperms, including __, __, __, and __
conifer
cycads
Ginkgo biloba
Ephedra
43
pine life cycle
are a more primitive feature, which gymnosperms share with seedless plants
archegonia
44
in angiosperms and a few gymnosperms, __ and __, the mega-gametophytes do not produce archegonia
Welwitschia
Gnetum
45
pine life cycle
since there are often multiple pollen tubes, multiple archegonia are fertilized and more than one embryo initially develop, a phenomenon known as __
polyembryony
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pine life cycle
the __ is uncurved and has many cotyledons
pine embryo
47
pine life cycle
an __ becomes quite woody as it matures
ovulate pinecone
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some pines, such as the __ require intense heat for the seeds to be released
lodgepole pine (Pinus contorta),
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pine seeds are __, which aids in their transport by the wind
winged
50
(4) divisions of gymnosperms
D. Pinophyta (Conifers)
D. Cycadophyta (Cycads)
D. Ginkgophyta (Maidenhair Tree)
D. Gnetophyta (Gnetophytes)
51
division of gymnosperms
* the most familiar and most abundant gymnosperms, are particularly found in the temperate regions of the world
* consists of about 50 genera of trees with approximately 550 species
* includes the world’s tallest and largest plants
D. Pinophyta (Conifers)
52
tallest species of D. Pinophyta, grows up to 112.34 m (386.6 ft)
redwoods (Sequoia sempevirens)
53
the most massive species in D. Pinophyta, measuring 31 m (101.7 ft) in maximum circumference and is estimated to weigh 6,028 metric tons
▪ contains enough wood to build more than 100 3-bedroom houses
sequoia (Sequoiadendron giganteum), commonly
called the General Sherman tree
54
conifer wood is called __ because it cuts and nails easily
softwood
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__ have no fibers and has thinner cell walls than angiosperm wood described as hardwood
softwoods
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D. Pinophyta
produce __, which moves through the plant in resin ducts and helps protect the tress from attack of disease-casing organisms and herbivores
resin
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D. Pinophyta
often the dominant species in high elevation because they can tolerate cold weather and dry winds (characteristics)
o lack of vessel elements prevents permanent disruption of water flow by freezing
o needle-like leaves expose less surface to the air and are therefore less susceptible to damage by freezing or by dry winds
o the stomata are recessed to reduce loss of water
o beneath the epidermis is a thick layer of hypodermis preventing water loss
58
D. Pinophyta
leaves are simple and are borne singly or in cluster called _-
o leaves at the top of tall trees are often shorter and more rounded in cross section than leaves below
o can remain photosynthetically active for up to 50 years before they dropped to the forest floor
o most conifers retain individual leaves for a minimum of 2 to 5 years, leaving an impression that the leaves are evergreen
o some conifers are _-
fascicles
deciduous
59
D. Pinophyta
the sporophylls occur in __, which are spirally arranged shoots composed of modified leaves and branches
o __ cones are usually a few centimeters long with papery sporophylls
o __ cones are typically woody and can be up to 60 cm long
cones
pollen
ovulate
60
division of gymnosperms
the second largest group of gymnosperms consisting of 11 genera and 140 species
frequently mistaken for ferns or flowering palms rather than being recognized as relatives of conifers due to their frond-like or palm-like leaves
D. Cycadophyta (Cycads))
61
D. Cycadophyta
like conifers, cycads have __ which are generally larger than those of conifers, sometimes several meters in length
cones
62
D. Cycadophyta
have separate pollen and seed-producing plants (__)
o pollen and ovulate cones are both large, produced at the terminal portion of the trunk
o the ovulate cones of many species are pollinated by __
o cycad sperm are __, and swim the short distance to the egg, rupturing the pollen tube to ensure fertilization
dioecious
beetles
flagellated
63
D. Cycadophyta
the tallest cycads are 15 m, but many have short trunks
- trunks are covered with scaly leaf bases arranged __
spirally
64
the life cycle of cycads resembles that of a __
typical piine
65
D. Cycadophyta
living species are remnant of a much wider diversity found during the __ (245 to 65 million years ago), which is sometimes referred to not only as the Age of Dinosaurs but also as the __
Mesozoic era
Age of Cycads
66
the only living species of the division Ginkgophyta is __ commonly called maidenhair tree because of the resemblance of its leaves to those of maidenhair fern
Ginkgo biloba
67
o it is considered to be the oldest genus of extant seed plants based on fossil records
o a large, highly branched tree that resembles a woody angiosperm because of its laminar leaves and deciduous nature
o the pollen grain germinates and grows into the megasporagium
▪ megagametophytes give rise to fleshy seeds
▪ the fleshy seed coat can easily be mistaken for a fruit
Ginkgo
68
division of gymnosperms
like cycads and gnetophytes, Ginkgo has separate pollen and seed-producing plants (dioecious)
* the trees are commonly used for ornamental landscaping
o only the pollen-producing tree are used because seeds contain an acid that smells like rancid butter
o the seeds, embryo, and megagametophyte are popular in some cuisines
