You're such a dishonest israelite. Most monkey species are omnivores, making herbivorous apes the exception to the rule rather than the rule.
2 weeks ago
Anonymous
>Most monkey species are omnivores,
Insofar as they will consume insects and eggs etc, yes, correct. Very few monkeys hunt & eat meat.
The point is that their forward facing eyes are beneficial for things other than hunting prey.
2 weeks ago
Anonymous
>Insects and eggs aren't prey
You're really fricking dumb, dude.
2 weeks ago
Anonymous
Front facing eyes give brachiating frugivores the depth perception necessary to maneuverer through the branches and canopy they call home.
Despite being exclusively frugivorous or herbivorous, these monkey species haven't begun to develop side-facing eyes for greater peripheral vision to evade predation.
So even when you don't hunt or eat meat, front-facing eyes have benefits.
I don't happen to subscribe to the insane delusion that humans are ancestrally vegan or plant-based. There's no evidence for it. We need meat for optimum health. But you shouldn't argue the point with faulty logic like "front facing eyes durr".
Humans are primates, and all primates have front facing eyes, no matter what their diet is. Therefore, arguments about our "natural" or "optimum" diet ought not to make reference to our ocular morphology.
2 weeks ago
Anonymous
Front facing eyes give brachiating frugivores the depth perception necessary to maneuverer through the branches and canopy they call home.
Despite being exclusively frugivorous or herbivorous, these monkey species haven't begun to develop side-facing eyes for greater peripheral vision to evade predation.
So even when you don't hunt or eat meat, front-facing eyes have benefits.
I don't happen to subscribe to the insane delusion that humans are ancestrally vegan or plant-based. There's no evidence for it. We need meat for optimum health. But you shouldn't argue the point with faulty logic like "front facing eyes durr".
Humans are primates, and all primates have front facing eyes, no matter what their diet is. Therefore, arguments about our "natural" or "optimum" diet ought not to make reference to our ocular morphology.
With that in mind, here is the two sentences that ACTUALLY destroyed the "humans are vegans by nature" theory. >In humans, more than half (56%) of the total gut volume is found in the small intestine whereas all apes have by far the greatest total gut volume (>45%) in the colon. In addition, the overall size of the human gut in relation to body size is small in comparison to that of apes.
Comparative anatomy can tell you a lot about the differences between related species. Picrel. Imagine picrel had no legend - you would probably still correctly identify which of the species typically had the most animal foods in its diet.
2 weeks ago
Anonymous
https://www.sciencedirect.com/science/article/pii/S0022316623025518 > A brief examination of the dietary behavior of extant great apes illustrates the important role meat eating may have played in permitting members of what became the human lineage to overcome the energetic constraints imposed by increasing body size in the hominoid lineage without a concomitant increase in dietary quality. >In plant-eating mammals, an increase in body size has far different dietary implications than an increase in body size in strongly carnivorous mammals. A pure carnivore, such as a cat, can increase in size over evolutionary time with no decrease in dietary quality. This can be seen by comparing, for example, the foods of a lynx with those of a tiger; the only difference is the size of the prey. This situation does not prevail in the case of plant-eating mammals. >As plant-eating mammals increase in body size, invariably their dietary quality must decrease, as can be seen by comparing, for example, the foods of a tiny forest antelope with those of an elephant. Demment (33) and Demment and Van Soest (34) have postulated that changing body size is a mechanism for differentiating the feeding requirements of herbivores and note that with larger body size, the fiber content of the diet invariably rises (i.e., dietary quality decreases).
2 weeks ago
Anonymous
>As discussed, there is general consensus that extant hominoids, both apes and humans, come from a strongly plant-eating ancestry. Presumably selection for increased body size in gorillas and orangutans was initially associated with environmental conditions in which higher quality plant foods, for whatever reason—competition with monkeys, seasonal shortages, or other factors—simply were not available and/or accessible in sufficient quantity throughout the year. Or, conversely, it could also have been the case that lower quality plant foods were abundant and could easily and efficiently be used by a larger-bodied hominoid. >Increasing body size over evolutionary time would permit these apes to survive on lower quality plant foods than otherwise would be possible, and to utilize plant sources that would not support smaller primates, thus getting around the postulated competition with monkeys. Large body size appears to be the single most important adaptation to diet shown by both gorillas and orangutans >However, this increase in body size and dependence on lower quality plant foods carries with it certain negative consequences, namely, the diminution of some traits generally viewed as highly characteristic of higher primates, and in particular, a high degree of mobility and sociality. Neither gorillas nor orangutans are as active, agile and behaviorally complex as members of the genus Pan nor do they show the high degree of sociality that characterizes chimpanzees.
