query: when do most mammals lose their ability to produce lactase

pos: Lactase persistence Lactase persistence Lactase persistence is the continued activity of the lactase enzyme in adulthood. Since lactase's only function is the digestion of lactose in milk, in most mammal species, the activity of the enzyme is dramatically reduced after weaning. In some human populations, though, lactase persistence has recently evolved as an adaptation to the consumption of nonhuman milk and dairy products beyond infancy. The majority of people around the world remain lactase nonpersistent, and consequently are affected by varying degrees of lactose intolerance as adults. However, not all genetically lactase nonpersistent individuals are noticeably lactose intolerant, and not all lactose

pos: Lactase persistence from negligible to near-ubiquitous frequencies in just 3000 years, suggesting a very strong selective pressure. Some studies also proposed that selection for lactase persistence is not as strong as supposed (soft selective sweep), and that its strength varies a lot depending on particular environmental conditions. Lactose malabsorption is typical for adult mammals, and lactase persistence is a phenomenon likely linked to human interactions in the form of dairying. Most mammals lose the ability to digest lactose once they are old enough to find their own source of nourishment away from their mothers. After weaning, or the transition from being milk-fed

pos: Lactose intolerance genetic differences, not an adaptation to cultural practices. Most mammals normally cease to produce lactase and become lactose intolerant after weaning. The downregulation of lactase expression in mouse could be attributed to the accumulation of DNA methylation in the "Lct" gene and the adjacent "Mcm6" gene. Lactose intolerance Lactose intolerance is a condition in which people have symptoms due to the decreased ability to digest lactose, a sugar found in dairy products. Those affected vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pain, bloating, diarrhea, gas, and nausea. These symptoms typically start

pos: Lactase difference exists in lactase expression in infants, showing that the mutations become increasingly relevant during development. Developmentally regulated DNA-binding proteins may down-regulate transcription or destabilize mRNA transcripts, causing decreased LPH expression after weaning. Lactase Lactase is an enzyme produced by many organisms. It is located in the brush border of the small intestine of humans and other mammals. Lactase is essential to the complete digestion of whole milk; it breaks down lactose, a sugar which gives milk its sweetness. Lacking lactase, a person consuming dairy products may experience the symptoms of lactose intolerance. Lactase can be purchased as a food

pos: Lactase is expressed exclusively by mammalian small intestine enterocytes and in very low levels in the colon during fetal development. Humans are born with high levels of lactase expression. In most of the world’s population, lactase transcription is down-regulated after weaning, resulting in diminished lactase expression in the small intestine, which causes the common symptoms of adult-type hypolactasia, or lactose intolerance. Some population segments exhibit lactase persistence resulting from a mutation that is postulated to have occurred 5,000–10,000 years ago, coinciding with the rise of cattle domestication. This mutation has allowed almost half of the world’s population to metabolize lactose without

neg: Lactase persistence to consuming other types of food, their ability to produce lactase naturally diminishes as it is no longer needed. For example, in the time a piglet in one study aged from five to 18 days, it lost 67% of its lactose absorption ability. While nearly all humans can normally digest lactose for the first 5 to 7 years of their lives, most mammals stop producing lactase much earlier. Cattle can be weaned from their mothers' milk at 6 months to a year of age. Lambs are regularly weaned around 16 weeks old. Such examples suggest that lactase persistence is a

neg: Lactase Lactase Lactase is an enzyme produced by many organisms. It is located in the brush border of the small intestine of humans and other mammals. Lactase is essential to the complete digestion of whole milk; it breaks down lactose, a sugar which gives milk its sweetness. Lacking lactase, a person consuming dairy products may experience the symptoms of lactose intolerance. Lactase can be purchased as a food supplement, and is added to milk to produce "lactose-free" milk products. Lactase (also known as lactase-phlorizin hydrolase, or LPH), a part of the β-galactosidase family of enzymes, is a glycoside hydrolase involved in

neg: Mark G. Thomas "apartheid-like social structure" model to explain the discrepancy between archaeological and genetic estimates of the scale of Anglo-Saxon migration. Thomas has also worked extensively on the evolution of lactase persistence (see Lactose intolerance), the ability of some humans to produce the enzyme lactase throughout their adult life and thus to consume appreciable quantities of fresh milk without the discomforts of lactose malabsorption. In 2004 he led a study to show that most lactase persistent Africans did not have the same mutation causing it as Europeans. In 2007, in collaboration with Joachim Burger's group in Mainz, Germany, he showed that the

neg: Lactose lactic acid by bacteria during ripening. Infant mammals nurse on their mothers to drink milk, which is rich in lactose. The intestinal villi secrete the enzyme lactase (β-D-galactosidase) to digest it. This enzyme cleaves the lactose molecule into its two subunits, the simple sugars glucose and galactose, which can be absorbed. Since lactose occurs mostly in milk, in most mammals, the production of lactase gradually decreases with maturity due to a lack of continuing consumption. Many people with ancestry in Europe, West Asia, South Asia, the Sahel belt in West Africa, East Africa and a few other parts of Central

neg: Milk In some cultures it is common to breastfeed children for three to five years, and the period may be longer. Fresh goats' milk is sometimes substituted for breast milk, which introduces the risk of the child developing electrolyte imbalances, metabolic acidosis, megaloblastic anemia, and a host of allergic reactions. In many cultures, especially in the West, humans continue to consume milk beyond infancy, using the milk of other mammals (especially cattle, goats and sheep) as a food product. Initially, the ability to digest milk was limited to children as adults did not produce lactase, an enzyme necessary for digesting the

neg: Lactase the hydrolysis of the disaccharide lactose into constituent galactose and glucose monomers. Lactase is present predominantly along the brush border membrane of the differentiated enterocytes lining the villi of the small intestine. In humans, lactase is encoded by the LCT gene. Lactase is an enzyme that some people are unable to produce in their small intestine. Without it they can't break down the natural lactose in milk, leaving them with diarrhea, gas and bloating when drinking regular milk. Technology to produce lactose-free milk, ice cream and yogurt was developed by the USDA Agricultural Research Service in 1985. This technology is

neg: Oophorectomy their ovaries. Retaining the ovaries when a hysterectomy is performed is associated with better long-term survival. Hormone therapy for women with oophorectomies performed before age 45 improves the long-term outcome and all-cause mortality rates. Women who have had bilateral oophorectomy surgeries lose most of their ability to produce the hormones estrogen and progesterone, and lose about half of their ability to produce testosterone, and subsequently enter what is known as "surgical menopause" (as opposed to normal menopause, which occurs naturally in women as part of the aging process). In natural menopause the ovaries generally continue to produce low levels of

