nc33/MultiSpan_SQUAD huggingface dataset:
Flowering_plant

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.

Question: How long have higher plants lived on land?
Answer: at least 475 million years

Question: How did early plants reproduce sexually?
Answer: with flagellated, swimming sperm

Question: Upright meisporangia allowed what to be dispersed to new habitats?
Answer: spores

Question: What are the nearest algal relatives existing today?
Answer: Charophycean green algae

Question: What is the common name for Selaginella?
Answer: the spike-moss
Flowering_plant

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]

Question: What did Charles Darwin call the sudden appearance of nearly modern flowers in the fossil record?
Answer: abominable mystery

Question: What type of fossil is the recently discovered Archaefructus?
Answer: angiosperm

Question: What fossil evidence is lacking when it comes to flowers?
Answer: evidence showing exactly how flowers evolved

Question: From what period does fossilized pollen suggest an older date for angiosperm origin?
Answer: Middle Triassic

Question: What relationship proposed on the basis of morphological evidence has recently been disputed?
Answer: relationship between angiosperms and gnetophytes
Flowering_plant

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."

Question: How many distinct rounds of genome duplication events are suspected in the evolution of seed plants?
Answer: two

Question: When did the first whole genome duplication event occur?
Answer: 319 million years ago

Question: What type of event perhaps created the line which led to modern flowering plants?
Answer: whole genome duplication

Question: How are duplication events studied?
Answer: by sequencing the genome of an ancient flowering plant

Question: Who coined the term "abominable mystery"?
Answer: Darwin
Flowering_plant

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.

Question: When is the earliest known macrofossil identified as an angiosperm dated?
Answer: about 125 million years BP

Question: What is the earliest known angiosperm?
Answer: Archaefructus liaoningensis

Question: What pushes the age of angiosperm 5 million years further back?
Answer: pollen

Question: How long ago has circumstantial evidence has been found for the existence of angiosperms?
Answer: 250 million years ago

Question: What group of now extinct seed plants had many of the traits of what are now flowering plants?
Answer: Gigantopterids
Flowering_plant

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.

Question: What is one proposed explanation for the instant appearance of flowering plants?
Answer: Island genetics

Question: What is island genetics thought to be a default source of?
Answer: speciation

Question: What did radical adaptations seem to have required?
Answer: inferior transitional forms

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

Question: What are bees descended from?
Answer: wasps
Flowering_plant

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.

Question: What are animals also a part of?
Answer: distribution of seeds

Question: What did the enlargement of flower parts evolve to form?
Answer: Fruit

Question: What does a plant get out of forming fruit?
Answer: seed-dispersal

Question: What are many mutualistic relationships, thus failing to survive competition? 
Answer: fragile

Question: What turned out to be unusually effective for plants to reproduce?
Answer: flowering
Flowering_plant

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".

Question: What uses a combination of genes to form new shoots?
Answer: Flower ontogeny

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

Question: How did flowers become bixsexual?
Answer: grow in a spiral pattern

Question: What did some plant parts do as they evolved?
Answer: fused together

Question: What is a term for a plant with a specific sex per flower?
Answer: "ovary-inferior"
Flowering_plant

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.

Question: How long has flower evolution occurred? 
Answer: present day

Question: What heritage do many modern domesticated flower species have?
Answer: formerly simple weeds

Question: Humans have effected some flowers so much they can no longer do what in nature?
Answer: pollinated

Question: Why did weeds grow with human crops?
Answer: symbiotic companion plant relationships

Question: What feature helped flowers not get plucked?
Answer: prettiest
Flowering_plant

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.

Question: What three groups were the first to diverge from angiosperm?
Answer: Amborellales, Nymphaeales, and Austrobaileyales

Question: What term refers to the first three groups to diverge from angiosperm?
Answer: basal

Question: How clear is the relationship between the broadest of the three non-basal angiosperm groups?
Answer: unclear

Question: What group do some analyses seem to indicate diverged first?
Answer: magnoliids
Flowering_plant

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.

Question: What term did Paul Hermann come up with in 1690?
Answer: Angiosperm

Question: What did Hermann use the term angiosperm a primary division of in the plant kingdom?
Answer: primary

Question: Who restricted the application of the angiosperm term?
Answer: Carl Linnaeus

Question: What did Robert Brown establish the existence of in Cycadeae and Coniferae?
Answer: naked ovules

Question: What is the group-name angiosperm has been used for by botanical writers?
Answer: other dicotyledonous plants
Flowering_plant

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.

Question: In taxonomies, what type of group are flowering plants treated?
Answer: coherent

Question: What does anthophyta mean?
Answer: flowering plants

Question: What do the Wettstein and Engler systems use at the assigned rank of subdivision?
Answer: Angiospermae

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

Question: What formal subclass classification were flowering plants given in 2009?
Answer: Magnoliidae
Flowering_plant

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.

Question: What consensus is the AGP trying to reach?
Answer: how the flowering plants should be arranged

Question: What internal component has undergone considerable revision?
Answer: classification

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

Question: Who published an influential reclassification of the angiosperms in 1998?
Answer: APG
Flowering_plant

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.

Question: What type of groups do monocots form, based on a recent APG studies?
Answer: monophyletic

Question: Eudicots or tricolpates are part of a monophyletic group formed by what species?
Answer: dicot

Question: What third major clade can many dicot species be found in?
Answer: magnoliids

Question: How many species dicot species are magnoliids?
Answer: about 9,000

Question: Basal angiosperms are what type of grouping of primitive species?
Answer: paraphyletic
Flowering_plant

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.

Question: What is the estimated range for the number of flowering plants?
Answer: 250,000 to 400,000

Question: How many species of moss is there?
Answer: 12,000

Question: What does the large number of flowering plant species indicate is true of them in general?
Answer: diverse

Question: What are the minimum number of families in the APG system?
Answer: 402

Question: How many families are in AGP III?
Answer: 415
Flowering_plant

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.

Question: What shape are the bundles in the young stem of dicotyledons arranged in?
Answer: an open ring

Question: What does the cambium separate?
Answer: xylem and phloem

Question: What is a layer of meristem or formative tissue known as?
Answer: cambium

Question: What results from the development of xylem on the inside and phloem on the outside?
Answer: increase in thickness

Question: What's another name for the concentric rings in trees?
Answer: annual rings
Flowering_plant

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.

Question: What is the defining feature of angiosperms?
Answer: flower

Question: What characteristic flowers show variation in?
Answer: form and elaboration

Question: What do flowers provide the best external feature for doing?
Answer: establishing relationships among angiosperm species

Question: What is it the function of the flower to ensure fertilization of?
Answer: the ovule

Question: What is the name of a branch system?
Answer: inflorescence
Flowering_plant

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.

Question: What is a willow's flower comprised of?
Answer: only a few stamens or two carpels

Question: What have some structures evolved to protect?
Answer: the sporophylls

Question: What appearance are calyx of sepals typically?
Answer: green and leaf-like

Question: Individual members of enveloping structures are known by what terms?
Answer: sepals and petals

Question: The features of flowers which attract pollinators also attract what other creature?
Answer: humans
Flowering_plant

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.

Question: What sexual feature do a majority of flowers demonstrate?
Answer: hermaphrodite

Question: Why did flowering plants develop numerous morphological and physiological mechanisms?
Answer: reduce or prevent self-fertilization

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

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

Question: How are some male and female parts separated for some species?
Answer: different flowers