Flowering_plant

context: The flowering plants (angiosperms), also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants, with about 350,000 species. Like gymnosperms, angiosperms are seed-producing plants; they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, and the production of fruits that contain the seeds. Etymologically, angiosperm means a plant that produces seeds within an enclosure, in other words, a fruiting plant. The term "angiosperm" comes from the Greek composite word (angeion-, "case" or "casing", and sperma, "seed") meaning "enclosed seeds", after the enclosed condition of the seeds.
qas: answers: text: angiosperms
question: What are the most diverse group of land plants?

answers: text: 350,000
question: How many species of flowering plants are there about?

answers: text: an enclosure
question: What does an angiosperm produce its seeds within?

answers: text: seed-producing plants
question: What do angiosperms have in common with gymnosperms?

answers: text: angeion
question: What is the Greek word for "case" or "casing"?

context: Fossilized spores suggest that higher plants (embryophytes) have lived on land for at least 475 million years. Early land plants reproduced sexually with flagellated, swimming sperm, like the green algae from which they evolved. An adaptation to terrestrialization was the development of upright meiosporangia for dispersal by spores to new habitats. This feature is lacking in the descendants of their nearest algal relatives, the Charophycean green algae. A later terrestrial adaptation took place with retention of the delicate, avascular sexual stage, the gametophyte, within the tissues of the vascular sporophyte. This occurred by spore germination within sporangia rather than spore release, as in non-seed plants. A current example of how this might have happened can be seen in the precocious spore germination in Selaginella, the spike-moss. The result for the ancestors of angiosperms was enclosing them in a case, the seed. The first seed bearing plants, like the ginkgo, and conifers (such as pines and firs), did not produce flowers. The pollen grains (males) of Ginkgo and cycads produce a pair of flagellated, mobile sperm cells that "swim" down the developing pollen tube to the female and her eggs.
qas: answers: text: at least 475 million years
question: How long have higher plants lived on land?

answers: text: with flagellated, swimming sperm
question: How did early plants reproduce sexually?

answers: text: spores
question: Upright meisporangia allowed what to be dispersed to new habitats?

answers: text: Charophycean green algae
question: What are the nearest algal relatives existing today?

answers: text: the spike-moss
question: What is the common name for Selaginella?

context: The apparently sudden appearance of nearly modern flowers in the fossil record initially posed such a problem for the theory of evolution that it was called an "abominable mystery" by Charles Darwin. However, the fossil record has considerably grown since the time of Darwin, and recently discovered angiosperm fossils such as Archaefructus, along with further discoveries of fossil gymnosperms, suggest how angiosperm characteristics may have been acquired in a series of steps. Several groups of extinct gymnosperms, in particular seed ferns, have been proposed as the ancestors of flowering plants, but there is no continuous fossil evidence showing exactly how flowers evolved. Some older fossils, such as the upper Triassic Sanmiguelia, have been suggested. Based on current evidence, some propose that the ancestors of the angiosperms diverged from an unknown group of gymnosperms in the Triassic period (245–202 million years ago). Fossil angiosperm-like pollen from the Middle Triassic (247.2–242.0 Ma) suggests an older date for their origin. A close relationship between angiosperms and gnetophytes, proposed on the basis of morphological evidence, has more recently been disputed on the basis of molecular evidence that suggest gnetophytes are instead more closely related to other gymnosperms.[citation needed]
qas: answers: text: abominable mystery
question: What did Charles Darwin call the sudden appearance of nearly modern flowers in the fossil record?

answers: text: angiosperm
question: What type of fossil is the recently discovered Archaefructus?

answers: text: evidence showing exactly how flowers evolved
question: What fossil evidence is lacking when it comes to flowers?

answers: text: Middle Triassic
question: From what period does fossilized pollen suggest an older date for angiosperm origin?

answers: text: relationship between angiosperms and gnetophytes
question: What relationship proposed on the basis of morphological evidence has recently been disputed?