D. Ginkgophyta (Maidenhair Tree)
69
division of gymnosperms
members of the division are known as gnetophytes, include 70 species divided into three morphologically dissimilar genera: Ephedra, Gnetum and Welwitschia
o one significant feature they all share is the presence of vessel elements in their wood, a cell type absent in other gymnosperms
o their sperm is non-motile
o all are dioecious, except for some species of Ephedra
o Gnetum and Welwitschia are similar to angiosperms in not having archegonia
o Ephedra and Gnetum exhibit double fertilization producing extra embryo rather than an endosperm as in angiosperms
D. Gnetophyta (Gnetophytes)
70
genus in Gnetophytes
is a shrub-like plant with jointed stems and highly reduced leaves
o consists of more than 30 species
o restricted to desert and semi-desert habitats
o source of ephedrine, a drug used for the relief of allergic symptoms because of its ability to constrict blood vessels
Gnetum
71
genus in Gnetophytes
is a strange-looking gymnosperm and is probably the most unusual of all seed-producing plants
o consists only of one species, Welwitschia mirabilis, which is native to the arid coastal deserts of southwestern Africa
o it can survive the extremely drought condition by taking up water from the frequent coastal fogs
o with a carrot-shaped underground stem up to a meter in diameter and growing up to 3 m
o above ground, the stem produces two strap-like leaves that can measure up to 6 m
▪ the leaves have a meristem at their base and continue growing throughout the plant’s life
▪ but gradually split and break lengthwise giving the plant the appearance of having many leaves
o the male and female cones originate axils of leaves
o growth is unusually slow due to their dry environment
Welwitschia
72
More than 90% of extant plant species are flowering plants, and they represent an outstanding variety, from the water meal, an aquatic plant barely 1 mm long that grows in fresh water pond to terrestrial Eucalyptus, growing to a height of 92 m. The more than 250,000 species occur in more than 13,000 genera, which are grouped into more than 450 families under the division Magnoliophyta. Families are classified by the structure of flowers, fruits, leaves, and stems. Biochemical characteristics, such as presence or absence of particular alkaloids, are also important in classification. Members of a particular family usually share some traits related to these structures, even if convergent evolution has modified other traits.
Angiosperms (Flowering Plants)
73
Division __ includes both small and large plants that grow as herbs, shrubs, trees, woody and non-woody vines. They are the most widely distributed vascular plants, ranging from arid habitats to completely aquatic habitats, thus showing a high degree of adaptation.
Magnoliophyta
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Plants of Magnoliophyta are commonly referred to as __ (Greek angeion, vessel; sperma, seed). This indicates the nature of seed production in this division; seeds are enclosed within a vessel or the fruit.
angiosperms
75
The __ are the most abundant and familiar plants
around us. Included are grasses, roses, orchids, lilies, daisies, peas, beans, tomatoes, and cacti, just to name a few. They, in many ways, directly and indirectly, provide us with food, a source of building material, fiber for clothing, products of medicinal value, and many other useful substances.
angiosperms
76
evolution of angiosperms
RNA and DNA sequence data suggest that the lineage giving rise to flowering plants may have been separate from other seed plants for at least 280 million years
o this molecular evidence receives support from chemical analyses of rock strata, revealing the presence of the organic compound __ in rock deposits
dating from 290 to 235 million years ago
▪ __, compound that acts as defense against insects, is produced by flowering plants but not by gymnosperms
oleanane
77
angiosperms
traditionally, division Magnoliophyta had been dividedinto main classes based on the number of cotyledons: monocots (__) and dicots (__)
Liliopsida
Magnoliopsida
78
angiosperms
o approximately 70% of all angiosperm species are __ (about 170,000 species) and 30% are __ (about 65,000 species)
o it is believed that the monocots are of more recent origin than the dicots
o examples of monocots include all of the cereal grains (rice, wheat and corn) and other grasses, lilies, daffodils, pineapples, orchids, bananas, and palms
▪ with the exception of the __ and __, almost all of the monocots are non-woody herbaceous plants
▪ about 28% of angiosperm species
o common dicots include tomato, rose, sunflower, pea, bean, cucumber, apple, peach, cherry, mango, and acacia
▪ almost all of the flowering woody shrubs and trees are dicots
dicots
monocots
palms
bamboos
79
angiosperms
the most economically important family of Liliopsida is the __, the grass family, which includes all of the cereal grains, such as corn, wheat, rice, oats, barley, rye, and sorghum, as well as sugarcane and bamboo
Poaceae
80
angiosperms
the pargest monocot family
Orchidaceae (Orhicd family)
81
angiosperms
there are over 290 families of dicot plants, of which __ (the bean family), __ (the rose family), and __ (the sunflower family) are among the most common
Fabacaea
Rosaceae
Asteraceae
82
angiosperms
Ceratophyllaceae contains only one living genus, an aquatic plant, __
➢ they are reduced and simplified for life submerged in water
➢ they have no roots, and the small leaves lack stomata relying instead on diffusion for passage of gases