neg: Lactase persistence populations; selection was detected there as well – though less strong than in European populations. Thus, even if T*13910 may not be causative for lactase persistence, it was selected during human evolutionary history. The other variants were also proved to be under selection. The C*-14010 allele is located on a particularly long stretch of homozygosity (> 2 Mb). The compound allele G*-13915 & C*-3712 was proved to be located on a long stretch of homozygosity (1.1 Mb to 1.3 Mb). The ability to digest lactose is not an evolutionary novelty in human populations. Nearly all mammals begin life with the

neg: Inborn errors of carbohydrate metabolism glycogen metabolism see below. Lactose is a disaccharide sugar composed of galactose and glucose that is found in milk. Lactose can not be absorbed by the intestine and needs to be split in the small intestine into galactose and glucose by the enzyme called lactase; unabsorbed lactose can cause abdominal pain, bloating, diarrhea, gas, and nausea. In most mammals, production of lactase diminishes after infants are weaned from maternal milk. However, 5% to 90% of the human population possess an advantageous autosomal mutation in which lactase production persists after infancy. The geographic distribution of lactase persistence is concordant with areas

neg: Lactose intolerance modify their body’s ability to produce lactase. In societies where lactose intolerance is the norm, it is not considered a condition that requires treatment. However, where dairy is a larger component of the normal diet, a number of efforts may be useful. There are four general principles in dealing with lactose intolerance: avoidance of dietary lactose, substitution to maintain nutrient intake, regulation of calcium intake, and use of enzyme substitute. Regular consumption of dairy food by lactase deficient individuals may also reduce symptoms of intolerance by promoting colonic bacteria adaptation. The primary way of managing the symptoms of lactose intolerance

neg: Lactase persistence ability to digest lactose. This trait is advantageous during the infant stage, because milk serves as the primary source for nutrition. As weaning occurs, and other foods enter the diet, milk is no longer consumed. As a result, the ability to digest lactose no longer provides a distinct fitness advantage. This is evident in examining the mammalian lactase gene ("LCT"), which expression decreases after the weaning stage, resulting in a lowered production of lactase enzymes. When these enzymes are produced in low quantities, lactose non-persistence (LNP) results. The ability to digest fresh milk through adulthood is genetically coded for by

neg: Lactose intolerance geographical region. Lactase persistence is the phenotype associated with various autosomal dominant alleles prolonging the activity of lactase beyond infancy; conversely, lactase nonpersistence is the phenotype associated with primary lactase deficiency. Among mammals, lactase persistence is unique to humans—it evolved relatively recently (in the last 10,000 years) among some populations, and the majority of people worldwide remain lactase nonpersistent. For this reason, lactase persistence is of some interest to the fields of anthropology, human genetics, and archaeology, which typically use the genetically derived persistence/non-persistence terminology. The rise of dairy and producing dairy related products from cow milk alone, varies across

neg: Mammalian reproduction Mammalian reproduction Most mammals are viviparous, giving birth to live young. However, the five species of monotreme, the platypuses and the echidnas, lay eggs. The monotremes have a sex determination system different from that of most other mammals. In particular, the sex chromosomes of a platypus are more like those of a chicken than those of a therian mammal. The mammary glands of mammals are specialized to produce milk, a liquid used by newborns as their primary source of nutrition. The monotremes branched early from other mammals and do not have the nipples seen in most mammals, but they do

neg: Hydrolysis and fructose. Invertase is a sucrase used industrially for the hydrolysis of sucrose to so-called invert sugar. Lactase is essential for digestive hydrolysis of lactose in milk; many adult humans do not produce lactase and cannot digest the lactose in milk. The hydrolysis of polysaccharides to soluble sugars is called "saccharification". Malt made from barley is used as a source of β-amylase to break down starch into the disaccharide maltose, which can be used by yeast to produce beer. Other amylase enzymes may convert starch to glucose or to oligosaccharides. Cellulose is first hydrolyzed to cellobiose by cellulase and then

neg: Golden poison frog of nerve cells, but the frog has special sodium channels the poison cannot harm. Since easily purchased foods are not rich in the alkaloids required to produce batrachotoxins, captive frogs do not produce toxins and they eventually lose their toxicity in captivity. In fact, many hobbyists and herpetologists have reported that most dart frogs will not consume ants at all in captivity, though ants constitute the larger portion of their diets in the wild, likely due to the unavailability of the natural prey species of ants to captive frog keepers. Though all poison frogs lose their toxicity when deprived of

neg: Lactase persistence of South Africa. Multiple studies indicate that the presence of the two phenotypes "lactase persistent" (derived phenotype) and "lactase nonpersistent (hypolactasia)" is genetically programmed, and that lactase persistence is not necessarily conditioned by the consumption of lactose after the suckling period. The lactase persistent phenotype involves high mRNA expression, high lactase activity, and thus the ability to digest lactose, while the lactase nonpersistent phenotype involves low mRNA expression and low lactase activity. The enzyme lactase is encoded by the gene "LCT". Hypolactasia is known to be recessively and autosomally inherited, which means that individuals with the nonpersistent phenotype are homozygous

neg: Lactase symptoms. Studies have linked the occurrence of lactase persistence to two different single-nucleotide polymorphisms about 14 and 22 kilobases upstream of the 5’-end of the LPH gene. Both mutations, C→T at position -13910 and G→ A at position -22018, have been independently linked to lactase persistence. The lactase promoter is 150 base pairs long and is located just upstream of the site of transcription initiation. The sequence is highly conserved in mammals, suggesting that critical cis-transcriptional regulators are located nearby. Cdx-2, HNF-1α, and GATA have been identified as transcription factors. Studies of hypolactasia onset have demonstrated that despite polymorphisms, little

neg: Lactase persistence intolerant individuals have the lactase nonpersistence genotype. The distribution of the lactase persistence phenotype, or the ability to digest lactose into adulthood, is not homogeneous in the world. Lactase persistence-frequencies are highly variable. In Europe, the distribution of the lactase persistence phenotype is clinal, with frequencies ranging from 15–54% in the south-east to 89–96% in the north-west. For example, only 17% of Greeks and 14% of Sardinians are predicted to possess this phenotype, while around 80% of Finns and Hungarians and 100% of Irish people are predicted to be lactase persistent. High frequencies of lactase persistence are also found in

neg: Mammal the presence of epipubic bones in all non-placental mammals prevents the expansion of the torso needed for full pregnancy. Even non-placental eutherians probably reproduced this way. The placentals give birth to relatively complete and developed young, usually after long gestation periods. They get their name from the [[placenta]], which connects the developing fetus to the uterine wall to allow nutrient uptake. The mammary glands of mammals are specialized to produce milk, the primary source of nutrition for newborns. The monotremes branched early from other mammals and do not have the [[nipple]]s seen in most mammals, but they do have mammary