context: The evolution of seed plants and later angiosperms appears to be the result of two distinct rounds of whole genome duplication events. These occurred at 319 million years ago and 192 million years ago. Another possible whole genome duplication event at 160 million years ago perhaps created the ancestral line that led to all modern flowering plants. That event was studied by sequencing the genome of an ancient flowering plant, Amborella trichopoda, and directly addresses Darwin's "abominable mystery."
qas: answers: text: two
question: How many distinct rounds of genome duplication events are suspected in the evolution of seed plants?

answers: text: 319 million years ago
question: When did the first whole genome duplication event occur?

answers: text: whole genome duplication
question: What type of event perhaps created the line which led to modern flowering plants?

answers: text: by sequencing the genome of an ancient flowering plant
question: How are duplication events studied?

answers: text: Darwin
question: Who coined the term "abominable mystery"?

context: The earliest known macrofossil confidently identified as an angiosperm, Archaefructus liaoningensis, is dated to about 125 million years BP (the Cretaceous period), whereas pollen considered to be of angiosperm origin takes the fossil record back to about 130 million years BP. However, one study has suggested that the early-middle Jurassic plant Schmeissneria, traditionally considered a type of ginkgo, may be the earliest known angiosperm, or at least a close relative. In addition, circumstantial chemical evidence has been found for the existence of angiosperms as early as 250 million years ago. Oleanane, a secondary metabolite produced by many flowering plants, has been found in Permian deposits of that age together with fossils of gigantopterids. Gigantopterids are a group of extinct seed plants that share many morphological traits with flowering plants, although they are not known to have been flowering plants themselves.
qas: answers: text: about 125 million years BP
question: When is the earliest known macrofossil identified as an angiosperm dated?

answers: text: Archaefructus liaoningensis
question: What is the earliest known angiosperm?

answers: text: pollen
question: What pushes the age of angiosperm 5 million years further back?

answers: text: 250 million years ago
question: How long ago has circumstantial evidence has been found for the existence of angiosperms?

answers: text: Gigantopterids
question: What group of now extinct seed plants had many of the traits of what are now flowering plants?

context: The great angiosperm radiation, when a great diversity of angiosperms appears in the fossil record, occurred in the mid-Cretaceous (approximately 100 million years ago). However, a study in 2007 estimated that the division of the five most recent (the genus Ceratophyllum, the family Chloranthaceae, the eudicots, the magnoliids, and the monocots) of the eight main groups occurred around 140 million years ago. By the late Cretaceous, angiosperms appear to have dominated environments formerly occupied by ferns and cycadophytes, but large canopy-forming trees replaced conifers as the dominant trees only close to the end of the Cretaceous 66 million years ago or even later, at the beginning of the Tertiary. The radiation of herbaceous angiosperms occurred much later. Yet, many fossil plants recognizable as belonging to modern families (including beech, oak, maple, and magnolia) had already appeared by the late Cretaceous.
qas: answers: text: approximately 100 million years ago
question: When does a great diversity of angiosperms appear in the fossil record?

answers: text: great angiosperm radiation,
question: What is the appearance of a large amount of angiosperms in the fossil record known as?

answers: text: 40 million years ago
question: When did the division of the eight main groups of angiosperms occur?

answers: text: dominated environments
question: What were the angiosperms up to by the late Cretaceous?

answers: text: Cretaceous
question: Beech and maple had already appeared by what period?

context: Island genetics provides one proposed explanation for the sudden, fully developed appearance of flowering plants. Island genetics is believed to be a common source of speciation in general, especially when it comes to radical adaptations that seem to have required inferior transitional forms. Flowering plants may have evolved in an isolated setting like an island or island chain, where the plants bearing them were able to develop a highly specialized relationship with some specific animal (a wasp, for example). Such a relationship, with a hypothetical wasp carrying pollen from one plant to another much the way fig wasps do today, could result in the development of a high degree of specialization in both the plant(s) and their partners. Note that the wasp example is not incidental; bees, which, it is postulated, evolved specifically due to mutualistic plant relationships, are descended from wasps.
qas: answers: text: Island genetics
question: What is one proposed explanation for the instant appearance of flowering plants?

