hiflier Posted February 17, 2023 Share Posted February 17, 2023 One reason could be that it allows a predator to have a greater vertical field of view in bright light when the pupil closes down. Link to comment Share on other sites More sharing options...
Huntster Posted February 18, 2023 Share Posted February 18, 2023 21 hours ago, norseman said: Ok, I am gonna try a new line of reasoning here. Europeans have roughly 2-3 percent of Neanderthal DNA. Asians have that plus 2-3 percent Denisovan DNA. This DNA gives us things like ginger hair, autism, occipital buns, and in Asians tolerance to high altitudes, etc. So why are there no slit pupils exhibited in either modern population?........ According to popular acceptance, that would be because neither Neanderthals or Denisovans were smaller ambush predators. Quote .........Danny Vendramini posits that Neanderthals had to have slit pupils in order to see in the dark. But having larger eyes would help. And no primate species exhibit slit pupils….even nocturnal ones.......... The slit pupils actually protect the pupils from intense light during the daytime, opening larger during the night to allow more light in. Thus, seeing in the dark requires larger pupils. The more nocturnal the animal, the less it needs the slit pupil for daytime use. Again, Vendramini's theory is just that; a theory. His premise that Neanderthals were pure predators is likely incorrect. It is most likely that they were every bit the hunter-gatherers as sapiens and Denisovans. But the possibility that they preyed upon sapiens as cannibals is just as possible as not, and nighttime attacks are most likely just as they are today when sapiens attack each other. Link to comment Share on other sites More sharing options...
guyzonthropus Posted February 23, 2023 Share Posted February 23, 2023 On 2/17/2023 at 12:53 PM, norseman said: Usually with cross breeding the hybrid picks up beneficial traits from the cross breeding for the environment it finds itself in. This isn't really all that true...with hybrids it's much more a hit or miss kinda thing, and it can differ with every individual which traits manifest in the phenotype. Sure, dominant genes will usually ...well.....dominate the physical form, unless both parents possess recessive genes for a given trait, but there's no telling what combinations will prove beneficial or detrimental,or potentially lethal. Of course breeding between hybrids showing similar inherited traits stand a better chance of reinforcing those traits. And with humans there's also always the issue of social preference. Such as if with thal x sapes crosses , some get the big eyes and some dont, if those with the big eyes are socially deemed lesser, less desirable they might be killed(eaten?) Or at least find finding a mate unlikely, big eyes will gradually fall from the gene pool. 1 Link to comment Share on other sites More sharing options...
norseman Posted February 23, 2023 Author Share Posted February 23, 2023 1 hour ago, guyzonthropus said: This isn't really all that true...with hybrids it's much more a hit or miss kinda thing, and it can differ with every individual which traits manifest in the phenotype. Sure, dominant genes will usually ...well.....dominate the physical form, unless both parents possess recessive genes for a given trait, but there's no telling what combinations will prove beneficial or detrimental,or potentially lethal. Of course breeding between hybrids showing similar inherited traits stand a better chance of reinforcing those traits. And with humans there's also always the issue of social preference. Such as if with thal x sapes crosses , some get the big eyes and some dont, if those with the big eyes are socially deemed lesser, less desirable they might be killed(eaten?) Or at least find finding a mate unlikely, big eyes will gradually fall from the gene pool. https://www.science.org/content/article/tibetans-inherited-high-altitude-gene-ancient-human Link to comment Share on other sites More sharing options...
guyzonthropus Posted February 26, 2023 Share Posted February 26, 2023 (edited) Sure, and the article says it's the first known example of a beneficial trait being obtained through hybridization. But then goes on to speak of the common ancestor we shared. The thing it doesn't address was the probable much higher number of traits/genes shared that proved deleterious, and either didn't pass beyond the first generation, or lead to the demise of populations bearing these genes as parents each possessing the gene reproduced and it proved lethal somehow in the homozygous form. And in its lethality it left no evidence(at least yet to be found as far as I know) in that those hybridized lines failed to survive. It is interesting how they contrasted the Tibetans with the people's of Andean Peru, although how the Mayans in particular inherited a Neanderthal gene sequence that makes them vulnerable to diabetes, while that same sequence would seem to be absent from other people's along the route of which ever pathway to central america the Mayans ancestors took, somewhat mystifies me...However the case of the Mayans does go to show that traits obtained through apparent hybridization arent always a beneficial thing, and going by evidences found, it stands at a 50:50 ratio, not including lethal combinations we have no trace of. But the authors statement that humans didn't have to wait for mutative evolution when all they had to do was have sex with other hominids possessing a desired trait, strikes me as erroneous, though it might explain some aspects of human bestiality "Hey, it was worth a try! I mean who wouldn't want their own wool, cold as these Canadian winters get, right?" but it's a little more complicated and a good bit less than guaranteed to work like a sex based "Traits-R-Us" Edited February 26, 2023 by guyzonthropus Link to comment Share on other sites More sharing options...
guyzonthropus Posted February 26, 2023 Share Posted February 26, 2023 Who knows, maybe modern humans didn't hunt down and slaughter all the other hominids or outcompeted them in times of diminished food availability, but rather we vanquished them through genetic warfare, akin to the Europeans unwitting germ warfare as they explored the new continents. Perhaps within our own genetic code is contained some sequence we "shared" with the other forms of humans, which when combined to form homozygous pairs proved incompatible, deleterious, or lethal to our neighboring cousins in a manner that dramatically diminished their numbers. Couple that with modern humans proclivity to keep on "sharing" genes with other species, as the others numbers continued to drop, we became the best/only options to species that had yet to grasp such genetics. So maybe we did indeed "sex our fellow hominids into extinction" even if we were just shooting for darker hair, or just having a good time at the block party! 1 Link to comment Share on other sites More sharing options...
HV-Squatcher Posted March 13, 2023 Share Posted March 13, 2023 Neanderthals were nocturnal carnivores. Big eyes help. 1 Link to comment Share on other sites More sharing options...
norseman Posted March 14, 2023 Author Share Posted March 14, 2023 40 minutes ago, HV-Squatcher said: Neanderthals were nocturnal carnivores. Big eyes help. That photo is hog swill. Neanderthals were day time omnivores. Just like all species in the genus Homo. https://www.bbc.com/news/science-environment-12071424 https://www.science.org/content/article/you-can-thank-your-fruit-hunting-ancestors-your-color-vision Link to comment Share on other sites More sharing options...
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