2 weeks ago
Anonymous
>In fact, orangutans are the only extant anthropoids that live solitarily, a social regression apparently dictated by their large size and the distribution patterns of their wild plant foods. Due to features of their almost exclusively plant-based diet in combination with their pattern of gut kinetics, energy input in these two great apes may often be sufficiently limited such that nonessential behaviors are not favored by selection—in other words, orangutans and gorillas may not have sufficient “extra” energy to be more active and social >Gorillas and orangutans illustrate what can occur in the hominoid lineage on an evolutionary trajectory of increased body size and lowered dietary quality. What happens in a hominoid if, despite environmental pressures, a species is able to maintain dietary quality while continuing to feed largely on plant foods? Extant chimpanzees and bonobos illustrate this dietary strategy. They eat a high quality diet composed largely of ripe fruits, and supplement this basic fruit diet with select protein-rich young leaves, buds and flowers as well as some animal matter, largely invertebrates but occasionally smaller vertebrates >The Pan ancestor may have been somewhat smaller than extant chimpanzees and perhaps not such an extreme ripe fruit specialist. By becoming larger in body size over evolutionary time—male chimpanzees weigh some 49 kg and females 41 kg —and increasingly specialized on ripe fruits, which are an unusually high energy food, chimpanzees and bonobos persist today as highly active and social apes. Somewhat larger body size permits chimpanzees to reap some of the metabolic benefits discussed above for the other two great apes. It also ensures access to fruit crops (chimps can displace smaller-bodied competitors from fruiting trees) and offers some degree of predator protection when traveling on the ground (chimpanzees generally travel through the forest on the ground, climbing into fruiting trees to feed)
2 weeks ago
Anonymous
>Because the foods on which chimpanzees specialize (ripe fruits) are high in energy, one might wonder why they retain a capacious hindgut. Why don't gut proportions of extant chimpanzees more closely approximate those of modern humans? As hominoids, chimpanzees have both a small cecum and a slow turnover rate of ingesta. They also must be able to take in sufficient plant material each day to meet or almost meet their protein and other required nutrients. Woody seeds, pectic substances, cellulose and hemicellulose are inevitable components of fruit eating. The large colon enables chimps to retain such plant materials for sufficient time to allow gut bacteria to ferment pectin and some dietary fiber (22). Volatile fatty acids produced in fermentation provide chimpanzees with energy and such energy may be essential to their survival during periods of the year when ripe fruit is in short supply. >We now have two examples. One is that of extant hominoids (gorillas and orangutans) that represents an evolutionary trajectory associated with enlarged body size and lowered dietary quality. The other example is that of extant hominoids of somewhat smaller body size (chimpanzees), and an evolutionary trajectory predicated on “holding the line” regarding dietary quality. Early humans appear to represent an example of the only other possibility—that is, what can happen in the hominoid line when, for whatever reason, energy needs gradually begin to increase and dietary quality does not decline or remain constant but actually improves.
2 weeks ago
Anonymous
>Imagine a potential human ancestor weighing 35–45 kg (the size range of some Australopithecus and Paranthropus species), living in Africa during the Plio-Pleistocene. This prehuman ancestor has a gut anatomy and a pattern of digestive kinetics similar to those of extant apes. Furthermore, it has the typical hominoid diet of fruits and seeds supplemented with young leaves, flowers and other plant parts as well as occasional animal matter. A climatic change occurs such that areas of wet lowland rainforest gradually became both cooler and drier (36). As a result of this climatic shift and its effects on vegetation, higher quality plant foods become more difficult to procure (more seasonal and more diffuse in space as well as less diverse). >Taking the path of least resistance and turning to lower quality plant foods, a dietary approach that actually was adapted by some hominid species in this environment during the Plio-Pleistocene (i.e., Paranthropus spp.) was not successful. Fossil evidence shows that by ∼1.2 mya, all such species, popularly referred to as the “robust australopithecines,” became extinct (11). If a hominoid in this environment is to persist through time as a mobile, active and social species, all data suggest it must at least hold the line on dietary quality regardless of these environmental changes. But if higher quality plant foods, particularly fruits, are becoming more scattered and seasonal, at the very least this implies higher travel costs to obtain a sufficiency. So even though our hypothetical ancestor is, for the time being, still the same size and eating the same quality diet, the energetic costs associated with the procurement of this diet are increasing.
2 weeks ago
Anonymous
>This hypothetical ancestor will have to eat more of its normal plant foods per unit time or become more efficient at extracting nutrients from these foods just to “stay in place” dietarily. Furthermore, conflicting demands are gradually being placed on its hominoid digestive tract. If this ancestor is to process sufficient plant material each day to satisfy its nutrient as well as energy requirements, the standard large hominoid colon would prove useful; but if it has increasing energetic demands with no decrease in dietary quality, evidence from studies of voles and birds suggest that such pressures will increase the size of the small intestine and decrease the size of the colon. This ancestral species thus appears to be approaching an evolutionary crossroads in terms of diet. >The role played by animal source foods >Options for diet in any mammal are limited. Food has to consist either of plant or animal matter or a mix of both, and it has to supply all nutrients (or their precursors) regarded as essential for that particular animal's needs. What spells the difference between animal species in terms of diet are the types and proportions of foods from each of these two basic dietary categories that each species can most efficiently exploit. In terms of gut anatomy and digestive kinetics, meat and other ASF, at least up to some maximum percentage of diet, pose no digestive problems for a hominoid. > In captivity, for example, boned meat (raw beef and cooked chicken) was so well digested by common chimpanzees that it typically produced no visible residue in feces. > Data suggest that most monkeys and all great apes can digest ASF, and that many primates appear to relish them (38, 39). But ASF are not eaten in quantity by most wild primates (39), largely because such foods are rare, generally small in size and difficult to procure, particularly in the tropical forest canopy.
