Basic timeline for the development of primates -- with highlights selected from an intentionally anthropocentrc point of view: up to three million years ago.
The earliest primates, called the Plesiadapiformes, are said to have speciated out of the Euarchonta very soon after the dinosaur-eliminating Comet struck, about 66 million years ago (MA).
Soon after (63 MA) the Plesiadapiformes differentiated into the so-called wet-nosed and the dry-nosed primates. We will ignore the wet-nosed in what follows. The dry nosed are represented on today's earth by both the Great Apes and us humans. One distinctive feature of the dry-nosed branching? It can't metabolize vitamin C. We, and millions of years of ancestors, have had to include fruits bearing that vitamin in our diets.
We then skip forward to 30 MA. Around this time some of the dry-nosed primates made it to South America. Perhaps the area was connected with Africa here: but on one hypothesis that wouldn't have been necessary -- a huge raft of vegetation may have carried them to the new home. Either way: from these creatures come the New World monkeys.
Back in Africa, around 25 MA the great apes, Hominoidea, make their appearance. Something new about this line: color vision. With the new improved vision came an ability to spot citric fruits amidst vegetation: a useful skill since, as noted, primates of the relevant sort can't manufacture vitamin C so we have to digest it.
The gibbon branches off about 18 MA; the orangutang about 16 MA, gorilla about 9 MA.
What is left is a clad that includes the common ancestor of chimpanzees, bonobos, and little old me.
Australopithecus afarensis (famous for the fossilized bones of 'Lucy' above) lived between 3.9 and 2.9 million years ago. The species has left very human-like bipedal footprints in volcanic ash. It had split by this time from chimps and bonobos. There are a lot of different species from this time forward, both australopithecine and hominid, but there was apparently only a narrow ecological niche for them to occupy, so they arise and die off in a confusing welter in the fossil record they have left. And we, as often as not taking our vitamin C in the form of pills in a bottle, are the only survivor of the group.
Around 3 MA these A. afarensis' were the prey of the Megantereon (saber toothed tiger). So maybe the tiger had found its own solution for the source of its vitamin C?
On that depressing dietary note I will close.
A not insignificant number among us homo sapiens, notably our sailor brothers (not many sisters in this group), also contracted Scurvy. Even as late as 2002, Afghanistan had an outbreak (after the war commenced).
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