rajpurkar/squad huggingface dataset:
Title: Bird

Avialans diversified into a wide variety of forms during the Cretaceous Period. Many groups retained primitive characteristics, such as clawed wings and teeth, though the latter were lost independently in a number of avialan groups, including modern birds (Aves). While the earliest forms, such as Archaeopteryx and Jeholornis, retained the long bony tails of their ancestors, the tails of more advanced avialans were shortened with the advent of the pygostyle bone in the group Pygostylia. In the late Cretaceous, around 95 million years ago, the ancestor of all modern birds also evolved a better sense of smell.

Question: During which time period did avialans diversify into a wide variety of forms?
Answer: Cretaceous Period

Question: Which forms retained the long bony tails of their ancestors?
Answer: Archaeopteryx and Jeholornis

Question: When did the ancestor of all modern birds evolve a better sense of smell?
Answer: late Cretaceous

Question: How long ago was the late Cretaceous period?
Answer: around 95 million years ago
Title: Bird

The first large, diverse lineage of short-tailed avialans to evolve were the enantiornithes, or "opposite birds", so named because the construction of their shoulder bones was in reverse to that of modern birds. Enantiornithes occupied a wide array of ecological niches, from sand-probing shorebirds and fish-eaters to tree-dwelling forms and seed-eaters. While they were the dominant group of avialans during the Cretaceous period, enantiornithes became extinct along with many other dinosaur groups at the end of the Mesozoic era.

Question: What were the first large, diverse lineage of short-tailed avialans to evolve?
Answer: enantiornithes

Question: Because of the construction of their shoulder bones, what were the enantiornithes called?
Answer: opposite birds

Question: What was the dominant group of avialans during the Cretaceous period?
Answer: enantiornithes

Question: When did enantiornithes become extinct?
Answer: end of the Mesozoic era
Title: Bird

Many species of the second major avialan lineage to diversify, the Euornithes (meaning "true birds", because they include the ancestors of modern birds), were semi-aquatic and specialized in eating fish and other small aquatic organisms. Unlike the enantiornithes, which dominated land-based and arboreal habitats, most early euornithes lacked perching adaptations and seem to have included shorebird-like species, waders, and swimming and diving species. The later included the superficially gull-like Ichthyornis, the Hesperornithiformes, which became so well adapted to hunting fish in marine environments that they lost the ability to fly and became primarily aquatic. The early euornithes also saw the development of many traits associated with modern birds, like strongly keeled breastbones, toothless, beaked portions of their jaws (though most non-avian euornithes retained teeth in other parts of the jaws). Euornithes also included the first avialans to develop true pygostyle and a fully mobile fan of tail feathers, which may have replaced the "hind wing" as the primary mode of aerial maneuverability and braking in flight.

Question: What group became the first avialans to develop true pygostyle and a fully mobile fan of tail feathers?
Answer: Euornithes

Question: What does Euornithes mean?
Answer: true birds

Question: Why does Euornithes mean "true birds?"
Answer: because they include the ancestors of modern birds

Question: What may have replaced the "hind wing" as the primary mode of aerial maneuverability?
Answer: fully mobile fan of tail feathers
Title: Bird

All modern birds lie within the crown group Aves (alternately Neornithes), which has two subdivisions: the Palaeognathae, which includes the flightless ratites (such as the ostriches) and the weak-flying tinamous, and the extremely diverse Neognathae, containing all other birds. These two subdivisions are often given the rank of superorder, although Livezey and Zusi assigned them "cohort" rank. Depending on the taxonomic viewpoint, the number of known living bird species varies anywhere from 9,800 to 10,050.