2 weeks ago
Anonymous
>This is not to say that ASF are not important, indeed essential, dietary components, for many primate species (39). But because only small amounts typically can be secured each day, anthropoids typically fill up on higher quality plant foods and supplement this plant-based diet with as much ASF as can be secured without undue cost or effort. >The earliest humans (members of the genus Homo) appear to have evolved in a woodland-savanna environment in Africa where ripe fruits and other high quality plant sources showed strong seasonal fluctuation. Fossil evidence suggests there may have been three or more different species of homosexual living in Africa approximately two million years ago (11). These homosexual species differed morphologically from other hominids (e.g., Australopithecus, Paranthropus) in that their check tooth size was smaller and somewhat more refined and their brain size was notably larger. > The first stone tools found in association with a hominid are found with the fossilized remains of homosexual habilis, one of the earliest homosexual species (11). This association indicates that stone tool technology now plays a role in human dietary behavior (11). At one site, dated at 2.5 mya, the fossilized bones of large mammals have been recovered with definitive evidence of fracture by stone tools for marrow acquisition (40). As yet, it is uncertain which hominid species carried out these butchering activities but this evidence shows that stone implements are now being used by at least one hominid species to process animal carcasses to obtain meat, marrow and other ASF.
2 weeks ago
Anonymous
>Meat and other ASF provide all amino acids required for human protein synthesis; animal protein is also more bioavailable than plant protein (41,42). For these reasons, a plant-eating hominoid turning to ASF would need to eat a smaller amount of ASF to satisfy all protein requirements each day than would be the case if protein requirements were being met exclusively from plant parts, even very high quality plant parts. Perhaps equally important, ASF also supply many minerals and vitamins that humans require as well as essential fatty acids >Evolving humans able to satisfy their protein and many mineral and vitamin requirements with ASF rather than plant foods, would free space in the gut for energy-rich plant foods such as fruits, nuts, starchy roots or honey. It is popularly believed that plant starches need to be cooked before they can be digested by humans, but this is not necessarily the case
2 weeks ago
Anonymous
>Using animal matter primarily to satisfy requirements for essential nutrients other than energy, and plant sources primarily for energy, is a dietary strategy compatible with hominoid gut anatomy and digestive kinetics. Such a diet, because of its high quality, would permit evolving humans to avoid the constraints imposed by body size increases in the apes (i.e., lowered dietary quality along with lowered mobility and sociality). This dietary breakthrough in the human lineage presumably was achieved through both technological and social innovations that enabled these earliest humans to greatly improve their net returns from foraging by efficiently exploiting foods from two trophic levels simultaneously, both animal and plant foods, while simultaneously greatly lowering dietary bulk >One critical aspect of this novel dietary trajectory is the fact that once ASF enter the human diet as a dependable staple, the overall nutritional quality of the plant food portion of the diet can drop drastically if necessary, so long as digestible energy is present. >This would permit intensified use by human ancestors of formerly unacceptable or marginal plant foods, including cyanogenic plant foods. Many underground storage organs are a rich source of energy but low in nutrients; some, such as manioc, contain potentially harmful chemical compounds such as cyanogenic glycosides (45). But with animal matter in the diet to supply many essential nutrients (including the sulfur-containing amino acids, essential in the detoxification of cyanogenic compounds), the low nutritional value of plant foods or some degree of potential toxicity should not pose a barrier to the human feeder, as long as digestible energy can be obtained and potentially harmful secondary compounds adequately detoxified.
