N.Wells
Posts: 1836 Joined: Oct. 2005
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Let's clarify.
Quote | Quote | [From me] You are in the position of arguing that one of your first cousins is more closely related to you than another of your first cousins. |
[From Gary].......You are describing what I expected to find. After seeing the results it was clear that they were far from looking like cousins. |
It doesn't work that way - they are both our cousins, they are equidistant from us. In the image below, the older girls are non-identical twins, and they are holding their younger sisters, who are also non-identical twins. http://www.pregnancy-bliss.co.uk/TTTS.ht....TS.html
According to you, which of the sisters are more closely related?
There is indeed an important question about the appearance of our last common ancestor with the Pan line: did it look and behave more like Pan troglodytes, more like the bonobo, more like Lucy, or was it a bit more different and we've all evolved away from it by equal amounts? However, this is not the same as "did we evolve from the bonobo or from the common chimpanzee?". The latter is likely to be a biologically meaningless question because they are our cousins and we are equally genetically separated from both of them. (You could talk about degrees of relatedness if one lineage remained unchanged through time and spun off other lineages via critical mutations that establish separate subgroups, but you have no evidence for any lineage remaining unchanged here.)
Quote | The problem for me is that the common names now used to differentiate them are "chimp" and "bonobo". If I instead say "pygmy chimps" then very few would even know what I'm talking about. | The latter is simply not true. I agree that it would be convenient to say chimps and bonobos to mean Pan troglodytes and Pan paniscus, so that if one said "chimp" it would mean "not the bonobo". However, unfortunately for you, words in common usage don't work solely according to your say-so: you can redefine a word for a specific use in your own publication, but that's the limit. I agree that there is a push in some quarters to abandon "pygmy chimp", "gracile chimp", (etc.) in favor of "bonobo" and that a good argument can be made for doing so: Wikipedia has been edited that way. However, there is clear ongoing usage by common people and by specialists of "chimpanzee" to include the bonobo, and many experts are still using one or another of the "chimp" versions. IUCN and WWF still use both names. The authoritative six-volume book "Mammals of Africa", published in 2013 lists the animal as "Pan paniscus, Gracile Chimpanzee (Bonobo, Pygmy Chimpanzee)". It says, "The original common name was 'Pygmy Chimpanzee', but the term bonobo came into regular use after Heck (1939) reported what he mistakenly thought to be an indigenous term. Some primatologists now prefer the name 'Gracile Chimpanzee' as this is the most common descriptive name for P. paniscus. Debate continues over which of the several common names is most appropriate."
Quote | As in the theory: the very first "humans" are chromosomal Adam and Eve. Therefore: if the 2A+2B fusion exists then a specimen is human. It's that simple. |
Your mess of pottage is still not a theory. However, "human" is a term in need of clarification, and using chromosomal fusion to define humans is at least a clearly stated operational definition. Unfortunately, it is unusable, given that (as far as I know, but as always correct me if I am wrong) we have no relevant data about which fossil Hominini lie on which side of that dividing line.
Wikipedia at https://en.wikipedia.org/wiki.......ominini offers: Quote | "The subtribe Hominina is the "human" branch; that is, it contains the genus Homo exclusively. Researchers proposed the taxon Hominini on the basis that the least similar species of a trichotomy should be separated from the other two. ......
A source of confusion in determining the exact age of the Pan–Homo split is evidence of a complex speciation process rather than a clean split between the two lineages. Different chromosomes appear to have split at different times, possibly over as much as a four-million-year period, indicating a long and drawn out speciation process with large-scale hybridization events between the two emerging lineages as late as 6.3 to 5.4 million years ago according to Patterson et al. (2006).
The assumption of late hybridization was in particular based on the similarity of the X chromosome in humans and chimpanzees, suggesting a divergence as late as some 4 million years ago. This conclusion was rejected as unwarranted by Wakeley (2008), who suggested alternative explanations, including selection pressure on the X chromosome in the populations ancestral to the chimpanzee–human last common ancestor (CHLCA). |
Wikipedia at https://en.wikipedia.org/wiki.......minidae says Quote | A hominine is a member of the subfamily Homininae: gorillas, chimpanzees, and humans (excludes orangutans). A hominin is a member of the subtribe Hominina of the tribe Hominini: that is, modern humans and their closest relatives after their split from chimpanzees. A human is a member of the genus Homo, of which Homo sapiens is the only extant species, and within that Homo sapiens sapiens is the only surviving subspecies. |
See also https://en.wikipedia.org/wiki.......ncestor
Quote | But still, from what I can see the differences between bonobos and chimps are similar to chimps and gorillas. | Then you can't see much. Gorillas are way more different from all chimps than bonobos are from the common chimp. Hint: gorillas are in a different genus, look quite different, have significant differences in their skeletons, behave quite differently, and are more different genetically: study http://users.rcn.com/jkimbal....ids.jpg
Quote | After seeing the results it was clear that they were far from looking like cousins. |
https://i.ytimg.com/vi....u....ult.jpg So, which one is which, or are they both in the same species?
Bonobos and the common chimpanzee look very similar. http://ngm.nationalgeographic.com/2013.......ractive They are cousins, and they are exactly equally genetically distant from us. The question of which of them is a closer model for our ancestor is a good question, but the statement that we descended from one rather than the other is a wrong concept. If you understood biology, you'd understand this, but even you should be able to grasp that your looking more like your cousin A than your cousin B does not make A more closely related to you.
Quote | If people demand change then you must give them something that is scientifically rewarding to have changed. Else they will unknowingly make an even bigger mess of things. And you don't want that right? | Science does not work that way. If a change is merited, then science makes a change, but otherwise, it doesn't.
Quote | In our cultures the most generally accepted definition of them all starts with first humans, Adam and Eve. It's not a science based definition, but it's already there. The only thing that is needed to make it also a scientific concept is to find some truth to the story. | That's not how science works either. As Chemicat said, dump the Jesus goggles.
http://files.abovetopsecret.com/images.....8c5.jpg
And here's how to model a brain usefully: http://www.npr.org/section....heimers
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