rajpurkar/squad huggingface dataset:
Title: Annelid

Feeding structures in the mouth region vary widely, and have little correlation with the animals' diets. Many polychaetes have a muscular pharynx that can be everted (turned inside out to extend it). In these animals the foremost few segments often lack septa so that, when the muscles in these segments contract, the sharp increase in fluid pressure from all these segments everts the pharynx very quickly. Two families, the Eunicidae and Phyllodocidae, have evolved jaws, which can be used for seizing prey, biting off pieces of vegetation, or grasping dead and decaying matter. On the other hand, some predatory polychaetes have neither jaws nor eversible pharynges. Selective deposit feeders generally live in tubes on the sea-floor and use palps to find food particles in the sediment and then wipe them into their mouths. Filter feeders use "crowns" of palps covered in cilia that wash food particles towards their mouths. Non-selective deposit feeders ingest soil or marine sediments via mouths that are generally unspecialized. Some clitellates have sticky pads in the roofs of their mouths, and some of these can evert the pads to capture prey. Leeches often have an eversible proboscis, or a muscular pharynx with two or three teeth.

Question: What does 'everted' mean?
Answer: turned inside out to extend

Question: What part of a polychaete can be everted?
Answer: pharynx

Question: What types of annelids have evolved jaws?
Answer: Eunicidae and Phyllodocidae

Question: What do annelids use jaws for?
Answer: seizing prey, biting off pieces of vegetation, or grasping dead and decaying matter

Question: What do some annelids have 'crowns' of?
Answer: palps covered in cilia
Title: Annelid

The gut is generally an almost straight tube supported by the mesenteries (vertical partitions within segments), and ends with the anus on the underside of the pygidium. However, in members of the tube-dwelling family Siboglinidae the gut is blocked by a swollen lining that houses symbiotic bacteria, which can make up 15% of the worms' total weight. The bacteria convert inorganic matter – such as hydrogen sulfide and carbon dioxide from hydrothermal vents, or methane from seeps – to organic matter that feeds themselves and their hosts, while the worms extend their palps into the gas flows to absorb the gases needed by the bacteria.

Question: What type of annelids are tube-dwelling?
Answer: Siboglinidae

Question: What blocks the Siboglinidae's gut?
Answer: a swollen lining

Question: How much of a Siboglinidae's weight is symbiotic bacteria?
Answer: 15%

Question: What gases come from hydrothermal vents?
Answer: hydrogen sulfide and carbon dioxide

Question: What gases come from seeps?
Answer: methane
Title: Annelid

Annelids with blood vessels use metanephridia to remove soluble waste products, while those without use protonephridia. Both of these systems use a two-stage filtration process, in which fluid and waste products are first extracted and these are filtered again to re-absorb any re-usable materials while dumping toxic and spent materials as urine. The difference is that protonephridia combine both filtration stages in the same organ, while metanephridia perform only the second filtration and rely on other mechanisms for the first – in annelids special filter cells in the walls of the blood vessels let fluids and other small molecules pass into the coelomic fluid, where it circulates to the metanephridia. In annelids the points at which fluid enters the protonephridia or metanephridia are on the forward side of a septum while the second-stage filter and the nephridiopore (exit opening in the body wall) are in the following segment. As a result, the hindmost segment (before the growth zone and pygidium) has no structure that extracts its wastes, as there is no following segment to filter and discharge them, while the first segment contains an extraction structure that passes wastes to the second, but does not contain the structures that re-filter and discharge urine.

Question: What do metanephridia remove?
Answer: soluble waste products

Question: What do annelids without blood vessels do to remove waste?
Answer: protonephridia

Question: How many stages are there in annelids' waste filtration?
Answer: two

Question: What annelid system combines both filtration states in one organ?
Answer: protonephridia
Title: Annelid

It is thought that annelids were originally animals with two separate sexes, which released ova and sperm into the water via their nephridia. The fertilized eggs develop into trochophore larvae, which live as plankton. Later they sink to the sea-floor and metamorphose into miniature adults: the part of the trochophore between the apical tuft and the prototroch becomes the prostomium (head); a small area round the trochophore's anus becomes the pygidium (tail-piece); a narrow band immediately in front of that becomes the growth zone that produces new segments; and the rest of the trochophore becomes the peristomium (the segment that contains the mouth).