answers: text: speciation
question: What is island genetics thought to be a default source of?

answers: text: inferior transitional forms
question: What did radical adaptations seem to have required?

answers: text: highly specialized relationship with some specific animal
question: How did an isolated setting like an island help flowering plants evolve?

answers: text: wasps
question: What are bees descended from?

context: Animals are also involved in the distribution of seeds. Fruit, which is formed by the enlargement of flower parts, is frequently a seed-dispersal tool that attracts animals to eat or otherwise disturb it, incidentally scattering the seeds it contains (see frugivory). Although many such mutualistic relationships remain too fragile to survive competition and to spread widely, flowering proved to be an unusually effective means of reproduction, spreading (whatever its origin) to become the dominant form of land plant life.
qas: answers: text: distribution of seeds
question: What are animals also a part of?

answers: text: Fruit
question: What did the enlargement of flower parts evolve to form?

answers: text: seed-dispersal
question: What does a plant get out of forming fruit?

answers: text: fragile
question: What are many mutualistic relationships, thus failing to survive competition? 

answers: text: flowering
question: What turned out to be unusually effective for plants to reproduce?

context: Flower ontogeny uses a combination of genes normally responsible for forming new shoots. The most primitive flowers probably had a variable number of flower parts, often separate from (but in contact with) each other. The flowers tended to grow in a spiral pattern, to be bisexual (in plants, this means both male and female parts on the same flower), and to be dominated by the ovary (female part). As flowers evolved, some variations developed parts fused together, with a much more specific number and design, and with either specific sexes per flower or plant or at least "ovary-inferior".
qas: answers: text: Flower ontogeny
question: What uses a combination of genes to form new shoots?

answers: text: separate from (but in contact with) each other
question: What were plant parts like in their primitive days?

answers: text: grow in a spiral pattern
question: How did flowers become bixsexual?

answers: text: fused together
question: What did some plant parts do as they evolved?

answers: text: "ovary-inferior"
question: What is a term for a plant with a specific sex per flower?

context: Flower evolution continues to the present day; modern flowers have been so profoundly influenced by humans that some of them cannot be pollinated in nature. Many modern domesticated flower species were formerly simple weeds, which sprouted only when the ground was disturbed. Some of them tended to grow with human crops, perhaps already having symbiotic companion plant relationships with them, and the prettiest did not get plucked because of their beauty, developing a dependence upon and special adaptation to human affection.
qas: answers: text: present day
question: How long has flower evolution occurred? 

answers: text: formerly simple weeds
question: What heritage do many modern domesticated flower species have?

answers: text: pollinated
question: Humans have effected some flowers so much they can no longer do what in nature?

answers: text: symbiotic companion plant relationships
question: Why did weeds grow with human crops?

answers: text: prettiest
question: What feature helped flowers not get plucked?

context: The exact relationship between these eight groups is not yet clear, although there is agreement that the first three groups to diverge from the ancestral angiosperm were Amborellales, Nymphaeales, and Austrobaileyales. The term basal angiosperms refers to these three groups. Among the rest, the relationship between the three broadest of these groups (magnoliids, monocots, and eudicots) remains unclear. Some analyses make the magnoliids the first to diverge, others the monocots. Ceratophyllum seems to group with the eudicots rather than with the monocots.
qas: answers: text: Amborellales, Nymphaeales, and Austrobaileyales
question: What three groups were the first to diverge from angiosperm?

answers: text: basal
question: What term refers to the first three groups to diverge from angiosperm?

answers: text: unclear
question: How clear is the relationship between the broadest of the three non-basal angiosperm groups?

answers: text: magnoliids
question: What group do some analyses seem to indicate diverged first?