neg: Quorum sensing its competitive binding to LsrR. Glyceraldehyde 3-phosphate has also been shown to inhibit the "lsr" operon through cAMP-CAPK-mediated inhibition. This explains why, when grown with glucose, "E. coli" will lose the ability to internalize AI-2 (because of catabolite repression). When grown normally, AI-2 presence is transient. "E. coli" and "Salmonella enterica" do not produce AHL signals commonly found in other Gram-negative bacteria. However, they have a receptor that detects AHLs from other bacteria and change their gene expression in accordance with the presence of other "quorate" populations of Gram-negative bacteria. "Salmonella" encodes a LuxR homolog, SdiA, but does not encode

neg: Crocodilia their olfactory system for hunting. When above water, crocodiles enhance their ability to detect volatile odorants by gular pumping, a rhythmic movement of the floor of the pharynx. The well-developed trigeminal nerve allows them to detect vibrations in the water (such as those made by potential prey). The tongue cannot move freely but is held in place by a folded membrane. While the brain of a crocodilian is fairly small, it is capable of greater learning than most reptiles. Though they lack the vocal folds of mammals and the syrinx of birds, crocodilians can produce vocalisations by vibrating three flaps

neg: Underwater diving can survive for at least thirty minutes provided they do not drown. The ability to stay afloat declines substantially after about ten minutes as the chilled muscles lose strength and co-ordination. The diving reflex is a response to immersion that overrides the basic homeostatic reflexes. It optimises respiration by preferentially distributing oxygen stores to the heart and brain, which allows extended periods underwater. It is exhibited strongly in aquatic mammals (seals, otters, dolphins and muskrats), and also exists in other mammals, including humans. Diving birds, such as penguins, have a similar diving reflex. The diving reflex is triggered by chilling

neg: Polybia emaciata There can be hundreds of workers in the nest that do the majority of work foraging for food and resources. Since they are a swarm founding species even building new nests is mostly done by workers. Sometimes, there are intermediates in "Polybia emaciata "which are workers that used to be queens. It is likely that at the foundation of new nests they lost dominance competitions and lost their ability to produce eggs. Since they lost the dominance competition and there is limited space for the queens they lose their ability to reproduce. For "Polybia emaciata" to survive and form new

neg: Aquatic mammal ocean vessels and large marine mammals. Habitat degradation also threatens marine mammals and their ability to find and catch food. Noise pollution, for example, may adversely affect echolocating mammals, and the ongoing effects of global warming degrades arctic environments. Mammals evolved on land, so all aquatic and semiaquatic mammals have brought many terrestrial adaptations into the waters. They do not breathe underwater as fish do, so their respiratory systems had to protect the body from the surrounding water; valvular nostrils and an intranarial larynx exclude water while breathing and swallowing. To navigate and detect prey in murky and turbid waters,

neg: Microbat is the extended articulation of the ventral portion of the tympanic bones and the proximal end of the stylohyal bone that bends around it to make this connection. The human vocalization system has been extensively studied, and as a result, is the most well understood compared to any other mammal. It has been instrumental in increasing our understanding of the vocalization systems of other mammals, including microbats. In the past, the human vocalization system was believed to be unique when compared to any of the other mammal vocalization system's, because of their ability to produce complex language and song. However,

neg: Cellulose e.g. in an ionic liquid. Most mammals have limited ability to digest dietary fiber such as cellulose. Some ruminants like cows and sheep contain certain symbiotic anaerobic bacteria (like "Cellulomonas") in the flora of the rumen, and these bacteria produce enzymes called cellulases that help the microorganism to digest cellulose; the breakdown products are then used by the bacteria for proliferation. The bacterial mass is later digested by the ruminant in its digestive system (stomach and small intestine). Horses use cellulose in their diet by fermentation in their hindgut via symbiotic bacteria which produce cellulase to digest cellulose. Similarly, some

neg: Lactase persistence tribes over the age of 30. According to the gene-culture coevolution hypothesis, the ability to digest lactose into adulthood (lactase persistence) became advantageous to humans after the invention of animal husbandry and the domestication of animal species that could provide a consistent source of milk. Hunter-gatherer populations before the Neolithic revolution were overwhelmingly lactose intolerant, as are modern hunter-gatherers. Genetic studies suggest that the oldest mutations associated with lactase persistence only reached appreciable levels in human populations in the last 10,000 years. This correlates with the beginning of animal domestication, which occurred during the Neolithic transition. Therefore, lactase persistence is

neg: Gout produce uricase, which breaks down uric acid. Humans and other great apes do not have this ability, thus gout is common. Other animals with uricase include fish, amphibians, and most non primate mammals. The "Tyrannosaurus rex" specimen known as "Sue" is believed to have suffered from gout. A number of new medications are under study for treating gout, including anakinra, canakinumab, and rilonacept. Canakinumab may result in better outcomes than a low dose of a steroid, but costs five thousand times more. A recombinant uricase enzyme (rasburicase) is available but its use is limited, as it triggers an immune response.

neg: Effects of global warming on marine mammals a result of increasing temperatures. When the ice melts, polar bears lose their habitat and food sources. Although polar bears have been known to eat more than 80 species of animals, most of their diet consists of seals, which are also endangered by global warming. There have been an increasing number of polar bear drownings because they become exhausted by having to swim farther to find ice or prey. Effects of global warming on marine mammals The effect of global warming on marine mammals is a growing concern. Many of the effects of global warming are currently unknown due to

neg: Domestic rabbit Zealand), and 6–7 months for large breeds (e.g., Flemish Giant). Bucks usually require more time to sexually mature than does, and they normally reach adult sperm counts at 6–7 months. Rabbits, like all mammals, produce milk for their young. Female rabbits have six to eight nipples and produce milk for four weeks after birthing. Rabbit milk is relatively high in fat, as a percentage by mass. While most species produce approximately 5% milk fat, rabbits produce 12%. The excerpted table below compares milk characteristics among mammals. Disease is rare when rabbits are raised in sanitary conditions and provided with adequate

neg: White (horse) melanocytes...but from a deficiency and/or alteration of the structure of tyrosinase in melanocytes which are otherwise normal." This definition of albinism in mice - the inability to make tyrosinase - is extended to other mammals. While mammals derive their pigments only from melanins, fish, reptiles and birds rely on a number of pigments apart from melanins: carotenoids, porphyrins, psittacofulvins, pterins, etc. Most commonly, reptiles with a condition homologous to human OCA1A retain their reddish and orangish hues. As a result, birds and reptiles without the ability to manufacture tyrosinase are more accurately described as "amelanistic." Horses do not have non-melanin