Question: How many sexes of annelids were there originally?
Answer: two

Question: What releases sperm from annelids?
Answer: nephridia

Question: What do annelid eggs become?
Answer: trochophore larvae

Question: What do annelids' larvae live like?
Answer: plankton

Question: What does the trochophore become when annelids mature?
Answer: the prostomium (head)
Title: Annelid

However, the lifecycles of most living polychaetes, which are almost all marine animals, are unknown, and only about 25% of the 300+ species whose lifecycles are known follow this pattern. About 14% use a similar external fertilization but produce yolk-rich eggs, which reduce the time the larva needs to spend among the plankton, or eggs from which miniature adults emerge rather than larvae. The rest care for the fertilized eggs until they hatch – some by producing jelly-covered masses of eggs which they tend, some by attaching the eggs to their bodies and a few species by keeping the eggs within their bodies until they hatch. These species use a variety of methods for sperm transfer; for example, in some the females collect sperm released into the water, while in others the males have a penis that inject sperm into the female. There is no guarantee that this is a representative sample of polychaetes' reproductive patterns, and it simply reflects scientists' current knowledge.

Question: How many species of polychaetes have known lifecycles?
Answer: about 25%

Question: What percent of polychaetes produce yolk-rich eggs?
Answer: 14%

Question: What is the benefit of yolk-rich eggs?
Answer: reduce the time the larva needs to spend among the plankton

Question: What are most polychaetes' eggs covered in?
Answer: jelly
Title: Annelid

Some polychaetes breed only once in their lives, while others breed almost continuously or through several breeding seasons. While most polychaetes remain of one sex all their lives, a significant percentage of species are full hermaphrodites or change sex during their lives. Most polychaetes whose reproduction has been studied lack permanent gonads, and it is uncertain how they produce ova and sperm. In a few species the rear of the body splits off and becomes a separate individual that lives just long enough to swim to a suitable environment, usually near the surface, and spawn.

Question: What do some non-single-sex polychaetes do?
Answer: change sex

Question: What are most polychaetes lacking for reproduction?
Answer: permanent gonads

Question: How do some annelids get a one-time chance at a better spawning spot?
Answer: the rear of the body splits off and becomes a separate individual
Title: Annelid

Most mature clitellates (the group that includes earthworms and leeches) are full hermaphrodites, although in a few leech species younger adults function as males and become female at maturity. All have well-developed gonads, and all copulate. Earthworms store their partners' sperm in spermathecae ("sperm stores") and then the clitellum produces a cocoon that collects ova from the ovaries and then sperm from the spermathecae. Fertilization and development of earthworm eggs takes place in the cocoon. Leeches' eggs are fertilized in the ovaries, and then transferred to the cocoon. In all clitellates the cocoon also either produces yolk when the eggs are fertilized or nutrients while they are developing. All clitellates hatch as miniature adults rather than larvae.

Question: What annelid group includes leeches and earthworms?
Answer: clitellates

Question: What type of sex are most earthworms?
Answer: hermaphrodites

Question: Where are leeches' eggs fertilized?
Answer: in the ovaries

Question: Where do leeches move their eggs to?
Answer: the cocoon

Question: What type of annelids hatch as miniature adults?
Answer: clitellates
Title: Annelid

Charles Darwin's book The Formation of Vegetable Mould through the Action of Worms (1881) presented the first scientific analysis of earthworms' contributions to soil fertility. Some burrow while others live entirely on the surface, generally in moist leaf litter. The burrowers loosen the soil so that oxygen and water can penetrate it, and both surface and burrowing worms help to produce soil by mixing organic and mineral matter, by accelerating the decomposition of organic matter and thus making it more quickly available to other organisms, and by concentrating minerals and converting them to forms that plants can use more easily. Earthworms are also important prey for birds ranging in size from robins to storks, and for mammals ranging from shrews to badgers, and in some cases conserving earthworms may be essential for conserving endangered birds.

