Why does thumb have only 2 knuckles?

Human hand has five fingers. Except the thumb, all fingers have 3 knuckles. Our thumb has only 2 knucles. However, the thumb takes almost half the function of the hand. Without the thumb, both hands will no longer be any more flexible. But why it has only 2 knuckles if it's that important?

According to Evolutionary Theory (Natural selection) we know, humans evolved from ancient apes (just consider it was an ancient ape). Ancient apes live in the jungle, climbing traveling by four limbs. Particularly the other four fingers were mostly used, not the thumb. Later on ancient apes started walking with their backs straightened and the upper limbs were not used (they were not climbing anymore), especially after they evolved into humans. By this time, the evolved apes learnt to hold tools, therefore thumb became very beneficial and must be used. In addition, the handling arms has developed strong muscles to make the thumb operate corresponding with other 4 fingers.

As the picture below shows, apes' hands have 'useless' thumb but the other 4 thumbs are strong enough to support them with climbing. Human's thumb is much stronger because it's been developed for us to hold tools. Having only 2 knuckles is also for us to control it while holding things easily. Just think that if our thumbs have 3 knuckles just like other fingers, how will we hold tools?

#Doyouknow #Discovery #Suggestion #AnimalWorld #Biology