neg: Bolognese dog lose large amounts of fur as many other breeds do. However, they do eventually lose and replace individual hairs, similar to human hair growth cycles. Each hair grows from a hair follicle, which has a three phase cycle, as do most mammals. These cycles are: "anagen", growth of normal hair; "catagen" growth slows, and hair shaft thins; "telegen", hair growth stops, follicle rests, and old hair fall off—is shed. At the end of the telegen phase, the follicle begins the cycle again. The length of time of the growing and shedding cycle varies by age and other factors. There is

neg: Stachybotrys chartarum does not compete well with other molds. It is only rarely found in nature, and seldom encounters the kind of large-scale living environment occasionally produced by human habitation (i.e., large amounts of cellulose, large temperature fluctuations, low nitrogen, no other molds, no sunlight, and ample constant humidity). The spores are only released into the ambient air when the mold is manually disturbed, particularly when wet. It is considered an uncommon contaminant of most indoor air. Not all strains of "S. chartarum" produce mycotoxins, and under certain conditions some of these lose the ability to produce such toxins over time; the

neg: Pinniped even been observed successfully hunting on their own in Lake Saimaa, likely relying on their vibrissae to gain sensory information and catch prey. Unlike terrestrial mammals, such as rodents, pinnipeds do not move their vibrissae over an object when examining it but instead extend their moveable whiskers and keep them in the same position. By holding their vibrissae steady, pinnipeds are able to maximize their detection ability. The vibrissae of phocids are undulated and wavy while otariid and walrus vibrissae are smooth. Research is ongoing to determine the function, if any, of these shapes on detection ability. The vibrissa's angle

neg: Plant the vascular plants, perennials include both evergreens that keep their leaves the entire year, and deciduous plants that lose their leaves for some part of it. In temperate and boreal climates, they generally lose their leaves during the winter; many tropical plants lose their leaves during the dry season. The growth rate of plants is extremely variable. Some mosses grow less than 0.001 millimeters per hour (mm/h), while most trees grow 0.025-0.250 mm/h. Some climbing species, such as kudzu, which do not need to produce thick supportive tissue, may grow up to 12.5 mm/h. Plants protect themselves from frost and

neg: Marine mammal other species, such as the North Atlantic right whale, are critically endangered. Other than hunting, marine mammals can be killed as bycatch from fisheries, where they become entangled in fixed netting and drown or starve. Increased ocean traffic causes collisions between fast ocean vessels and large marine mammals. Habitat degradation also threatens marine mammals and their ability to find and catch food. Noise pollution, for example, may adversely affect echolocating mammals, and the ongoing effects of global warming degrade arctic environments. Marine mammals form a diverse group of 129 species that rely on the ocean for their existence. They do

neg: Lactose Africa maintain lactase production into adulthood. In many of these areas, milk from mammals such as cattle, goats, and sheep is used as a large source of food. Hence, it was in these regions that genes for lifelong lactase production first evolved. The genes of adult lactose tolerance have evolved independently in various ethnic groups. By descent, more than 70% of western Europeans can drink milk as adults, compared with less than 30% of people from areas of Africa, eastern and south-eastern Asia and Oceania. In people who are lactose intolerant, lactose is not broken down and provides food for

neg: Lactase persistence some places in Sub-Saharan Africa and in the Middle East. But the most common situation is intermediate to low lactase persistence: intermediate (11 to 32%) in Central Asia, low (<=5%) in Native Americans, East Asians, most Chinese populations and some African populations. In Africa, the distribution of lactase persistence is "patchy": high variations of frequency are observed in neighbouring populations, for example between Beja and Nilotes from Sudan. This makes the study of lactase persistence distribution more difficult. High percentages of lactase persistence phenotype are found in traditionally pastoralist populations like Fulani and Bedouins. It is absent in the Bantu

neg: Morganucodon a toothless stage at infancy strongly suggests that "Morganucodon" raised its young by lactation; indeed, it may have been among the very first animals to do so. The molars in the adult had a series of raised humps and edges that fit into each other, allowing for efficient chewing. However, unlike the situation in most later mammals, the upper and lower molars did not occlude properly when they first met; as they wore against each other, however, their shapes were modified by wear to produce a precise fit. "Morganucodon" is the type genus for the order Morganucodonta, a group of

neg: Regeneration (biology) reparative regenerative ability across the group. Examples of physiological regeneration in mammals include epithelial renewal (e.g., skin and intestinal tract), red blood cell replacement, antler regeneration and hair cycling. Male deer lose their antlers annually during the months of January to April then through regeneration are able to regrow them as an example of physiological regeneration. A deer antler is the only appendage of a mammal that can be regrown every year. While reparative regeneration is a rare phenomenon in mammals, it does occur. A well-documented example is regeneration of the digit tip distal to the nail bed. Reparative regeneration

neg: Sensory substitution non-invasive prosthetic devices for sensory impaired people". The first sensory substitution system was developed by Bach-y-Rita et al. as a means of brain plasticity in congenitally blind individuals. After this historic invention, sensory substitution has been the basis of many studies investigating perceptive and cognitive neuroscience. Since then, sensory substitution has contributed to the study of brain function, human cognition and rehabilitation. When a person becomes blind or deaf they generally do not lose the ability to hear or see; they simply lose their ability to transmit the sensory signals from the periphery (retina for visions and cochlea for hearing)

neg: Enterocyte Enterocyte Enterocytes, or intestinal absorptive cells, are simple columnar epithelial cells found in the small intestine. A glycocalyx surface coat contains digestive enzymes. Microvilli on the apical surface increase surface area for the digestion and transport of molecules from the intestinal lumen. The cells also have a secretory role. The major functions of enterocytes include: Dietary fructose intolerance occurs when there is a deficiency in the amount of fructose carrier. Lactose intolerance is the most common problem of carbohydrate digestion and occurs when the human body doesn't produce a sufficient amount of lactase (a disaccharidase) enzyme to break down the

neg: Polygyny in animals Instead, it is much more common for polygynous mating to happen. Polygynous structures (excluding leks) are estimated to occur in up to 90% of mammals. Polygyny in birds occurs infrequently when compared to mammals, as monogamy is most commonly observed. Evolutionarily speaking, polygyny in birds might have evolved because many females do not require male support to care for their offspring. Because females do not need extra help raising their nests, males can afford to invest in multiple females. Nonetheless, male parental care is often found in many polygynous territorial bird species, leading to female competition for male assistance. Most

neg: Divergent evolution in animals insects are believed to be a result of needing the ultrasonic hearing that tympanal ears provide in order to hear predators in the dark. Non-nocturnal insects - that do not need to fear nocturnal predators - are often found to lack these tympanal ears. Animals undergo divergent evolution for a number of reasons. Predators or their absence, changes in the environment, and the time at which certain animals are most active are chief among them. A lack of predators – predatory birds and mammals - for cliff-side nest residing kittiwake caused that particular group of kittiwake to lose their ancestral