Question: Who published a book about worms in 1881?
Answer: Charles Darwin

Question: What was the first scientific study of how earthworms help soil?
Answer: The Formation of Vegetable Mould through the Action of Worms

Question: Where do earthworms prefer to live on the surface?
Answer: generally in moist leaf litter

Question: How does burrowers' loosening help the soil?
Answer: oxygen and water can penetrate it

Question: What is the largest bird that eats earthworms?
Answer: storks
Title: Annelid

Terrestrial annelids can be invasive in some situations. In the glaciated areas of North America, for example, almost all native earthworms are thought to have been killed by the glaciers and the worms currently found in those areas are all introduced from other areas, primarily from Europe, and, more recently, from Asia. Northern hardwood forests are especially negatively impacted by invasive worms through the loss of leaf duff, soil fertility, changes in soil chemistry and the loss of ecological diversity. Especially of concern is Amynthas agrestis and at least one state (Wisconsin) has listed it as a prohibited species.

Question: Where were native earthworms killed by glaciers?
Answer: glaciated areas of North America

Question: Where did most of the current earthworms in glacial areas come from?
Answer: Europe

Question: What type of forests can be hurt by invasive worms?
Answer: Northern hardwood forests
Title: Annelid

Earthworms make a significant contribution to soil fertility. The rear end of the Palolo worm, a marine polychaete that tunnels through coral, detaches in order to spawn at the surface, and the people of Samoa regard these spawning modules as a delicacy. Anglers sometimes find that worms are more effective bait than artificial flies, and worms can be kept for several days in a tin lined with damp moss. Ragworms are commercially important as bait and as food sources for aquaculture, and there have been proposals to farm them in order to reduce over-fishing of their natural populations. Some marine polychaetes' predation on molluscs causes serious losses to fishery and aquaculture operations.

Question: What type of annelid tunnels through coral?
Answer: Palolo worm

Question: What annelid's rear end do Samoans like to eat?
Answer: Palolo worm

Question: What type of bait do experienced anglers prefer?
Answer: spawning modules

Question: What do some polychaetes eat that has been causing problems?
Answer: molluscs

Question: What type of worm have there been proposals to farm?
Answer: Ragworms
Title: Annelid

Accounts of the use of leeches for the medically dubious practise of blood-letting have come from China around 30 AD, India around 200 AD, ancient Rome around 50 AD and later throughout Europe. In the 19th century medical demand for leeches was so high that some areas' stocks were exhausted and other regions imposed restrictions or bans on exports, and Hirudo medicinalis is treated as an endangered species by both IUCN and CITES. More recently leeches have been used to assist in microsurgery, and their saliva has provided anti-inflammatory compounds and several important anticoagulants, one of which also prevents tumors from spreading.

Question: When did leeches begin being used for blood-letting?
Answer: 30 AD

Question: Where did leeches begin being used for blood-letting?
Answer: China

Question: When did Rome begin using leeches?
Answer: 50 AD

Question: When did India begin using leeches?
Answer: 200 AD

Question: Which organizations list Hirudo medicinalis as endangered?
Answer: IUCN and CITES
Title: Annelid