2 weeks ago
Anonymous
>This change in dietary focus in early Homo, which is a clear departure from known diets of other members of the Hominoidea, both fossil and extant, was gradually reflected both in the human brain size (substantial increase) and in the form of the human gut (a shift in gut proportions and overall gut size) as well as features of the dentition (smaller teeth, jaws and muscles of mastication) (3,22). Evidence from the human fossil record, and the archaeological record, suggests a process involving increased dependence on technology and learned skills (manufacture and use of stone tools and hunting implements, techniques of food preparation) as well as social skills (cooperative hunting, division of labor, food sharing, a long period of offspring provisioning) that probably took place over a period of 2.5 million or more years >Another important aspect of ASF in the diet of human ancestors concerns the increasing importance, as human evolution progressed, of high quality, volumetrically concentrated foods for small children. E. O. Wilson has hypothesized that for more than two million years (until ~250,000 y ago), the human brain grew by a tablespoon every 100,000 y (47). The brain currently makes up 17% of a newborn human infant's weight and 75% of the weight of the four major organs combined (brain, liver, heart, kidney) (48). During the first year of life, while traditionally an infant is breastfed, the brain grows rapidly, after which its growth rate decreases
2 weeks ago
Anonymous
I don't think you understand the point of the journal article being posted. It posits that consumption of animal foods has been a key driver of human evolution, but you'll notice it is entirely adequately explained by general gut and body morphology, and has nothing to do with ocular morphology or field of view. >Eighty-seven percent of basal metabolic rate (BMR) in a 3.5 kg newborn is due to energetic demands of the brain alone. By 5 y of age, this figure has decreased to 44% and by adulthood, it is 23%. Thus, by age 5 y, human brain weight is near adult size but body weight is only one-third of adult size (48). A small child has to take in enough energy each day to fuel an almost-adult–sized brain, as well as meet high nutritional and other energetic requirements. In our evolutionary past, breast milk was the major food source for very young infants, and likely continued to be an important food for children up to the age of ≥4 y. But supplementary foods are needed after ~6 mo of age, and these must be compatible with a glucose-demanding, unusually large brain, a gut size that scales to body mass, energetic requirements that scale to the three-fourth power, a slow rate of food turnover, and a high demand for energy and nutrients by the growing and active young child
>Because of the increase in the ratio of metabolic requirements to gut capacity in homeotherms, a diet high in fibrous plant material could pose virtually insurmountable problems for small children. Meat, organs, brains, viscera and marrow are highly digestible, concentrated sources of iron, calcium, iodine, sodium and zinc as well as vitamins A, B-1, niacin, B-6, B-12, folate, vitamin K and other micronutrients, as well as high quality protein and essential fatty acids >If the dietary trajectory described above was characteristic of human ancestors, the routine, that is, daily, inclusion of ASF in the diets of children seems mandatory as most wild plant foods would not be capable of supplying the protein and micronutrients children require for optimal development and growth, nor could the gut of the child likely provide enough space, in combination with the slow food turnover rate characteristic of the human species, to secure adequate nutrition from wild plant foods alone Wild plant foods, though somewhat higher in protein and some vitamins and minerals than their cultivated counterparts, are also high in fiber and other indigestible components and most would have to be consumed in very large quantity to meet the nutritional and energetic demands of a growing and active child. >Given the postulated body and brain size of the earliest humans and the anatomy and kinetic pattern characteristics of the hominoid gut, turning increasingly to the intentional consumption of ASF on a routine rather than fortuitous basis seems the most expedient, indeed the only, dietary avenue open to the emerging human lineage. Early humans might have been able to utilize technological innovations to raise the quality of some wild plant foods through fermentation, grinding or (eventually) cooking activities. They might also have been able to secure access to physically defended, but abundant, high quality wild plant foods (using stones to open nuts, for example).
2 weeks ago
Anonymous
>Such dietary innovations require implements such as containers and grinding stones as well as the continuous availability of these unusual plant resources. For these reasons as well as those discussed above, it seems most parsimonious to view the earliest humans and their descendents as turning increasingly to animal prey to supply required amino acids and many essential micronutrients in the diet, and using plant foods primarily as an energy source. Both in quantity and composition, the fat content of wild game differs in many important respects from that of domesticated livestock and is unlikely to have posed health problems to human consumers. >Over evolutionary time, each animal species builds on the genetic template inherited from its ancestors. Given the probable diet, gut form and pattern of digestive kinetics characteristic of prehuman ancestors, it is hypothesized that the routine inclusion of animal source foods in the diet was mandatory for emergence of the human lineage. As human evolution progressed, ASF likely achieved particular importance for small children due to the energetic demands of their rapidly expanding large brain and generally high metabolic and nutritional demands relative to adults. Species discussed in this context were Pan troglodytes, Gorilla gorilla, Pongo pygmaeus and homosexual sapiens.
I think a better argument for eating meat is that one of the main theories about how the human brain became so intelligent compared to other animals is that we discovered fire and then started cooking meat and the cooking process changes the proteins in such a way that it greatly enhanced development of the brain and increased neuronal density. Basically if we didn't eat meat we'd still be in the jungle running around covered in dirt and feces
Early Humans likely had a less fattier diet than the apes they evolved from >Increasing brain size is often directly associated with a meatier diet and resultant higher caloric intake. Human entomophagy and therefore an increase in protein consumption through insects has also been proposed as a possible cause. However, it is also possible that the energy-expensive guts decreased in size in H. erectus, because the large ape gut is used to synthesize fat by fermenting plant matter which was replaced by dietary animal fat, allowing more energy to be diverted to brain growth. This would have increased brain size indirectly while maintaining the same caloric requirements of ancestor species. H. erectus may have also been the first to use a hunting and gathering food collecting strategy as a response to the increasing dependence on meat
https://en.wikipedia.org/wiki/Homo_erectus#Food
You ever seethe so much at a nonexpert btfoing your misunderstanding that you copy and pasted a whole journal article across 10 posts on IST? The above anon has. Should've just taken the L kiddo
I don't think you understand the point of the journal article being posted. It posits that consumption of animal foods has been a key driver of human evolution, but you'll notice it is entirely adequately explained by general gut and body morphology, and has nothing to do with ocular morphology or field of view. >Eighty-seven percent of basal metabolic rate (BMR) in a 3.5 kg newborn is due to energetic demands of the brain alone. By 5 y of age, this figure has decreased to 44% and by adulthood, it is 23%. Thus, by age 5 y, human brain weight is near adult size but body weight is only one-third of adult size (48). A small child has to take in enough energy each day to fuel an almost-adult–sized brain, as well as meet high nutritional and other energetic requirements. In our evolutionary past, breast milk was the major food source for very young infants, and likely continued to be an important food for children up to the age of ≥4 y. But supplementary foods are needed after ~6 mo of age, and these must be compatible with a glucose-demanding, unusually large brain, a gut size that scales to body mass, energetic requirements that scale to the three-fourth power, a slow rate of food turnover, and a high demand for energy and nutrients by the growing and active young child
The question is this:
Do humans walk upright to see far in order to hunt animals, or to reach the upper branches to eat plants?