neg: Sociology of health and illness order to care for the sick parents, the children have to take on more responsibility by working to produce an income. Not only do the children lose their parents but they also lose their childhood as well. Having to provide care for their parents, the children also miss out on an education which increases the risk of teen pregnancy and people affected with HIV. The most efficient way to diminish the orphan epidemic is prevention: preventing children from acquiring HIV from their mothers at birth, as well as educating them on the disease as they grow older. Also, educating adults

neg: Glucose chains there are amylases (named after amylose, a component of starch), cellulases (named after cellulose), chitinases (named after chitin) and more. Furthermore, for the cleavage of disaccharides, there are maltase, lactase, sucrase, trehalase and others. In humans, about 70 genes are known that code for glycosidases. They have functions in the digestion and degradation of glycogen, sphingolipids, mucopolysaccharides and poly(ADP-ribose). Humans do not produce cellulases, chitinases and trehalases, but the bacteria in the gut flora do. In order to get into or out of cell membranes of cells and membranes of cell compartments, glucose requires special transport proteins from the

neg: Lactase persistence and received the two copies of a low lactase-activity allele (the ancestral allele) from their parents, who may be homozygous or at least heterozygous for the allele. Only one high-activity allele is required to be lactase persistent. Lactase persistence behaves as a dominant trait because half levels of lactase activity are sufficient to show significant digestion of lactose. Cis-acting transcriptional silence of the lactase gene is responsible for the hypolactasia phenotype. Furthermore, studies show that only eight cases were found where the parents of a child with lactase persistence were both hypolactasic. While a variety of genetic, as well as

neg: Guinea pig stronger than a guinea pig and may cause intentional or inadvertent injury. The guinea pig's natural diet is grass; their molars are particularly suited for grinding plant matter and grow continuously throughout their life. Most mammals that graze are large and have a long digestive tract; guinea pigs have much longer colons than most rodents, but they must also supplement their diet by eating their feces (coprophagy) . However, they do not consume all their feces indiscriminately, but produce special soft pellets, called cecotropes (or caecal pellets), which recycle B vitamins, fiber, and bacteria required for proper digestion. The cecotropes

neg: Reproductive system are some notable differences between the non-human mammals and humans. For instance, most male mammals have a penis which is stored internally until erect, and most have a penis bone or baculum. Additionally, males of most species do not remain continually sexually fertile as humans do. Like humans, most groups of mammals have descended testicles found within a scrotum, however, others have descended testicles that rest on the ventral body wall, and a few groups of mammals, such as elephants, have undescended testicles found deep within their body cavities near their kidneys. The reproductive system of marsupials is unique in

neg: Rhadinovirus virus exits the host cell by nuclear egress, and budding. Human and mammals serve as the natural host. Transmission routes are sexual, contact, and saliva. Group: dsDNA Rhadinoviruses are unique because they have mastered the ability to pirate cellular genes from their host cells and incorporate them into their genomes. For example, most rhadinoviruses have a copy of the cyclin gene, which regulates the ability of the cell to divide. These viruses tend to cause tumors when infection occurs outside of their native hosts or in the case of KSHV, in humans when the host is immunosuppressed due to AIDS,

neg: Insect farming entomophagy include: Cattle use 12 times the amount of feed that crickets do to produce an equal amount of protein. Crickets also only use a quarter of the feed of sheep and one half the amount of feed given to swine and chicken to produce an equivalent amount of protein. Crickets require only two pounds of feed to produce one pound of finished product. Much of this efficiency is a result of crickets being ectothermic, as in they get their heat from the environment instead of having to expend energy to create their own body heat like typical mammals do.

neg: Projectile use by non-human organisms up to about 50 cm. They are believed to do this because during the brooding season, when penguins are sitting on their nests, they avoid leaving their nests and thereby leaving their eggs open to predation and thus to maintain a clean nest they evolved the ability to project their feces. Among mammals, skunks can eject a noxious fluid from glands near their anus. It is not only foul smelling, but can cause skin irritation and, if it gets in the eyes, temporary blindness. When it feels threatened a camel will bring up their stomach contents, along with saliva, and

neg: Lactose intolerance of lactose intolerance in adults. Lactose intolerance is classified according to its causes as: Primary hypolactasia, or primary lactase deficiency, is genetic, only affects adults, and is caused by the absence of a lactase persistence allele. In individuals without the lactase persistence allele, less lactase is produced by the body over time, leading to hypolactasia in adulthood. The frequency of lactase persistence, which allows lactose tolerance, varies enormously worldwide, with the highest prevalence in Northwestern Europe, declines across southern Europe and the Middle East and is low in Asia and most of Africa, although it is common in pastoralist populations

neg: Polyomaviridae Stewart and Bernice Eddy, after whom it was once called "SE polyoma". The term "polyoma" refers to the viruses' ability to produce multiple (poly-) tumors (-oma) under certain conditions. The name has been criticized as a "meatless linguistic sandwich" ("meatless" because both morphemes in "polyoma" are affixes) giving little insight into the viruses' biology; in fact, subsequent research has found that most polyomaviruses rarely cause clinically significant disease in their host organisms under natural conditions. Dozens of polyomaviruses have been identified and sequenced as of 2016, infecting mainly birds and mammals. Two polyomaviruses are known to infect fish, the black

neg: Lactase persistence polymorphisms – SNPs) have been associated with lactase expression. They are all located in a region of the gene "MCM6" upstream of "LCT". This region is considered as an enhancer region for the transcription of "LCT". The first identified genetic variant associated with lactase persistence is C/T*−13910. The ancestral allele is C and the derived allele – associated with lactase persistence – is T. In the same study, another variant was found to also correlate with the phenotype in most of the cases: G*/A-22018. Other alleles associated with lactase persistence have been identified: G/C*-14010, C/G*-13907, and T/G*-13915. This variant is

neg: Plant algae. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria. Their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic or mycotrophic and may lose the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although asexual reproduction is also common. There are about 320 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants (see the table below). Green plants provide a substantial proportion

neg: Lactose intolerance depending on the severity of these symptoms. "Lactose malabsorption" refers to the physiological concomitant of lactase deficiency (i.e., the body does not have sufficient lactase capacity to digest the amount of lactose ingested). Hypolactasia (lactase deficiency) is distinguished from alactasia (total lack of lactase), a rare congenital defect. Lactose intolerance is not an allergy, because it is not an immune response, but rather a sensitivity to dairy caused by lactase deficiency. Milk allergy, occurring in only 4% of the population, is a separate condition, with distinct symptoms that occur when the presence of milk proteins trigger an immune reaction. The