context: The botanical term "Angiosperm", from the Ancient Greek αγγείον, angeíon (bottle, vessel) and σπέρμα, (seed), was coined in the form Angiospermae by Paul Hermann in 1690, as the name of one of his primary divisions of the plant kingdom. This included flowering plants possessing seeds enclosed in capsules, distinguished from his Gymnospermae, or flowering plants with achenial or schizo-carpic fruits, the whole fruit or each of its pieces being here regarded as a seed and naked. The term and its antonym were maintained by Carl Linnaeus with the same sense, but with restricted application, in the names of the orders of his class Didynamia. Its use with any approach to its modern scope became possible only after 1827, when Robert Brown established the existence of truly naked ovules in the Cycadeae and Coniferae, and applied to them the name Gymnosperms.[citation needed] From that time onward, as long as these Gymnosperms were, as was usual, reckoned as dicotyledonous flowering plants, the term Angiosperm was used antithetically by botanical writers, with varying scope, as a group-name for other dicotyledonous plants.
qas: answers: text: Angiosperm
question: What term did Paul Hermann come up with in 1690?

answers: text: primary
question: What did Hermann use the term angiosperm a primary division of in the plant kingdom?

answers: text: Carl Linnaeus
question: Who restricted the application of the angiosperm term?

answers: text: naked ovules
question: What did Robert Brown establish the existence of in Cycadeae and Coniferae?

answers: text: other dicotyledonous plants
question: What is the group-name angiosperm has been used for by botanical writers?

context: In most taxonomies, the flowering plants are treated as a coherent group. The most popular descriptive name has been Angiospermae (Angiosperms), with Anthophyta ("flowering plants") a second choice. These names are not linked to any rank. The Wettstein system and the Engler system use the name Angiospermae, at the assigned rank of subdivision. The Reveal system treated flowering plants as subdivision Magnoliophytina (Frohne & U. Jensen ex Reveal, Phytologia 79: 70 1996), but later split it to Magnoliopsida, Liliopsida, and Rosopsida. The Takhtajan system and Cronquist system treat this group at the rank of division, leading to the name Magnoliophyta (from the family name Magnoliaceae). The Dahlgren system and Thorne system (1992) treat this group at the rank of class, leading to the name Magnoliopsida. The APG system of 1998, and the later 2003 and 2009 revisions, treat the flowering plants as a clade called angiosperms without a formal botanical name. However, a formal classification was published alongside the 2009 revision in which the flowering plants form the Subclass Magnoliidae.
qas: answers: text: coherent
question: In taxonomies, what type of group are flowering plants treated?

answers: text: flowering plants
question: What does anthophyta mean?

answers: text: Angiospermae
question: What do the Wettstein and Engler systems use at the assigned rank of subdivision?

answers: text: a clade called angiosperms
question: How does the APG system of 1998, with its 2003 and 2009 revisions, treat flowering plants?

answers: text: Magnoliidae
question: What formal subclass classification were flowering plants given in 2009?

context: The internal classification of this group has undergone considerable revision. The Cronquist system, proposed by Arthur Cronquist in 1968 and published in its full form in 1981, is still widely used but is no longer believed to accurately reflect phylogeny. A consensus about how the flowering plants should be arranged has recently begun to emerge through the work of the Angiosperm Phylogeny Group (APG), which published an influential reclassification of the angiosperms in 1998. Updates incorporating more recent research were published as APG II in 2003 and as APG III in 2009.
qas: answers: text: how the flowering plants should be arranged
question: What consensus is the AGP trying to reach?

answers: text: classification
question: What internal component has undergone considerable revision?

answers: text: The Cronquist system
question: What system did Arthur Cronquist put forth in 1968, but not publish in full form until 1981?

answers: text: APG
question: Who published an influential reclassification of the angiosperms in 1998?

context: Recent studies, as by the APG, show that the monocots form a monophyletic group (clade) but that the dicots do not (they are paraphyletic). Nevertheless, the majority of dicot species do form a monophyletic group, called the eudicots or tricolpates. Of the remaining dicot species, most belong to a third major clade known as the magnoliids, containing about 9,000 species. The rest include a paraphyletic grouping of primitive species known collectively as the basal angiosperms, plus the families Ceratophyllaceae and Chloranthaceae.
qas: answers: text: monophyletic
question: What type of groups do monocots form, based on a recent APG studies?