Question: All modern birds lie within which crown group?
Answer: Aves

Question: What is another name for Aves?
Answer: Neornithes

Question: The two subdivisions of what group include Palaeognathae and Neognathae?
Answer: Aves

Question: What is the number range of living bird species?
Answer: 9,800 to 10,050
Title: Bird

The earliest divergence within the Neognathes was that of the Galloanserae, the superorder containing the Anseriformes (ducks, geese, swans and screamers) and the Galliformes (the pheasants, grouse, and their allies, together with the mound builders and the guans and their allies). The earliest fossil remains of true birds come from the possible galliform Austinornis lentus, dated to about 85 million years ago, but the dates for the actual splits are much debated by scientists. The Aves are agreed to have evolved in the Cretaceous, and the split between the Galloanseri from other Neognathes occurred before the Cretaceous–Paleogene extinction event, but there are different opinions about whether the radiation of the remaining Neognathes occurred before or after the extinction of the other dinosaurs. This disagreement is in part caused by a divergence in the evidence; molecular dating suggests a Cretaceous radiation, while fossil evidence supports a Cenozoic radiation. Attempts to reconcile the molecular and fossil evidence have proved controversial, but recent results show that all the extant groups of birds originated from only a small handful of species that survived the Cretaceous–Paleogene extinction.

Question: What was the earliest divergence within the Neognathes?
Answer: Galloanserae

Question: What is the superorder containing the Anseriformes?
Answer: Galloanserae

Question: Ducks, geese, swans and screamers are part of which group?
Answer: Anseriformes

Question: The pheasants, grouse and their allies form which group?
Answer: Galliformes
Title: Bird

The classification of birds is a contentious issue. Sibley and Ahlquist's Phylogeny and Classification of Birds (1990) is a landmark work on the classification of birds, although it is frequently debated and constantly revised. Most evidence seems to suggest the assignment of orders is accurate, but scientists disagree about the relationships between the orders themselves; evidence from modern bird anatomy, fossils and DNA have all been brought to bear on the problem, but no strong consensus has emerged. More recently, new fossil and molecular evidence is providing an increasingly clear picture of the evolution of modern bird orders. The most recent effort is drawn above and is based on whole genome sequencing of 48 representative species.

Question: Sibley and Ahlquist' Phylogeny and Classification of Birds is a landmark work on the classification of what animals?
Answer: birds

Question: What do scientists disagree about?
Answer: relationships between the orders themselves

Question: What do scientists tend to agree on?
Answer: the assignment of orders is accurate
Title: Bird

Birds live and breed in most terrestrial habitats and on all seven continents, reaching their southern extreme in the snow petrel's breeding colonies up to 440 kilometres (270 mi) inland in Antarctica. The highest bird diversity occurs in tropical regions. It was earlier thought that this high diversity was the result of higher speciation rates in the tropics, however recent studies found higher speciation rates in the high latitudes that were offset by greater extinction rates than in the tropics. Several families of birds have adapted to life both on the world's oceans and in them, with some seabird species coming ashore only to breed and some penguins have been recorded diving up to 300 metres (980 ft).

Question: Birds live on how many continents?
Answer: seven

Question: Highest bird diversity occurs in which regions?
Answer: tropical

Question: Some penguins have been recording diving up to how many feet?
Answer: 980

Question: Some seabird species only come ashore for what purpose?
Answer: to breed
Title: Bird

Many bird species have established breeding populations in areas to which they have been introduced by humans. Some of these introductions have been deliberate; the ring-necked pheasant, for example, has been introduced around the world as a game bird. Others have been accidental, such as the establishment of wild monk parakeets in several North American cities after their escape from captivity. Some species, including cattle egret, yellow-headed caracara and galah, have spread naturally far beyond their original ranges as agricultural practices created suitable new habitat.