Total vegan extinction.
those stupid plants don't have a chance against our front facing eyes
Is picrel a vicious carniore, OP?
Stop posting pictures of yourself.
Theory?
that's just a general observation that often is not true
>General
>Often not true
Hey pal. You just blow in from stupidville?
it's generally true people have 2 legs, 2 arms and 2 eyes
And deviations from this generality occur "often"?
>And deviations from this generality occur "often"?
You tell me
They all seem to have two eyes, two legs, and two arms to me.
You're such a dishonest israelite. Most monkey species are omnivores, making herbivorous apes the exception to the rule rather than the rule.
>Most monkey species are omnivores,
Insofar as they will consume insects and eggs etc, yes, correct. Very few monkeys hunt & eat meat.
The point is that their forward facing eyes are beneficial for things other than hunting prey.
>Insects and eggs aren't prey
You're really fricking dumb, dude.
Front facing eyes give brachiating frugivores the depth perception necessary to maneuverer through the branches and canopy they call home.
Despite being exclusively frugivorous or herbivorous, these monkey species haven't begun to develop side-facing eyes for greater peripheral vision to evade predation.
So even when you don't hunt or eat meat, front-facing eyes have benefits.
I don't happen to subscribe to the insane delusion that humans are ancestrally vegan or plant-based. There's no evidence for it. We need meat for optimum health. But you shouldn't argue the point with faulty logic like "front facing eyes durr".
Humans are primates, and all primates have front facing eyes, no matter what their diet is. Therefore, arguments about our "natural" or "optimum" diet ought not to make reference to our ocular morphology.
With that in mind, here is the two sentences that ACTUALLY destroyed the "humans are vegans by nature" theory.
>In humans, more than half (56%) of the total gut volume is found in the small intestine whereas all apes have by far the greatest total gut volume (>45%) in the colon. In addition, the overall size of the human gut in relation to body size is small in comparison to that of apes.
Comparative anatomy can tell you a lot about the differences between related species. Picrel. Imagine picrel had no legend - you would probably still correctly identify which of the species typically had the most animal foods in its diet.
https://www.sciencedirect.com/science/article/pii/S0022316623025518
> A brief examination of the dietary behavior of extant great apes illustrates the important role meat eating may have played in permitting members of what became the human lineage to overcome the energetic constraints imposed by increasing body size in the hominoid lineage without a concomitant increase in dietary quality.
>In plant-eating mammals, an increase in body size has far different dietary implications than an increase in body size in strongly carnivorous mammals. A pure carnivore, such as a cat, can increase in size over evolutionary time with no decrease in dietary quality. This can be seen by comparing, for example, the foods of a lynx with those of a tiger; the only difference is the size of the prey. This situation does not prevail in the case of plant-eating mammals.
>As plant-eating mammals increase in body size, invariably their dietary quality must decrease, as can be seen by comparing, for example, the foods of a tiny forest antelope with those of an elephant. Demment (33) and Demment and Van Soest (34) have postulated that changing body size is a mechanism for differentiating the feeding requirements of herbivores and note that with larger body size, the fiber content of the diet invariably rises (i.e., dietary quality decreases).
>As discussed, there is general consensus that extant hominoids, both apes and humans, come from a strongly plant-eating ancestry. Presumably selection for increased body size in gorillas and orangutans was initially associated with environmental conditions in which higher quality plant foods, for whatever reason—competition with monkeys, seasonal shortages, or other factors—simply were not available and/or accessible in sufficient quantity throughout the year. Or, conversely, it could also have been the case that lower quality plant foods were abundant and could easily and efficiently be used by a larger-bodied hominoid.
>Increasing body size over evolutionary time would permit these apes to survive on lower quality plant foods than otherwise would be possible, and to utilize plant sources that would not support smaller primates, thus getting around the postulated competition with monkeys. Large body size appears to be the single most important adaptation to diet shown by both gorillas and orangutans
>However, this increase in body size and dependence on lower quality plant foods carries with it certain negative consequences, namely, the diminution of some traits generally viewed as highly characteristic of higher primates, and in particular, a high degree of mobility and sociality. Neither gorillas nor orangutans are as active, agile and behaviorally complex as members of the genus Pan nor do they show the high degree of sociality that characterizes chimpanzees.