Ceratophyllum
83
evolution of flowers (angiosperms)
__ are believed to have evolved through a folding and fusion of leaves (sporophylls)
stamens
84
evolution of flowers (angiosperms)
the __ is also believed to have evolved from a sporophyll or leaf-like organ by folding
pistil
85
sexual reproduction among the __ is the most advanced of all the vascular plants
angiosperms
86
life cycle of angiosperms
like the gymnosperms, the angiosperms have a __,
during which two types of meiospores, microspores and megaspores, are produced
heterosporous life cycle
87
life cycle of angiosperms
the __ generation, represented by the flower-producing plant, is the dominant phase of the life cycle, with the highly reduced gametophyte generation being shortlived and completely dependent on the sporophyte plant
sporophyte
88
process in which the pollen grain, which is an immature microgametophvte, is released from the anther and is transferred to the stigma by means of wind, water, or other agents
pollination
89
process that occurs only in angiosperms - one of the sperm fertilizes the egg and the other sperm fuses with the polar nuclei
double fertilization
90
a phenomenon where a number of plants, such as bananas, pineapples, and certian varieties of grapes and melons, in which fruit development takes place even without fertilization
parthenocarpy
91
__ fruits are characterized by the absence of seeds,
a feature that is of economic value
parthonecarpic
92
(4) families in angiosperms
Family Poaceae (Grass Family)
Family Orchidaceae (Orchid Family)
Family Asteraceae (Compositae) (Sunflower Family)
Family Fabaceae (Leguminosae) (Legume Family)
93
family in angiosperms
* contains about 10,000 monocot species, including nearly all cereals, especially rice (Oryza) wheat (Triticum) and corn (Zea), the grain-producing plants, making it the most important family providing food for human
* most grasses are wind-pollinated
* most species have thin, relatively short stems, except bamboo with thick and tall stems
* grass flowers are not showy and may be bisexual or unisexual, depending on the species
* the anthers dangle on long, thin filaments, allowing the pollen to sift out into the breeze
o the pollen grains themselves are thin-walled and dry, which allows the wind to carry them farther
F. Poaceae/Grass
94
F. Poacea
fruit is a single-seeded caryopsis, a grain with a single, prominent cotyedon called a __ (Latin scutella, “small shield”)
scutellum
95
Poacea
corn is a grass with __ flowers
unisexual
96
Poacea
most grass species, however, have __ flowers
bisexual
97
family in angiosperms
* consist of monocots that form the largest family of plants
* orchids are herbaceous plants, many of which are epiphytes
* species estimates range between 20,000 and 38,000 because experts disagree on what is a variety and what is a species and also because rain forests contain many unknown species
* most orchid flowers are bilaterally symmetrical and have three or fewer of each type of modified leaf
* petals, for instance, are typically in groups of three, whereas there are typically one or two stamens
o the petals are large and showy, usually with two lateral petals flanking a central, flask-shaped petal with a large lip that accommodates pollinators
o paired anthers frequently detach from the plant as free structures called pollinia
* the fruit is a capsule and contains seeds that have no endosperm
o embryos are quite small compared with those of other plants, and seeds are shed when embryos are immature
▪ orchid seeds typically need a fungal partner in order
to germinate and initiate seedling development
F. Orchidacea/Orchid
98
family in angiosperm
* the largest family of eudicots and the second largest family in the plant kingdom, with more than 23,000 species of herbs, shrubs, and trees
* species are found worldwide but especially in temperate regions
* the flowers have complex head that are radially symmetrical
o they appear from a distance to be a single flower but are actually inflorescences, composites of many individual flowers, as you saw in a sunflower and daisies
o flies, butterflies, and bees are all attracted to the inflorescences of the various species in the family
o the sepals of many species are considerably modified to form bristles or scales that can be barbed or fluffy and assist in seed distribution, as in the case of dandelions
* the fruit is an achene, which is a thin, dry fruit containing a single seed that is attached to the fruit wall at only one point
o the hairs associated with the dandelion fruit are modified sepals
o sunflower "seeds" are actually an achene
F. Asteraceae/Sunflower/Compositae
99
family in angiosperms
* the third largest in the plant kingdom, containing more than 18,860 species of eudicots, including herbs, shrubs, trees, and vines found worldwide
* in most species, the bilaterally symmetrical flowers have one carpel, with other parts occurring in multiples of five
* fruits are frequently legumes, such as peas or beans
* seeds often have little or no endosperm, but embryos frequently have fleshy cotyledons that store considerable amounts of food
* leaves are alternate, compound, and pinnate
* some legumes display "sleep movements," elevating leaves in the morning and lowering them at night
* many species form mutualistic associations with nitrogen-fixing bacteria, which live in nodules on the roots
o thus, these legumes increase soil fertility and are extremely important to agriculture
F. Fabaceae/Leguminosae/Legume