answers: text: dicot
question: Eudicots or tricolpates are part of a monophyletic group formed by what species?

answers: text: magnoliids
question: What third major clade can many dicot species be found in?

answers: text: about 9,000
question: How many species dicot species are magnoliids?

answers: text: paraphyletic
question: Basal angiosperms are what type of grouping of primitive species?

context: The number of species of flowering plants is estimated to be in the range of 250,000 to 400,000. This compares to around 12,000 species of moss or 11,000 species of pteridophytes, showing that the flowering plants are much more diverse. The number of families in APG (1998) was 462. In APG II (2003) it is not settled; at maximum it is 457, but within this number there are 55 optional segregates, so that the minimum number of families in this system is 402. In APG III (2009) there are 415 families.
qas: answers: text: 250,000 to 400,000
question: What is the estimated range for the number of flowering plants?

answers: text: 12,000
question: How many species of moss is there?

answers: text: diverse
question: What does the large number of flowering plant species indicate is true of them in general?

answers: text: 402
question: What are the minimum number of families in the APG system?

answers: text: 415
question: How many families are in AGP III?

context: In the dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium. By the formation of a layer of cambium between the bundles (interfascicular cambium), a complete ring is formed, and a regular periodical increase in thickness results from the development of xylem on the inside and phloem on the outside. The soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Owing to differences in the character of the elements produced at the beginning and end of the season, the wood is marked out in transverse section into concentric rings, one for each season of growth, called annual rings.
qas: answers: text: an open ring
question: What shape are the bundles in the young stem of dicotyledons arranged in?

answers: text: xylem and phloem
question: What does the cambium separate?

answers: text: cambium
question: What is a layer of meristem or formative tissue known as?

answers: text: increase in thickness
question: What results from the development of xylem on the inside and phloem on the outside?

answers: text: annual rings
question: What's another name for the concentric rings in trees?

context: The characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species. The function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf (where the petiole attaches to the stem). Occasionally, as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. More typically, the flower-bearing portion of the plant is sharply distinguished from the foliage-bearing or vegetative portion, and forms a more or less elaborate branch-system called an inflorescence.
qas: answers: text: flower
question: What is the defining feature of angiosperms?

answers: text: form and elaboration
question: What characteristic flowers show variation in?

answers: text: establishing relationships among angiosperm species
question: What do flowers provide the best external feature for doing?

answers: text: the ovule
question: What is it the function of the flower to ensure fertilization of?

answers: text: inflorescence
question: What is the name of a branch system?

context: The flower may consist only of these parts, as in willow, where each flower comprises only a few stamens or two carpels. Usually, other structures are present and serve to protect the sporophylls and to form an envelope attractive to pollinators. The individual members of these surrounding structures are known as sepals and petals (or tepals in flowers such as Magnolia where sepals and petals are not distinguishable from each other). The outer series (calyx of sepals) is usually green and leaf-like, and functions to protect the rest of the flower, especially the bud. The inner series (corolla of petals) is, in general, white or brightly colored, and is more delicate in structure. It functions to attract insect or bird pollinators. Attraction is effected by color, scent, and nectar, which may be secreted in some part of the flower. The characteristics that attract pollinators account for the popularity of flowers and flowering plants among humans.
qas: answers: text: only a few stamens or two carpels
question: What is a willow's flower comprised of?

answers: text: the sporophylls
question: What have some structures evolved to protect?

answers: text: green and leaf-like
question: What appearance are calyx of sepals typically?

answers: text: sepals and petals
question: Individual members of enveloping structures are known by what terms?

answers: text: humans
question: The features of flowers which attract pollinators also attract what other creature?

context: While the majority of flowers are perfect or hermaphrodite (having both pollen and ovule producing parts in the same flower structure), flowering plants have developed numerous morphological and physiological mechanisms to reduce or prevent self-fertilization. Heteromorphic flowers have short carpels and long stamens, or vice versa, so animal pollinators cannot easily transfer pollen to the pistil (receptive part of the carpel). Homomorphic flowers may employ a biochemical (physiological) mechanism called self-incompatibility to discriminate between self and non-self pollen grains. In other species, the male and female parts are morphologically separated, developing on different flowers.
qas: answers: text: hermaphrodite
question: What sexual feature do a majority of flowers demonstrate?