>In fact, orangutans are the only extant anthropoids that live solitarily, a social regression apparently dictated by their large size and the distribution patterns of their wild plant foods. Due to features of their almost exclusively plant-based diet in combination with their pattern of gut kinetics, energy input in these two great apes may often be sufficiently limited such that nonessential behaviors are not favored by selection—in other words, orangutans and gorillas may not have sufficient “extra” energy to be more active and social
>Gorillas and orangutans illustrate what can occur in the hominoid lineage on an evolutionary trajectory of increased body size and lowered dietary quality. What happens in a hominoid if, despite environmental pressures, a species is able to maintain dietary quality while continuing to feed largely on plant foods? Extant chimpanzees and bonobos illustrate this dietary strategy. They eat a high quality diet composed largely of ripe fruits, and supplement this basic fruit diet with select protein-rich young leaves, buds and flowers as well as some animal matter, largely invertebrates but occasionally smaller vertebrates
>The Pan ancestor may have been somewhat smaller than extant chimpanzees and perhaps not such an extreme ripe fruit specialist. By becoming larger in body size over evolutionary time—male chimpanzees weigh some 49 kg and females 41 kg —and increasingly specialized on ripe fruits, which are an unusually high energy food, chimpanzees and bonobos persist today as highly active and social apes. Somewhat larger body size permits chimpanzees to reap some of the metabolic benefits discussed above for the other two great apes. It also ensures access to fruit crops (chimps can displace smaller-bodied competitors from fruiting trees) and offers some degree of predator protection when traveling on the ground (chimpanzees generally travel through the forest on the ground, climbing into fruiting trees to feed)
>Because the foods on which chimpanzees specialize (ripe fruits) are high in energy, one might wonder why they retain a capacious hindgut. Why don't gut proportions of extant chimpanzees more closely approximate those of modern humans? As hominoids, chimpanzees have both a small cecum and a slow turnover rate of ingesta. They also must be able to take in sufficient plant material each day to meet or almost meet their protein and other required nutrients. Woody seeds, pectic substances, cellulose and hemicellulose are inevitable components of fruit eating. The large colon enables chimps to retain such plant materials for sufficient time to allow gut bacteria to ferment pectin and some dietary fiber (22). Volatile fatty acids produced in fermentation provide chimpanzees with energy and such energy may be essential to their survival during periods of the year when ripe fruit is in short supply.
>We now have two examples. One is that of extant hominoids (gorillas and orangutans) that represents an evolutionary trajectory associated with enlarged body size and lowered dietary quality. The other example is that of extant hominoids of somewhat smaller body size (chimpanzees), and an evolutionary trajectory predicated on “holding the line” regarding dietary quality. Early humans appear to represent an example of the only other possibility—that is, what can happen in the hominoid line when, for whatever reason, energy needs gradually begin to increase and dietary quality does not decline or remain constant but actually improves.
>Imagine a potential human ancestor weighing 35–45 kg (the size range of some Australopithecus and Paranthropus species), living in Africa during the Plio-Pleistocene. This prehuman ancestor has a gut anatomy and a pattern of digestive kinetics similar to those of extant apes. Furthermore, it has the typical hominoid diet of fruits and seeds supplemented with young leaves, flowers and other plant parts as well as occasional animal matter. A climatic change occurs such that areas of wet lowland rainforest gradually became both cooler and drier (36). As a result of this climatic shift and its effects on vegetation, higher quality plant foods become more difficult to procure (more seasonal and more diffuse in space as well as less diverse).
>Taking the path of least resistance and turning to lower quality plant foods, a dietary approach that actually was adapted by some hominid species in this environment during the Plio-Pleistocene (i.e., Paranthropus spp.) was not successful. Fossil evidence shows that by ∼1.2 mya, all such species, popularly referred to as the “robust australopithecines,” became extinct (11). If a hominoid in this environment is to persist through time as a mobile, active and social species, all data suggest it must at least hold the line on dietary quality regardless of these environmental changes. But if higher quality plant foods, particularly fruits, are becoming more scattered and seasonal, at the very least this implies higher travel costs to obtain a sufficiency. So even though our hypothetical ancestor is, for the time being, still the same size and eating the same quality diet, the energetic costs associated with the procurement of this diet are increasing.
>This hypothetical ancestor will have to eat more of its normal plant foods per unit time or become more efficient at extracting nutrients from these foods just to “stay in place” dietarily. Furthermore, conflicting demands are gradually being placed on its hominoid digestive tract. If this ancestor is to process sufficient plant material each day to satisfy its nutrient as well as energy requirements, the standard large hominoid colon would prove useful; but if it has increasing energetic demands with no decrease in dietary quality, evidence from studies of voles and birds suggest that such pressures will increase the size of the small intestine and decrease the size of the colon. This ancestral species thus appears to be approaching an evolutionary crossroads in terms of diet.
>The role played by animal source foods
>Options for diet in any mammal are limited. Food has to consist either of plant or animal matter or a mix of both, and it has to supply all nutrients (or their precursors) regarded as essential for that particular animal's needs. What spells the difference between animal species in terms of diet are the types and proportions of foods from each of these two basic dietary categories that each species can most efficiently exploit. In terms of gut anatomy and digestive kinetics, meat and other ASF, at least up to some maximum percentage of diet, pose no digestive problems for a hominoid.
> In captivity, for example, boned meat (raw beef and cooked chicken) was so well digested by common chimpanzees that it typically produced no visible residue in feces.