Since annelids are soft-bodied, their fossils are rare. Polychaetes' fossil record consists mainly of the jaws that some species had and the mineralized tubes that some secreted. Some Ediacaran fossils such as Dickinsonia in some ways resemble polychaetes, but the similarities are too vague for these fossils to be classified with confidence. The small shelly fossil Cloudina, from 549 to 542 million years ago, has been classified by some authors as an annelid, but by others as a cnidarian (i.e. in the phylum to which jellyfish and sea anemones belong). Until 2008 the earliest fossils widely accepted as annelids were the polychaetes Canadia and Burgessochaeta, both from Canada's Burgess Shale, formed about 505 million years ago in the early Cambrian. Myoscolex, found in Australia and a little older than the Burgess Shale, was possibly an annelid. However, it lacks some typical annelid features and has features which are not usually found in annelids and some of which are associated with other phyla. Then Simon Conway Morris and John Peel reported Phragmochaeta from Sirius Passet, about 518 million years old, and concluded that it was the oldest annelid known to date. There has been vigorous debate about whether the Burgess Shale fossil Wiwaxia was a mollusc or an annelid. Polychaetes diversified in the early Ordovician, about 488 to 474 million years ago. It is not until the early Ordovician that the first annelid jaws are found, thus the crown-group cannot have appeared before this date and probably appeared somewhat later. By the end of the Carboniferous, about 299 million years ago, fossils of most of the modern mobile polychaete groups had appeared. Many fossil tubes look like those made by modern sessile polychaetes  , but the first tubes clearly produced by polychaetes date from the Jurassic, less than 199 million years ago.

Question: When did Cloudina exist?
Answer: 549 to 542 million years ago

Question: What do some people think Cloudina should be called instead of an annelid?
Answer: cnidarian

Question: How old were the fossils of Canadia and Burgessochaeta found in Canada?
Answer: 505 million years

Question: What era was underway 505 million years ago?
Answer: early Cambrian

Question: Where was Myoscolex found?
Answer: Australia
Title: Annelid

The earliest good evidence for oligochaetes occurs in the Tertiary period, which began 65 million years ago, and it has been suggested that these animals evolved around the same time as flowering plants in the early Cretaceous, from 130 to 90 million years ago. A trace fossil consisting of a convoluted burrow partly filled with small fecal pellets may be evidence that earthworms were present in the early Triassic period from 251 to 245 million years ago. Body fossils going back to the mid Ordovician, from 472 to 461 million years ago, have been tentatively classified as oligochaetes, but these identifications are uncertain and some have been disputed.

Question: When did the Tertiary period begin?
Answer: 65 million years ago

Question: What era did oligochaetes evolve in?
Answer: early Cretaceous

Question: What type of annelid fossils have been found from the mid Ordovician period?
Answer: oligochaetes

Question: When were the earliest annelid fossils found?
Answer: 472 to 461 million years ago
Title: Annelid

Traditionally the annelids have been divided into two major groups, the polychaetes and clitellates. In turn the clitellates were divided into oligochaetes, which include earthworms, and hirudinomorphs, whose best-known members are leeches. For many years there was no clear arrangement of the approximately 80 polychaete families into higher-level groups. In 1997 Greg Rouse and Kristian Fauchald attempted a "first heuristic step in terms of bringing polychaete systematics to an acceptable level of rigour", based on anatomical structures, and divided polychaetes into:

Question: What two groups are annelids traditionally divided among?
Answer: polychaetes and clitellates

Question: What subtype of clitellates contains earthworms?
Answer: oligochaetes

Question: What subtype of clitellates contains leeches?
Answer: hirudinomorphs

Question: How many polychaete families are there?
Answer: approximately 80

Question: When did Greg Rouse begin trying to categorize polychaetes?
Answer: 1997
Title: Annelid

In 2007 Torsten Struck and colleagues compared 3 genes in 81 taxa, of which 9 were outgroups, in other words not considered closely related to annelids but included to give an indication of where the organisms under study are placed on the larger tree of life. For a cross-check the study used an analysis of 11 genes (including the original 3) in 10 taxa. This analysis agreed that clitellates, pogonophorans and echiurans were on various branches of the polychaete family tree. It also concluded that the classification of polychaetes into Scolecida, Canalipalpata and Aciculata was useless, as the members of these alleged groups were scattered all over the family tree derived from comparing the 81 taxa. In addition, it also placed sipunculans, generally regarded at the time as a separate phylum, on another branch of the polychaete tree, and concluded that leeches were a sub-group of oligochaetes rather than their sister-group among the clitellates. Rouse accepted the analyses based on molecular phylogenetics, and their main conclusions are now the scientific consensus, although the details of the annelid family tree remain uncertain.

