Και κάτι για μας, που πάντα θεωρείται ως ένας από τους παράγοντες της κυριαρχίας μας επάνω στη Γη:
Ross: Ok, Pheebs. See how I'm making these little toys move? Opposable thumbs. Without evolution, how do you explain opposable thumbs?
Phoebe: Maybe the overlords needed them to steer their spacecrafts.
Στα σοβαρά όμως
The evolution of the fully opposable thumb is usually associated with Homo habilis, a forerunner of Homo sapiens. This, however, is the suggested result of evolution from Homo erectus (around 1 mya) via a series of intermediate anthropoid stages, and is therefore a much more complicated link.
It is possible, though, that a more likely scenario may be that the specialized precision gripping hand (equipped with opposable thumb) of Homo habilis preceded walking, with the specialized adaptation of the spine, pelvis, and lower extremities preceding a more advanced hand. And, it is logical that a conservative, highly functional adaptation be followed by a series of more complex ones that complement it. With Homo habilis, an advanced grasping-capable hand was accompanied by facultative bipedalism, possibly implying, assuming a co-opted evolutionary relationship exists, that the latter resulted from the former as obligate bipedalism was yet to follow. Walking may have been a by-product of busy hands and not vice versa.
HACNS1 (also known as Human Accelerated Region 2) is a gene enhancer 'that may have contributed to the evolution of the uniquely opposable human thumb, and possibly also modifications in the ankle or foot that allow humans to walk on two legs'. Evidence to date shows that of the 110,000 gene enhancer sequences identified in the human genome, HACNS1 has undergone the most change during the human evolution since the chimpanzee-human last common ancestor.
Δεν είναι καθόλου περίεργο που τα μοναδικά είδη που ακόμα και σήμερα εκτιμάται ότι θα μπορούσαν να δημιουργήσουν δικές τους 'αυτοκρατορίες' είναι τα άλλα είδη με αντικριστούς αντίχειρες. Και αυτό γιατί, ελλείψει άλλου τρόπου χειρισμού και εκτέλεσης περίπλοκων χειρωνακτικών εργασιών (π.χ. τηλεκίνηση ), μόνο αυτά τα είδη θα μπορούσαν να προχωρήσουν πέρα από τα πολύ βασικά στάδια εξέλιξης (και μιλάμε για εργαλεία της Λίθινης εποχής, όχι τίποτα φοβερά και τρομερά σύγχρονο)