neg: Polistes dominula social insects, which may cause increased aggression and work inefficiencies. Also, if the colony can produce a new queen, it could be slow to produce eggs. After queen loss, replacement queens do not mate in the 12 days following queen removal and few had mature eggs in their ovaries. After a month, most replacement queens develop ovaries and mate. Nest growth decreases with colonies that lose their queen, which can be expected if increased dominance behavior interfered with other essential behaviors or if the new queen is not competent at egg laying. Among queenless colonies of "P. dominula", individuals demonstrated

neg: Ant exhaustion. The female worker ants do not have wings and reproductive females lose their wings after their mating flights in order to begin their colonies. Therefore, unlike their wasp ancestors, most ants travel by walking. Some species are capable of leaping. For example, Jerdon's jumping ant ("Harpegnathos saltator") is able to jump by synchronising the action of its mid and hind pairs of legs. There are several species of gliding ant including "Cephalotes atratus"; this may be a common trait among most arboreal ants. Ants with this ability are able to control the direction of their descent while falling. Other

neg: Stress fracture and lose their ability to absorb shock. As the bones now experience larger stresses, this increases the risk of fracture. Previous stress fractures have been identified as a risk factor. X-rays usually do not show evidence of new stress fractures, but can be used 3 weeks after onset of pain when the bone begins to remodel. A CT scan, MRI, or 3-phase bone scan may be more effective for early diagnosis. MRI appears to be the most accurate test. Altering the biomechanics of training and training schedules may reduce the prevalence of stress fractures. Orthotic insoles have been found to

neg: Apocrine sweat gland glands, which produce ear wax; and the mammary glands, which produce milk. The rest of the body is covered by eccrine sweat glands. Most non-primate mammals, however, have apocrine sweat glands over the greater part of their body. Domestic animals such as dogs and cats have apocrine glands at each hair follicle but eccrine glands only in foot pads and snout. Their apocrine glands, like those in humans, produce an odorless, oily, opaque secretion that gains its characteristic odor upon bacterial decomposition. Eccrine glands on their paws increase friction and prevent them from slipping when fleeing from danger. The apocrine

neg: Thermogenic plant Thermogenic plant Thermogenic plants have the ability to raise their temperature above that of the surrounding air. Heat is generated in the mitochondria, as a secondary process of cellular respiration called thermogenesis. Alternative oxidase and uncoupling proteins similar to those found in mammals enable the process, which is still poorly understood. Botanists are not completely sure why thermogenic plants generate large amounts of excess heat, but most agree that it has something to do with increasing pollination rates. The most widely accepted theory states that the endogenous heat helps in spreading chemicals that attract pollinators to the plant. For example,

neg: Allele age due to its role in HIV resistance. Many adults are lactose intolerant because their bodies cease production of the enzyme lactase post childhood. However, mutations in the promoter region of the lactase gene (LCT) result in the continued production of lactase throughout adulthood in certain African populations, a condition known as lactase persistence. A study conducted by Sarah Tishkoff and her team shows that the mutation for lactase persistence has been under positive selection since its recent appearance approximately 3,000 to 7,000 years ago. These dates are consistent with the rise of cattle domestication and pastoralist lifestyles in these regions,

neg: Animal husbandry a semi-closed organic system. Although all mammals produce milk to nourish their young, the cow is predominantly used throughout the world to produce milk and milk products for human consumption. Other animals used to a lesser extent for this purpose include sheep, goats, camels, buffaloes, yaks, reindeer, horses and donkeys. All these animals have been domesticated over the centuries, being bred for such desirable characteristics as fecundity, productivity, docility and the ability to thrive under the prevailing conditions. Whereas in the past, cattle had multiple functions, modern dairy cow breeding has resulted in specialised Holstein Friesian-type animals that produce large

neg: The Hallmarks of Cancer way cells prevent over-division is that normal cells will also stop dividing when the cells fill up the space they are in and touch other cells; known as contact inhibition. Cancer cells do not have contact inhibition, and so will continue to grow and divide, regardless of their surroundings. Cells have the ability to 'self-destruct'; a process known as apoptosis. This is required for organisms to grow and develop properly, for maintaining tissues of the body, and is also initiated when a cell is damaged or infected. Cancer cells, however, lose this ability; even though cells may become grossly abnormal,

neg: Vitamin C undergoes enolization to form ascorbic acid. Some mammals have lost the ability to synthesize vitamin C, including simians and tarsiers, which together make up one of two major primate suborders, Haplorrhini. This group includes humans. The other more primitive primates (Strepsirrhini) have the ability to make vitamin C. Synthesis does not occur in most bats nor in species in the rodent family Caviidae, that includes guinea pigs and capybaras, but does occur in other rodents, including rats and mice. Reptiles and older orders of birds make ascorbic acid in their kidneys. Recent orders of birds and most mammals make ascorbic

neg: Orthoreovirus with σ1, interspersed around the capsid. It has been proposed that λ2 is involved in replication due to its placement at the fivefold axes and its ability to interact with λ3 in solution. σ1, a filamentous trimer extruding from the outer capsid, is responsible for cell attachment by interacting with sialic acid and other entry receptors. μ1 and σ3 are both involved in the attachment and thus entry of the virus via receptor-mediated endocytosis involving the formation of clathrin-coated pits. The only orthoreovirus to not produce syncytia, mammalian orthoreoviruses have the capability of infecting all mammals, but do not cause

neg: Roar (vocalization) Roar (vocalization) A roar is a type of animal vocalization consisting of both a low fundamental frequency (pitch) and low formant frequency. Many mammals have the ability to produce roars and other roar-like vocalizations. These include big cats, gorillas, elephants, some bovids, howler monkeys, bears, red deer, some pinnipeds and hammer-headed bats. The ability to roar has an anatomical basis, often involving modifications to the larynx and hyoid bone and enlarged internal air spaces for low-frequency acoustic resonance. While roaring, animals may stretch out their necks and elevate their heads to increase the space for resonance. Though usually airborne, some

neg: Olfaction volatile organic compounds. Parasites such as dodder make use of this in locating their preferred hosts and locking on to them. The emission of volatile compounds is detected when foliage is browsed by animals. Threatened plants are then able to take defensive chemical measures, such as moving tannin compounds to their foliage. (See Plant perception). The importance and sensitivity of smell varies among different organisms; most mammals have a good sense of smell, whereas most birds do not, except the tubenoses (e.g., petrels and albatrosses), certain species of vultures, and the kiwis. Among mammals, it is well developed in the

neg: Speech-generating device additional sounds that may be important for the user such as laughing or whistling. Moreover, Digitized SGDs is that they provide a degree of normalcy both for the patient and for their families when they lose their ability to speak on their own. A major disadvantage of using only recorded speech is that users are unable to produce novel messages; they are limited to the messages pre-recorded into the device. Depending on the device, there may be a limit to the length of the recordings. SGDs that use synthesized speech apply the phonetic rules of the language to translate the