Question: Who compared annelid genes in 2007?
Answer: Torsten Struck and colleagues

Question: How many annelid genes did Torsten Struck first compare?
Answer: 3

Question: How many annelid genes did Torsten Struck compare for a cross-check?
Answer: 11

Question: What subtypes of polychaetes were useless classifications, according to the 2007 study?
Answer: Scolecida, Canalipalpata and Aciculata

Question: What did Rouse decide leeches were a subgroup of?
Answer: oligochaetes
Title: Annelid

In addition to re-writing the classification of annelids and 3 previously independent phyla, the molecular phylogenetics analyses undermine the emphasis that decades of previous writings placed on the importance of segmentation in the classification of invertebrates. Polychaetes, which these analyses found to be the parent group, have completely segmented bodies, while polychaetes' echiurans and sipunculan offshoots are not segmented and pogonophores are segmented only in the rear parts of their bodies. It now seems that segmentation can appear and disappear much more easily in the course of evolution than was previously thought. The 2007 study also noted that the ladder-like nervous system, which is associated with segmentation, is less universal previously thought in both annelids and arthropods.[n 2]

Question: How many previously-separate phyla did the 2007 study reclassify?
Answer: 3

Question: What did the 2007 study decide was the parent group for annelids?
Answer: Polychaetes

Question: What offshoots of polychaetes are unsegmented?
Answer: echiurans and sipunculan

Question: What offshoots of polychaetes are only segmented in the rear?
Answer: pogonophores

Question: What nervous system structure is less univeral among annelids than was thought before 2007?
Answer: ladder-like
Title: Annelid

Annelids are members of the protostomes, one of the two major superphyla of bilaterian animals – the other is the deuterostomes, which includes vertebrates. Within the protostomes, annelids used to be grouped with arthropods under the super-group Articulata ("jointed animals"), as segmentation is obvious in most members of both phyla. However, the genes that drive segmentation in arthropods do not appear to do the same in annelids. Arthropods and annelids both have close relatives that are unsegmented. It is at least as easy to assume that they evolved segmented bodies independently as it is to assume that the ancestral protostome or bilaterian was segmented and that segmentation disappeared in many descendant phyla. The current view is that annelids are grouped with molluscs, brachiopods and several other phyla that have lophophores (fan-like feeding structures) and/or trochophore larvae as members of Lophotrochozoa. Bryzoa may be the most basal phylum (the one that first became distinctive) within the Lophotrochozoa, and the relationships between the other members are not yet known. Arthropods are now regarded as members of the Ecdysozoa ("animals that molt"), along with some phyla that are unsegmented.

Question: What superphylum are annelids in?
Answer: protostomes

Question: What is the other superphylum besides protostomes?
Answer: deuterostomes

Question: What superphylum are vertebrates in?
Answer: deuterostomes

Question: What does 'Articulata' mean?
Answer: jointed animals

Question: What are lophophores?
Answer: fan-like feeding structures
Title: Annelid

The "Lophotrochozoa" hypothesis is also supported by the fact that many phyla within this group, including annelids, molluscs, nemerteans and flatworms, follow a similar pattern in the fertilized egg's development. When their cells divide after the 4-cell stage, descendants of these 4 cells form a spiral pattern. In these phyla the "fates" of the embryo's cells, in other words the roles their descendants will play in the adult animal, are the same and can be predicted from a very early stage. Hence this development pattern is often described as "spiral determinate cleavage".

Question: Which Lophotrochozoa phyla have similar egg development?
Answer: annelids, molluscs, nemerteans and flatworms

Question: How do the cells of Lophotrochozoa eggs arrange themselves?
Answer: after the 4-cell stage, descendants of these 4 cells form a spiral pattern

Question: What is the Lophotrochozoa spiral egg-cell pattern sometimes called?
Answer: spiral determinate cleavage