> Data suggest that most monkeys and all great apes can digest ASF, and that many primates appear to relish them (38, 39). But ASF are not eaten in quantity by most wild primates (39), largely because such foods are rare, generally small in size and difficult to procure, particularly in the tropical forest canopy.
>This is not to say that ASF are not important, indeed essential, dietary components, for many primate species (39). But because only small amounts typically can be secured each day, anthropoids typically fill up on higher quality plant foods and supplement this plant-based diet with as much ASF as can be secured without undue cost or effort.
>The earliest humans (members of the genus Homo) appear to have evolved in a woodland-savanna environment in Africa where ripe fruits and other high quality plant sources showed strong seasonal fluctuation. Fossil evidence suggests there may have been three or more different species of homosexual living in Africa approximately two million years ago (11). These homosexual species differed morphologically from other hominids (e.g., Australopithecus, Paranthropus) in that their check tooth size was smaller and somewhat more refined and their brain size was notably larger.
> The first stone tools found in association with a hominid are found with the fossilized remains of homosexual habilis, one of the earliest homosexual species (11). This association indicates that stone tool technology now plays a role in human dietary behavior (11). At one site, dated at 2.5 mya, the fossilized bones of large mammals have been recovered with definitive evidence of fracture by stone tools for marrow acquisition (40). As yet, it is uncertain which hominid species carried out these butchering activities but this evidence shows that stone implements are now being used by at least one hominid species to process animal carcasses to obtain meat, marrow and other ASF.
>Meat and other ASF provide all amino acids required for human protein synthesis; animal protein is also more bioavailable than plant protein (41,42). For these reasons, a plant-eating hominoid turning to ASF would need to eat a smaller amount of ASF to satisfy all protein requirements each day than would be the case if protein requirements were being met exclusively from plant parts, even very high quality plant parts. Perhaps equally important, ASF also supply many minerals and vitamins that humans require as well as essential fatty acids
>Evolving humans able to satisfy their protein and many mineral and vitamin requirements with ASF rather than plant foods, would free space in the gut for energy-rich plant foods such as fruits, nuts, starchy roots or honey. It is popularly believed that plant starches need to be cooked before they can be digested by humans, but this is not necessarily the case
>Using animal matter primarily to satisfy requirements for essential nutrients other than energy, and plant sources primarily for energy, is a dietary strategy compatible with hominoid gut anatomy and digestive kinetics. Such a diet, because of its high quality, would permit evolving humans to avoid the constraints imposed by body size increases in the apes (i.e., lowered dietary quality along with lowered mobility and sociality). This dietary breakthrough in the human lineage presumably was achieved through both technological and social innovations that enabled these earliest humans to greatly improve their net returns from foraging by efficiently exploiting foods from two trophic levels simultaneously, both animal and plant foods, while simultaneously greatly lowering dietary bulk
>One critical aspect of this novel dietary trajectory is the fact that once ASF enter the human diet as a dependable staple, the overall nutritional quality of the plant food portion of the diet can drop drastically if necessary, so long as digestible energy is present.
>This would permit intensified use by human ancestors of formerly unacceptable or marginal plant foods, including cyanogenic plant foods. Many underground storage organs are a rich source of energy but low in nutrients; some, such as manioc, contain potentially harmful chemical compounds such as cyanogenic glycosides (45). But with animal matter in the diet to supply many essential nutrients (including the sulfur-containing amino acids, essential in the detoxification of cyanogenic compounds), the low nutritional value of plant foods or some degree of potential toxicity should not pose a barrier to the human feeder, as long as digestible energy can be obtained and potentially harmful secondary compounds adequately detoxified.
>This change in dietary focus in early Homo, which is a clear departure from known diets of other members of the Hominoidea, both fossil and extant, was gradually reflected both in the human brain size (substantial increase) and in the form of the human gut (a shift in gut proportions and overall gut size) as well as features of the dentition (smaller teeth, jaws and muscles of mastication) (3,22). Evidence from the human fossil record, and the archaeological record, suggests a process involving increased dependence on technology and learned skills (manufacture and use of stone tools and hunting implements, techniques of food preparation) as well as social skills (cooperative hunting, division of labor, food sharing, a long period of offspring provisioning) that probably took place over a period of 2.5 million or more years
>Another important aspect of ASF in the diet of human ancestors concerns the increasing importance, as human evolution progressed, of high quality, volumetrically concentrated foods for small children. E. O. Wilson has hypothesized that for more than two million years (until ~250,000 y ago), the human brain grew by a tablespoon every 100,000 y (47). The brain currently makes up 17% of a newborn human infant's weight and 75% of the weight of the four major organs combined (brain, liver, heart, kidney) (48). During the first year of life, while traditionally an infant is breastfed, the brain grows rapidly, after which its growth rate decreases
>Because of the increase in the ratio of metabolic requirements to gut capacity in homeotherms, a diet high in fibrous plant material could pose virtually insurmountable problems for small children. Meat, organs, brains, viscera and marrow are highly digestible, concentrated sources of iron, calcium, iodine, sodium and zinc as well as vitamins A, B-1, niacin, B-6, B-12, folate, vitamin K and other micronutrients, as well as high quality protein and essential fatty acids
>If the dietary trajectory described above was characteristic of human ancestors, the routine, that is, daily, inclusion of ASF in the diets of children seems mandatory as most wild plant foods would not be capable of supplying the protein and micronutrients children require for optimal development and growth, nor could the gut of the child likely provide enough space, in combination with the slow food turnover rate characteristic of the human species, to secure adequate nutrition from wild plant foods alone Wild plant foods, though somewhat higher in protein and some vitamins and minerals than their cultivated counterparts, are also high in fiber and other indigestible components and most would have to be consumed in very large quantity to meet the nutritional and energetic demands of a growing and active child.