neg: Lyckantropen Themes still procreate an impact. Ulver formidably accomplish this with apparent ease and grace, and also illustrate an unfamiliar way to approach arranging the soundtrack apart from the film. The best thing about Ulver is their ability to adapt. They can use any given situation or feeling and produce a whole record without overplaying or showboating, they just get their point across and finish in silence. When you watch the film and lose your mind in the soundtrack, that’s the best experience for you to begin to understand what the film is actually doing.” Rating the soundtrack 9/10, Alvin Wee, writing

neg: Dog whelk into water, as it does not have the adaptation possessed by many upper shore species which would allow it to produce uric acid for excretion without loss of water. When kept emersed for seven days at a temperature of 18°C, 100% of dog whelks die, in contrast to many periwinkle species which can lose even more water than the dog whelk (i.e. more than 37% of their total body mass) but survive as a result of their ability to excrete toxic waste products more efficiently. Its adaptations include a modified radula (a toothed chitinous structure) to bore holes in the

neg: Inborn errors of carbohydrate metabolism of high milk intake. Lactase non-persistence is common in tropical and subtropical countries. Individuals with lactase non-persistency may experience nausea, bloating and diarrhea after ingesting dairy. Galactosemia, the inability to metabolize galactose in liver cells, is the most common monogenic disorder of carbohydrate metabolism, affecting 1 in every 55,000 newborns. When galactose in the body is not broken down, it accumulates in tissues. The most common signs are failure to thrive, hepatic insufficiency, cataracts and developmental delay. Long term disabilities include poor growth, mental retardation, and ovarian failure in females. Galactosemia is caused by mutations in the gene that makes

neg: Phonological development to speak and thus have no production vocabulary. So clearly, comprehension vocabulary develops before production vocabulary. Even though children do not produce their first words until they are approximately 12 months old, the ability to produce speech sounds starts to develop at a much younger age. Stark (1980) distinguishes five stages of early speech development: These earliest vocalizations include crying and vegetative sounds such as breathing, sucking or sneezing. For these vegetative sounds, infants’ vocal cords vibrate and air passes through their vocal apparatus, thus familiarizing infants with processes involved in later speech production. Infants produce cooing sounds when they

neg: Domestic pig the latter appear limited to the snout and dorsonasal areas. Pigs, however, like other "hairless" mammals (e.g. elephants, rhinos, and mole-rats), do not use thermal sweat glands in cooling. Pigs are also less able than many other mammals to dissipate heat from wet mucous membranes in the mouth through panting. Their thermoneutral zone is . At higher temperatures, pigs lose heat by wallowing in mud or water via evaporative cooling; although it has been suggested that wallowing may serve other functions, such as protection from sunburn, ecto-parasite control, and scent-marking. Pigs are one of four known mammalian species which possess

neg: Diurnality shown in studies done on small nocturnal mice in a laboratory setting. When they were placed under a combination of enough cold and hunger stress, they converted to diurnality through temporal niche switching, which was expected. Another similar study that involved energetically challenging small mammals showed that diurnality is most beneficial when the animal has a sheltered location to rest in, reducing heat loss. Both studies concluded that nocturnal mammals do change their activity patterns to be more diurnal when energetically stressed (due to heat loss and limited food availability), but only when predation is also limited, meaning the risks

neg: Intestinal gland duodenum, jejunum, and ileum, and in the large intestine (colon), where they are sometimes called "colonic crypts". Intestinal glands of the small intestine contain a base of replicating stem cells, Paneth cells of the innate immune system, and goblet cells, which produce mucus. In the colon, crypts do not have Paneth cells. The enterocytes in the small intestinal mucosa contain digestive enzymes that digest specific foods while they are being absorbed through the epithelium. These enzymes include peptidase, sucrase, maltase, lactase and intestinal lipase. This is in contrast to the gastric glands of the stomach where chief cells secrete pepsinogen.

neg: Nudge theory behave in a particular way, by altering the environment so that automatic cognitive processes are triggered to favour the desired outcome. An individual’s behaviour is not always in alignment with their intentions (termed a value-action gap). It is common knowledge that humans are not fully rational beings; that is, people will often do something that is not in their own self interest, even when they are aware that their actions are not in their best interest. As an example, when hungry, dieters often under-estimate their ability to lose weight, and their intentions to eat healthy can be temporarily weakened until

neg: Lactose intolerance in Asian Americans, African Americans, Mexican Americans, and Native Americans. Analysis of the DNA of 94 ancient skeletons in Europe and Russia concluded that the mutation for lactose tolerance appeared about 4,300 years ago and spread throughout the European population. Some human populations have developed lactase persistence, in which lactase production continues into adulthood probably as a response to the benefits of being able to digest milk from farm animals. Some have argued that this links intolerance to natural selection favoring lactase-persistent individuals, but it is also consistent with a physiological response to decrease lactase production when it is not

neg: Digestion glucose molecules) that can be absorbed by the small intestine. Lactase is an enzyme that breaks down the disaccharide lactose to its component parts, glucose and galactose. Glucose and galactose can be absorbed by the small intestine. Approximately 65 percent of the adult population produce only small amounts of lactase and are unable to eat unfermented milk-based foods. This is commonly known as lactose intolerance. Lactose intolerance varies widely by ethnic heritage; more than 90 percent of peoples of east Asian descent are lactose intolerant, in contrast to about 5 percent of people of northern European descent. Sucrase is an

neg: Spotted sandgrouse may reach over 50 °C, the birds are inactive and have the ability to increase their thermal insulation when the air temperature exceeds their body temperatures. At very high temperatures they also resort to gular fluttering and gaping to cool themselves. At night, several flocks coalesce and fly off into the rocky desert far away from any vegetation. Each bird scrapes itself a shallow sleeping hollow by moving from side to side. There are no jerboas or other small mammals in these barren wastes so foxes and jackals do not roam there at night and the birds are safe. In

neg: Ordinal numerical competence function can create a difference in how we experience certain types of arithmetic. Approximate arithmetic can be experienced as intuitive and exact arithmetic experienced as recalled knowledge. The conclusions from behavioral research and brain-imaging research are supported by observations of patients with injuries to certain parts of the brain. People with left parietal injuries can lose the ability to understand quantities of things, but keep at least some ability to do exact arithmetic, such as multiplication. People with left-hemisphere brain damage can lose the ability to do exact arithmetic, but keep a sense of quantity, including the ability to compare