answers: text: reduce or prevent self-fertilization
question: Why did flowering plants develop numerous morphological and physiological mechanisms?

answers: text: so animal pollinators cannot easily transfer pollen to the pistil
question: Why are a heteromorphic flower's carpels and stamens different lengths?

answers: text: biochemical
question: What type of mechanism might homomorphic flowers use to tell the difference between foreign and self pollen grains?

answers: text: different flowers
question: How are some male and female parts separated for some species?

context: Double fertilization refers to a process in which two sperm cells fertilize cells in the ovary. This process begins when a pollen grain adheres to the stigma of the pistil (female reproductive structure), germinates, and grows a long pollen tube. While this pollen tube is growing, a haploid generative cell travels down the tube behind the tube nucleus. The generative cell divides by mitosis to produce two haploid (n) sperm cells. As the pollen tube grows, it makes its way from the stigma, down the style and into the ovary. Here the pollen tube reaches the micropyle of the ovule and digests its way into one of the synergids, releasing its contents (which include the sperm cells). The synergid that the cells were released into degenerates and one sperm makes its way to fertilize the egg cell, producing a diploid (2n) zygote. The second sperm cell fuses with both central cell nuclei, producing a triploid (3n) cell. As the zygote develops into an embryo, the triploid cell develops into the endosperm, which serves as the embryo's food supply. The ovary now will develop into fruit and the ovule will develop into seed.
qas: answers: text: two sperm cells fertilize cells in the ovary
question: What process does double fertilization refer to?

answers: text: the stigma of the pistil
question: What does a pollen grain adhere to, to start the process of double fertilization?

answers: text: haploid generative
question: What type of cell travels down the pollen tube while it's growing?

answers: text: one of the synergids
question: Where does the pollen tube release its sperm cells?

answers: text: endosperm
question: What serves as the embryo's food supply?

context: The character of the seed coat bears a definite relation to that of the fruit. They protect the embryo and aid in dissemination; they may also directly promote germination. Among plants with indehiscent fruits, in general, the fruit provides protection for the embryo and secures dissemination. In this case, the seed coat is only slightly developed. If the fruit is dehiscent and the seed is exposed, in general, the seed-coat is well developed, and must discharge the functions otherwise executed by the fruit.
qas: answers: text: the fruit
question: The appearance of the seed coat bears a definite relation to that of what?

answers: text: embryo
question: What does the seed coat protect?

answers: text: dissemination
question: What does the fruit of the flower secure?

answers: text: slightly
question: How developed is the seed coat when it's used for dissemination?

context: Agriculture is almost entirely dependent on angiosperms, which provide virtually all plant-based food, and also provide a significant amount of livestock feed. Of all the families of plants, the Poaceae, or grass family (grains), is by far the most important, providing the bulk of all feedstocks (rice, corn — maize, wheat, barley, rye, oats, pearl millet, sugar cane, sorghum). The Fabaceae, or legume family, comes in second place. Also of high importance are the Solanaceae, or nightshade family (potatoes, tomatoes, and peppers, among others), the Cucurbitaceae, or gourd family (also including pumpkins and melons), the Brassicaceae, or mustard plant family (including rapeseed and the innumerable varieties of the cabbage species Brassica oleracea), and the Apiaceae, or parsley family. Many of our fruits come from the Rutaceae, or rue family (including oranges, lemons, grapefruits, etc.), and the Rosaceae, or rose family (including apples, pears, cherries, apricots, plums, etc.).
qas: answers: text: angiosperms
question: On what is agriculture almost completely dependent?

answers: text: Poaceae
question: What family of plants is most important for human sustenance?

answers: text: legume
question: What is the more common name of the Fabaceae?

answers: text: Solanaceae
question: What family do potatoes, tomatoes and peppers belong to?

answers: text: Rosaceae
question: What family would you find cherries in?