Question: The ring-necked pheasant has been introduced as what kind of bird?
Answer: game bird

Question: Why have some species spread naturally far beyond their original ranges?
Answer: agricultural practices created suitable new habitat

Question: Where have many birds established breeding populations?
Answer: in areas to which they have been introduced by humans
Title: Bird

The skeleton consists of very lightweight bones. They have large air-filled cavities (called pneumatic cavities) which connect with the respiratory system. The skull bones in adults are fused and do not show cranial sutures. The orbits are large and separated by a bony septum. The spine has cervical, thoracic, lumbar and caudal regions with the number of cervical (neck) vertebrae highly variable and especially flexible, but movement is reduced in the anterior thoracic vertebrae and absent in the later vertebrae. The last few are fused with the pelvis to form the synsacrum. The ribs are flattened and the sternum is keeled for the attachment of flight muscles except in the flightless bird orders. The forelimbs are modified into wings.

Question: What consists of very lightweight bones?
Answer: The skeleton

Question: What does the skeleton consist of?
Answer: very lightweight bones

Question: What are pneumatic cavities?
Answer: large air-filled cavities

Question: What are large air-filled cavities that connect to the respiratory system?
Answer: pneumatic cavities

Question: What is formed when vertebrae are fused with the pelvis?
Answer: synsacrum
Title: Bird

Like the reptiles, birds are primarily uricotelic, that is, their kidneys extract nitrogenous waste from their bloodstream and excrete it as uric acid instead of urea or ammonia through the ureters into the intestine. Birds do not have a urinary bladder or external urethral opening and (with exception of the ostrich) uric acid is excreted along with feces as a semisolid waste. However, birds such as hummingbirds can be facultatively ammonotelic, excreting most of the nitrogenous wastes as ammonia. They also excrete creatine, rather than creatinine like mammals. This material, as well as the output of the intestines, emerges from the bird's cloaca. The cloaca is a multi-purpose opening: waste is expelled through it, most birds mate by joining cloaca, and females lay eggs from it. In addition, many species of birds regurgitate pellets. Males within Palaeognathae (with the exception of the kiwis), the Anseriformes (with the exception of screamers), and in rudimentary forms in Galliformes (but fully developed in Cracidae) possess a penis, which is never present in Neoaves. The length is thought to be related to sperm competition. When not copulating, it is hidden within the proctodeum compartment within the cloaca, just inside the vent. The digestive system of birds is unique, with a crop for storage and a gizzard that contains swallowed stones for grinding food to compensate for the lack of teeth. Most birds are highly adapted for rapid digestion to aid with flight. Some migratory birds have adapted to use protein from many parts of their bodies, including protein from the intestines, as additional energy during migration.

Question: What is it called when a bird's kidneys extract nitrogenous waste from their bloodstream and secrete it as uric acid?
Answer: uricotelic

Question: Which bid has a urinary bladder or external urethral opening?
Answer: ostrich

Question: What is a multi-purpose opening on birds?
Answer: cloaca

Question: How do most birds mate?
Answer: by joining cloaca

Question: What aids birds with flight?
Answer: rapid digestion
Title: Bird

Birds have one of the most complex respiratory systems of all animal groups. Upon inhalation, 75% of the fresh air bypasses the lungs and flows directly into a posterior air sac which extends from the lungs and connects with air spaces in the bones and fills them with air. The other 25% of the air goes directly into the lungs. When the bird exhales, the used air flows out of the lung and the stored fresh air from the posterior air sac is simultaneously forced into the lungs. Thus, a bird's lungs receive a constant supply of fresh air during both inhalation and exhalation. Sound production is achieved using the syrinx, a muscular chamber incorporating multiple tympanic membranes which diverges from the lower end of the trachea; the trachea being elongated in some species, increasing the volume of vocalizations and the perception of the bird's size.