neg: Antimetabolite and subsequent incorporation of these biomolecules into nucleic acids, inhibits their normal tumor cell function and triggers apoptosis, or the cell death process. Because of this mode of action, most antimetabolites have high cell cycle specificity and can target arrest of cancer cell DNA replication. Antimetabolites may also be antibiotics, such as sulfanilamide drugs, which inhibit dihydrofolate synthesis in bacteria by competing with para-aminobenzoic acid (PABA). PABA is needed in enzymatic reactions that produce folic acid, which acts as a coenzyme in the synthesis of purines and pyrimidines, the building-blocks of DNA. Mammals do not synthesize their own folic acid

neg: Allotheria gave milk to feed their young like monotremes do. This is a feature of all non-placental mammals. When he first identified Allotheria in 1880, Othniel Marsh regarded this group as an order within Marsupialia. However, in 1997 McKenna and Bell classified Allotheria as an infraclass. Zofia Kielan-Jaworowska, Richard L. Cifelli, and Zhe-Xi Luo, "Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure" (New York: Columbia University Press, 2004), 249. Allotheria Allotheria (meaning "other beasts", from the Greek , '–other and , '–wild animal) is an extinct branch of successful Mesozoic mammals. The most important characteristic was the presence of

neg: Chipmunk an important vector for dispersal of the spores of subterranean sporocarps (truffles) which have co-evolved with these and other mycophagous mammals and thus lost the ability to disperse their spores through the air. Chipmunks construct expansive burrows which can be more than in length with several well-concealed entrances. The sleeping quarters are kept clean as shells and feces are stored in refuse tunnels. The eastern chipmunk hibernates in the winter, while western chipmunks do not, relying on the stores in their burrows. Chipmunks play an important role as prey for various predatory mammals and birds but are also opportunistic predators

neg: Staphylococcus = < 15 mm zone of inhibition). Further biochemical testing is needed to identify to the species level. When these bacteria divide, they do so along two axes, so form clumps of bacteria. This is as opposed to streptococci, which divide along one axis, so form chains ("strep" meaning twisted or pliant). One of the most important phenotypical features used in the classification of staphylococci is their ability to produce coagulase, an enzyme that causes blood clot formation. Seven species are currently recognised as being coagulase-positive: "S. aureus", "S. delphini", "S. hyicus", "S. intermedius", "S. lutrae", "S. pseudintermedius", and "S.

neg: Fresh water to fresh water to live. Some terrestrial mammals, especially desert rodents appear to survive without drinking but they do generate water through the metabolism of cereal seeds and they also have mechanisms to conserve water to the maximum degree. Fresh water creates a hypotonic environment for aquatic organisms. This is problematic for some organisms with pervious skins or with gill membranes, whose cell membranes may burst if excess water is not excreted. Some protists accomplish this using contractile vacuoles, while freshwater fish excrete excess water via the kidney. Although most aquatic organisms have a limited ability to regulate their osmotic

neg: Thermogenic plant water vapor to disperse its scent — that of rotting meat — above the cold air that settles over it at night in its natural habitat. Thermogenic plant Thermogenic plants have the ability to raise their temperature above that of the surrounding air. Heat is generated in the mitochondria, as a secondary process of cellular respiration called thermogenesis. Alternative oxidase and uncoupling proteins similar to those found in mammals enable the process, which is still poorly understood. Botanists are not completely sure why thermogenic plants generate large amounts of excess heat, but most agree that it has something to do

neg: African forest elephant Male African forest elephants tend to be solitary and only associate with other elephants during the mating season. Males have a dominance hierarchy based on size. Since the Loxodonta cyclotis species is newly recognized, there is little to no concrete literature on communication and perception. For these mammals, hearing and smell are the most important senses they possess due to the fact that they do not have good eyesight. They can recognize and hear vibrations through the ground and can detect food sources with their sense of smell. Elephants are also an Arrhythmic species, meaning they have the ability to

neg: Grid cell the hippocampus, because it continues to appear in animals whose hippocampus has been inactivated by an agonist of GABA. Many species of mammals can keep track of spatial location even in the absence of visual, auditory, olfactory, or tactile cues, by integrating their movements—the ability to do this is referred to in the literature as path integration. A number of theoretical models have explored mechanisms by which path integration could be performed by neural networks. In most models, such as those of Samsonovich and McNaughton (1997) or Burak and Fiete (2009), the principal ingredients are (1) an internal representation of

neg: Motion perception mammals can keep track of spatial location even in the absence of visual, auditory, olfactory, or tactile cues, by integrating their movements—the ability to do this is referred to in the literature as path integration. A number of theoretical models have explored mechanisms by which path integration could be performed by neural networks. In most models, such as those of Samsonovich and McNaughton (1997) or Burak and Fiete (2009), the principal ingredients are (1) an internal representation of position, (2) internal representations of the speed and direction of movement, and (3) a mechanism for shifting the encoded position by the

neg: Effect of spaceflight on the human body minutes at a time without fainting. This is due in part to changes in the autonomic regulation of blood pressure and the loss of plasma volume. Although this effect becomes worse the longer the time spent in space, as yet all individuals have returned to normal within at most a few weeks of landing. In space, astronauts lose fluid volume—including up to 22% of their blood volume. Because it has less blood to pump, the heart will atrophy. A weakened heart results in low blood pressure and can produce a problem with "orthostatic tolerance", or the body's ability to send

neg: Space medicine with greater brain changes. In space, astronauts lose fluid volume—including up to 22% of their blood volume. Because it has less blood to pump, the heart will atrophy. A weakened heart results in low blood pressure and can produce a problem with “orthostatic tolerance,” or the body’s ability to send enough oxygen to the brain without fainting or becoming dizzy. "Under the effects of the earth's gravity, blood and other body fluids are pulled towards the lower body. When gravity is taken away or reduced during space exploration, the blood tends to collect in the upper body instead, resulting in

neg: Paul Broca same area as had been affected in Leborgne’s brain. This finding concluded that a specific area controlled our ability to produce meaningful sounds, and when it is affected, one can lose their capability to communicate. For the next two years, Broca went on to find autopsy evidence from 12 more cases in support of the localization of articulated language. Broca published his findings from the autopsies of the 12 patients in his paper, “Localization of Speech in the Third Left Frontal Cultivation” in 1865. His work inspired others to perform careful autopsies win the aim of linking more brain regions

neg: Island tameness Island tameness Island tameness is the tendency of many populations and species of animals living on isolated islands to lose their wariness of potential predators, particularly of large animals. The term is partly synonymous with "ecological naïvete", which also has a wider meaning referring to the loss of defensive behaviors and adaptations needed to deal with these "new" predators. Species retain such wariness of predators that exist in their environment, for example a Hawaiian goose retains its wariness of hawks, but lose such behaviors associated with mammals or other predators not found in their historical range. The most famous example