>Given the postulated body and brain size of the earliest humans and the anatomy and kinetic pattern characteristics of the hominoid gut, turning increasingly to the intentional consumption of ASF on a routine rather than fortuitous basis seems the most expedient, indeed the only, dietary avenue open to the emerging human lineage. Early humans might have been able to utilize technological innovations to raise the quality of some wild plant foods through fermentation, grinding or (eventually) cooking activities. They might also have been able to secure access to physically defended, but abundant, high quality wild plant foods (using stones to open nuts, for example).
>Such dietary innovations require implements such as containers and grinding stones as well as the continuous availability of these unusual plant resources. For these reasons as well as those discussed above, it seems most parsimonious to view the earliest humans and their descendents as turning increasingly to animal prey to supply required amino acids and many essential micronutrients in the diet, and using plant foods primarily as an energy source. Both in quantity and composition, the fat content of wild game differs in many important respects from that of domesticated livestock and is unlikely to have posed health problems to human consumers.
>Over evolutionary time, each animal species builds on the genetic template inherited from its ancestors. Given the probable diet, gut form and pattern of digestive kinetics characteristic of prehuman ancestors, it is hypothesized that the routine inclusion of animal source foods in the diet was mandatory for emergence of the human lineage. As human evolution progressed, ASF likely achieved particular importance for small children due to the energetic demands of their rapidly expanding large brain and generally high metabolic and nutritional demands relative to adults. Species discussed in this context were Pan troglodytes, Gorilla gorilla, Pongo pygmaeus and homosexual sapiens.
I think a better argument for eating meat is that one of the main theories about how the human brain became so intelligent compared to other animals is that we discovered fire and then started cooking meat and the cooking process changes the proteins in such a way that it greatly enhanced development of the brain and increased neuronal density. Basically if we didn't eat meat we'd still be in the jungle running around covered in dirt and feces
Nah, it's all about the fat, the more fat the brain can access the easier it can develop.
We are really really fatty aninals
Early Humans likely had a less fattier diet than the apes they evolved from
>Increasing brain size is often directly associated with a meatier diet and resultant higher caloric intake. Human entomophagy and therefore an increase in protein consumption through insects has also been proposed as a possible cause. However, it is also possible that the energy-expensive guts decreased in size in H. erectus, because the large ape gut is used to synthesize fat by fermenting plant matter which was replaced by dietary animal fat, allowing more energy to be diverted to brain growth. This would have increased brain size indirectly while maintaining the same caloric requirements of ancestor species. H. erectus may have also been the first to use a hunting and gathering food collecting strategy as a response to the increasing dependence on meat
https://en.wikipedia.org/wiki/Homo_erectus#Food
You are mentaly ill. Eating too much meat makes you schizophrenic, because we aren't built to deal with the iron in it.
eating only plants demonstrably causes mental illness
No it doesn't, unless they are "fortified" with iron.
Yet avoiding plants didn't help you avoid mental illness.
To be fair, many vegans have fetal alcohol syndrome and hence their eyes are facing more to the sides than to the front.
CRT thread?
If humans were meant to be vegans, why does a vegan diet make people violently sick and depressed?
You ever seethe so much at a nonexpert btfoing your misunderstanding that you copy and pasted a whole journal article across 10 posts on IST? The above anon has. Should've just taken the L kiddo
I don't think you understand the point of the journal article being posted. It posits that consumption of animal foods has been a key driver of human evolution, but you'll notice it is entirely adequately explained by general gut and body morphology, and has nothing to do with ocular morphology or field of view.
>Eighty-seven percent of basal metabolic rate (BMR) in a 3.5 kg newborn is due to energetic demands of the brain alone. By 5 y of age, this figure has decreased to 44% and by adulthood, it is 23%. Thus, by age 5 y, human brain weight is near adult size but body weight is only one-third of adult size (48). A small child has to take in enough energy each day to fuel an almost-adult–sized brain, as well as meet high nutritional and other energetic requirements. In our evolutionary past, breast milk was the major food source for very young infants, and likely continued to be an important food for children up to the age of ≥4 y. But supplementary foods are needed after ~6 mo of age, and these must be compatible with a glucose-demanding, unusually large brain, a gut size that scales to body mass, energetic requirements that scale to the three-fourth power, a slow rate of food turnover, and a high demand for energy and nutrients by the growing and active young child
in what world was that even a theory? i don't ever recall anyone in the scientific community doubting that we are omnivores like all primates
The question is this:
Do humans walk upright to see far in order to hunt animals, or to reach the upper branches to eat plants?
Total vegan extinction.