Question: Upon inhalation, what percentage of fresh air bypasses the lungs and flows directly into a posterior air sac?
Answer: 75%

Question: Where does the other 25 percent of fresh air go?
Answer: directly into the lungs

Question: What is the syrinx?
Answer: a muscular chamber incorporating multiple tympanic membranes

Question: Sound production is achieved using what muscular chamber?
Answer: syrinx

Question: Which animal has one of the most complex respiratory system of all animal groups?
Answer: Birds
Title: Bird

The avian circulatory system is driven by a four-chambered, myogenic heart contained in a fibrous pericardial sac. This pericardial sac is filled with a serous fluid for lubrication. The heart itself is divided into a right and left half, each with an atrium and ventricle. The atrium and ventricles of each side are separated by atrioventricular valves which prevent back flow from one chamber to the next during contraction. Being myogenic, the heart's pace is maintained by pacemaker cells found in the sinoatrial node, located on the right atrium. The sinoatrial node uses calcium to cause a depolarizing signal transduction pathway from the atrium through right and left atrioventricular bundle which communicates contraction to the ventricles. The avian heart also consists of muscular arches that are made up of thick bundles of muscular layers. Much like a mammalian heart, the avian heart is composed of endocardial, myocardial and epicardial layers. The atrium walls tend to be thinner than the ventricle walls, due to the intense ventricular contraction used to pump oxygenated blood throughout the body. Avian hearts are generally larger than mammalian hearts when compared to body mass. This adaptation allows more blood to be pumped to meet the high metabolic need associated with flight.

Question: The avian circulatory system is driven by what?
Answer: four-chambered, myogenic heart

Question: Where is the heart contained in the avian circulatory system?
Answer: fibrous pericardial sac

Question: What lubricates the pericardial sac?
Answer: serous fluid

Question: Why are Avian hearts larger than mammalian hearts when compared to body mass?
Answer: allows more blood to be pumped
Title: Bird

Birds have a very efficient system for diffusing oxygen into the blood; birds have a ten times greater surface area to gas exchange volume than mammals. As a result, birds have more blood in their capillaries per unit of volume of lung than a mammal. The arteries are composed of thick elastic muscles to withstand the pressure of the ventricular constriction, and become more rigid as they move away from the heart. Blood moves through the arteries, which undergo vasoconstriction, and into arterioles which act as a transportation system to distribute primarily oxygen as well as nutrients to all tissues of the body. As the arterioles move away from the heart and into individual organs and tissues they are further divided to increase surface area and slow blood flow. Travelling through the arterioles blood moves into the capillaries where gas exchange can occur. Capillaries are organized into capillary beds in tissues, it is here that blood exchanges oxygen for carbon dioxide waste. In the capillary beds blood flow is slowed to allow maximum diffusion of oxygen into the tissues. Once the blood has become deoxygenated it travels through venules then veins and back to the heart. Veins, unlike arteries, are thin and rigid as they do not need to withstand extreme pressure. As blood travels through the venules to the veins a funneling occurs called vasodilation bringing blood back to the heart. Once the blood reaches the heart it moves first into the right atrium, then the right ventricle to be pumped through the lungs for further gas exchange of carbon dioxide waste for oxygen. Oxygenated blood then flows from the lungs through the left atrium to the left ventricle where it is pumped out to the body.

Question: Why are birds' arteries composed of thick elastic muscles?
Answer: to withstand the pressure of the ventricular constriction

Question: What moves through the arteries?
Answer: Blood

Question: What is organized into capillary beds in tissues?
Answer: Capillaries

Question: What is the funneling that occurs that brings blood back to the heart?
Answer: vasodilation
Title: Bird

The nervous system is large relative to the bird's size. The most developed part of the brain is the one that controls the flight-related functions, while the cerebellum coordinates movement and the cerebrum controls behaviour patterns, navigation, mating and nest building. Most birds have a poor sense of smell with notable exceptions including kiwis, New World vultures and tubenoses. The avian visual system is usually highly developed. Water birds have special flexible lenses, allowing accommodation for vision in air and water. Some species also have dual fovea. Birds are tetrachromatic, possessing ultraviolet (UV) sensitive cone cells in the eye as well as green, red and blue ones. This allows them to perceive ultraviolet light, which is involved in courtship. Birds have specialized light-sensing cells deep in their brains that respond to light without input from eyes or other sensory neurons. These photo-receptive cells in the hypothalamus are involved in detecting the longer days of spring, and thus regulate breeding activities.

Question: Which bird system is large relative to a bird's size?
Answer: nervous system

Question: What is tetrachromatic?
Answer: possessing ultraviolet (UV) sensitive cone cells in the eye as well as green, red and blue ones

Question: Why do birds need to perceive ultraviolet light?
Answer: courtship

Question: What regulates breeding activities?
Answer: photo-receptive cells in
Title: Bird

Many birds show plumage patterns in ultraviolet that are invisible to the human eye; some birds whose sexes appear similar to the naked eye are distinguished by the presence of ultraviolet reflective patches on their feathers. Male blue tits have an ultraviolet reflective crown patch which is displayed in courtship by posturing and raising of their nape feathers. Ultraviolet light is also used in foraging—kestrels have been shown to search for prey by detecting the UV reflective urine trail marks left on the ground by rodents. The eyelids of a bird are not used in blinking. Instead the eye is lubricated by the nictitating membrane, a third eyelid that moves horizontally. The nictitating membrane also covers the eye and acts as a contact lens in many aquatic birds. The bird retina has a fan shaped blood supply system called the pecten. Most birds cannot move their eyes, although there are exceptions, such as the great cormorant. Birds with eyes on the sides of their heads have a wide visual field, while birds with eyes on the front of their heads, such as owls, have binocular vision and can estimate the depth of field. The avian ear lacks external pinnae but is covered by feathers, although in some birds, such as the Asio, Bubo and Otus owls, these feathers form tufts which resemble ears. The inner ear has a cochlea, but it is not spiral as in mammals.

Question: What covers the eye and acts as a contact lens in many aquatic birds?
Answer: nictitating membrane

Question: What is the fan shaped blood supply system in a bird's retina?
Answer: pecten

Question: Which birds have a wide visual field?
Answer: Birds with eyes on the sides of their heads

Question: What kind of vision do owls have?
Answer: binocular vision

Question: Where is a bird's cochlea located?
Answer: inner ear
Title: Bird

A dearth of field observations limit our knowledge, but intraspecific conflicts are known to sometimes result in injury or death. The screamers (Anhimidae), some jacanas (Jacana, Hydrophasianus), the spur-winged goose (Plectropterus), the torrent duck (Merganetta) and nine species of lapwing (Vanellus) use a sharp spur on the wing as a weapon. The steamer ducks (Tachyeres), geese and swans (Anserinae), the solitaire (Pezophaps), sheathbills (Chionis), some guans (Crax) and stone curlews (Burhinus) use a bony knob on the alular metacarpal to punch and hammer opponents. The jacanas Actophilornis and Irediparra have an expanded, blade-like radius. The extinct Xenicibis was unique in having an elongate forelimb and massive hand which likely functioned in combat or defence as a jointed club or flail. Swans, for instance, may strike with the bony spurs and bite when defending eggs or young.

Question: What is known to sometimes result in injury or death?
Answer: intraspecific conflicts

Question: What is another name for steamer ducks?
Answer: Tachyeres

Question: What is another name for Anhimidae?
Answer: screamers

Question: What do stone curlews use to punch and hammer opponents?
Answer: bony knob on the alular metacarpal
Title: Bird

Feathers are a feature characteristic of birds (though also present in some dinosaurs not currently considered to be true birds). They facilitate flight, provide insulation that aids in thermoregulation, and are used in display, camouflage, and signaling. There are several types of feathers, each serving its own set of purposes. Feathers are epidermal growths attached to the skin and arise only in specific tracts of skin called pterylae. The distribution pattern of these feather tracts (pterylosis) is used in taxonomy and systematics. The arrangement and appearance of feathers on the body, called plumage, may vary within species by age, social status, and sex.

Question: What is a feature characteristic of birds?
Answer: Feathers

Question: What feature of a bird facilitate flight?
Answer: Feathers

Question: What is pterylae?
Answer: specific tracts of skin